Structural Studies of the Epitaxial Layer of a...

Research ArticleStructural Studies of the Epitaxial Layer of a Substitutional SolidSolution (GaAs)12x(ZnSe)x with Nanocrystals

A S Saidov Sh N Usmonov and D V Saparov

PhysicalndashTechnical Institute Scientific Association ldquoPhysicsndashSunrdquo Uzbek Academy of Sciences Tashkent 100084 Uzbekistan

Correspondence should be addressed to D V Saparov dadauzscinet

Received 2 May 2018 Revised 19 October 2018 Accepted 29 November 2018 Published 6 January 2019

Academic Editor David Holec

Copyright copy 2019 A S Saidov et al is is an open access article distributed under the Creative Commons Attribution Licensewhich permits unrestricted use distribution and reproduction in any medium provided the original work is properly cited

In this work we explored the possibility of growing a substitutional solid solution (GaAs)1minusx(ZnSe)x with an ordered array ofnanosize crystals on GaAs (100) substrates Grown epitaxial films were investigated by the X-ray diffraction analysis method echemical composition of the grown epitaxial films was determined by a X-ray microanalyzer along the thickness of the epitaxiallayer e photoluminescence spectrum was studied and a peak is observed at λmax 465 nm corresponding to the width of theband gap of zinc selenide EZnSe 267 eV which is apparently due to the nanocrystals ZnSe disposed in the surface region of theepitaxial film of a solid solution (GaAs)1minusx(ZnSe)x Size of nanocrystals were evaluated by an atomic force microscopy

1 Introduction

e processes of self-organization during the growth ofepitaxial films play an important role

A qualitative breakthrough in the field of obtainingsemiconductor nanostructures is associated with the effect ofself-organization of semiconductor nanostructures in het-eroepitaxial semiconductor systems e spontaneous ap-pearance of periodically ordered structures on the surfaceand in epitaxial films of semiconductors covers a wide rangeof phenomena in solid state physics and in semiconductortechnology [1] e appearance of ordered arrays of quan-tum dots due to the effect of self-organization plays animportant role in the creation of devices working on thebasis of size effects

Since the lattice parameter of the GaAs compound (aGaAs 56532 A) and ZnSe (aZnSe 56676 A) has close values andthey have the same crystalline structure (zinc blende) thesecompounds are promising materials for obtaining highquality ZnSeGaAs heterostructures and substitutional solidsolution (GaAs)1-x(ZnSe)x e quality of such hetero-structures is one of the key moments for manufacturingoptoelectronic devices such as lasers and light-emitting di-odes In addition to its technological value the ZnSeGaAsheterostructure is a model system for investigating many

fundamental aspects of surface and interfaces IIndashVIIIIndashVHowever such an interface has a complex character withrespect to stoichiometry and its chemical reactivity In Ref-erence [2] ZnSe-GaAs heterovalent heterostructures werefabricated by metalorganic vapour-phase epitaxy and char-acterized structurally and electrically Authors successfullyfabricated quantum-well structures and GaAs islands buriedinto ZnSe Funato et al had investigated MOVPE growthprocedures of GaAsZnSe heterostructures the ZnSe-GaAsheterovalent quantum structures were fabricated and theiroptical properties were characterized [3] Farrell and LaViolettestudied [4] three categories of simple heterojunctions that havelinks (1) only As-Zn (2) only Se-Ga and (3) mixed As-Zn andSe-Ga bonds and more complex interface configurations aswell as various versions of interfacial stoichiometry [5] Heshowed that the energy of the interface can be expressed as asimple sum of the energies of pairs with one bond with anaverage error of less than 3 X-ray diffraction analysis showedthat sequential annealing of the relaxed layer of ZnSe grownon GaAs (001) by molecular beam epitaxy leads to migrationof Ga toward ZnSe with a significant accumulation of Asatoms near the ZnSe At the boundary region of the hetero-structure the Ga2Se3 compound is formed as a by-productwhereas the Zn atoms diffuse from the interface into the GaAssubstrate [6] In Reference [7] the possibility of growing of the

HindawiAdvances in Materials Science and EngineeringVolume 2019 Article ID 3932195 9 pageshttpsdoiorg10115520193932195

variable-gap solid solution (GaAs)1minusx(ZnSe)x by liquid-phaseepitaxy from a Pb solution-melt on GaAs (100) substrates witha diameter of 20mm in the temperature range 870ndash730degC wasdemonstrated Epitaxial layers (GaAs)1minusx(ZnSe)x had an n-typeconductivity a carrier concentration of n 76 middot 1019 cmminus3and a monocrystalline structure with a continuously varyingcomposition x from 0 to 007

In Reference [8] on the basis of calculations of pseu-dopotential flat waves it has been shown that the enthalpy offormation and length of covalent bond Zn-Se (RZn-Se) in thematerial GaAs depend on the atoms surrounding it Takinginto account that in the usual ZnSe value of covalent bondRZn-Se 242 A it was shown that in a tetrahedral lattice ofGaAs when the impure Zn atom is surrounded with 4 Seatoms ie in the cluster Zn-Se4 its value makes RZn-Se

244 A in the cluster of Zn-Se3As RZn-Se 246 A in thecluster of Zn-Se2As2 RZn-Se 249 A and in the cluster ofZn-SeAs3 RZn-Se 251 A e similar situation is observedwhen impure Se atom in GaAs is surrounded with Zn atomse more the length of the Zn-Se bond the more it issurrounded with GaAs atoms both for cationic and foranionic knot On the basis of experimental data in the paper[9] the extrapolation dependence of width of the forbiddenzone of solid solution (GaAs)1minusx(ZnSe)x (Eg GaAsZnSe) fromconcentration ZnSe (x) is shown at the room temperatureEg GaAsZnSe 143 ndash 009 x + 126 x2 (eV) (0 le x le 1) Withinchange of concentration of ZnSe from 0 to 10 (0 le x le 01)change of Eg GaAsZnSe makes no more than 025ie practically does not change It is caused by a low pos-sibility of a clustering of Zn + Se in GaAs

In this paper the appearance of spontaneous formationof ordered arrays of nanoscale crystals on the surface ofepitaxial film of a solid solution (GaAs)1minusx(ZnSe)x has beenstudied Since the process of liquid-phase epitaxy is carriedout under conditions very close to equilibrium ones thephenomenon of self-organization plays an important roleduring the liquid-phase epitaxy

2 Theory and Calculation

To elucidate the possibility of formation of a substitutionalsolid solution for GaAs and ZnSe semiconductor compoundswe start from the thermodynamic principle of crystalchemistry which consists in the fact that in any physical andchemical system with chemical components there is achemical interaction between atoms (or ions) for all theirquantitative ratios Molecular elements IIIndashV and IIndashVIwhich do not appear on traditional state diagrams in the formof compounds are considered as new chemical compoundswhich as components of the system participate in the for-mation of solid solutions Under certain thermodynamicconditions the possibility of forming a substitutional solidsolution by molecules of semiconductor compounds is de-termined by the type of crystal lattices of the constituentcomponents their charge states and geometric dimensionsTaking into account these factors and the possibility ofreplacing two three or four nearest neighboring atoms of thesolvent A respectively with two- three- or four-atommolecules of soluble compound D the conditions for the

formation of a substitutional solid solution in the followingforms were proposed in [10]

Δz 1113944SA

zs minus 1113944iD

zi 0 (1)

|Δr| 1113944SA

rs minus 1113944iD

ri

111386811138681113868111386811138681113868111386811138681113868

111386811138681113868111386811138681113868111386811138681113868le 01 middot 1113944

SA

ri (2)

where zS and zi are the valence and rS and ri are the covalentradiuses of the atoms of solvent A and the soluble D

chemical element or elements forming molecules of solventA and soluble D compounds respectively i 1 2 3 4Condition (1) provides for the electroneutrality of solublechemical elements or compounds in a solvent semiconductormaterial it is performed when the soluble elements areizovalent to the solvent semiconductor Condition (2) pro-vides for the proximity of the geometric parameters of thesolvent A and the soluble D compound which preclude theappearance of significant distortions of the crystal lattice insolid solutions e smaller Δr the smaller the energy of theelastic distortions of the crystal lattice therefore the greaterthe crystal perfection of the substitutional solid solution andthe greater the solubility ofD inA When the difference in thesum of the covalent radiuses of the atoms of the molecules isgreater than 10 the formation of a substitutional solidsolution of these components is insignificant

For diatomic molecules of semiconductor compoundsIIIndashV and IIndashVI conditions (1) and (2) have the followingforms

Δz zIII + zV 1113857minus zII + zVI 1113857 0 (3)

Δr rIII + rV 1113857minus rII + rVI 11138571113868111386811138681113868

1113868111386811138681113868le 01 middot rIII + rV 1113857


1113868111386811138681113868le 01 middot rII + rVI 1113857(4)

where zII zIII zV and zVI are the valencies and rII rIII rVand rVI are the covalent radiuses of the elements of groupsII III V and VI respectively Since for the GaAs mole-cules zGa + zAs 3 + 5 8 and rGa + rAs 243 A and forZnSe zZn + zSe 2 + 6 8 and rZn + rSe 245 A thenconditions (3) and (4) are satisfied Since the difference inthe sum of the covalent radiuses of the atoms of the GaAsand ZnSe molecules is sim04 and the difference in the latticeparameters of the GaAs and ZnSe binary compounds is lessthan 03 the mutual molecular substitution of thesecomponents does not strongly deform the crystal latticeWhen the GaAs molecules are replaced by ZnSe moleculesthe energy of elastic distortions of the crystal lattice will beminimal therefore they form a continuous substitutionalsolid solution in the form (GaAs)1minusx(ZnSe)x in the entirerange of compositions 0 le xle 1e tetrahedral bonds of sucha solid solution are shown in Figure 1 Figure 1(a) shows thetetrahedral bonds in a (GaAs)1minusx(ZnSe)x layer enriched withgallium arsenide when some of the molecules in the GaAsmatrix are replaced by the ZnSe molecule and Figure 1(b)shows a layer enriched with ZnSe when some molecules inthe ZnSe matrix are replaced by GaAs molecules

Solid solution (GaAs)1minusx(ZnSe)xwas grownon single-crystalGaAs substrates with an orientation (100) p- and n- type

2 Advances in Materials Science and Engineering

conductivity (p 5 times 1018 smminus3 n 3 times 1017 smminus3) byliquid-phase epitaxy according to the technology described in[11] e substrates had a diameter of 20mm and a thicknessof sim400 μm To grow the layers we used a vertical type quartzreactor with horizontally arranged substrates e growth ofthe epitaxial layer was realized from a small volume of a tinsolution-melt bounded by two substrates in an atmosphere ofhydrogen purified by palladium (Figure 2) which made itpossible to minimize the amount of the consumable solution-melt First a vacuum was created in the reactor to a residualpressure of 10minus2 atmosphere then purified hydrogen waspassed through the reactor for 15min and then the heatingprocess began When the temperature reached the requiredvalue the system switched to the automatic mode During50ndash60min the solution-melt was homogenized en thesubstrates on the graphite holder were brought into contactwith the solution-melt and after filling the gaps between thesubstrates with solution-melt graphite holder was raised 1 cmabove the solution level

For the preparation of a solution-melt the solubility ofGaAs and ZnSe in Sn in the temperature range 720ndash650degCwas studied by the method of weight loss of samples ofgallium arsenide and zinc selenide placed in liquid tin andheld in it until the solution saturation Figures 3 and 4 showdata on the solubility of GaAs and ZnSe in tin as a functionof temperature Data for GaAs are taken from the work ofthe authors [12] and for ZnSe from the work of Kumar [13]

e composition of the Sn-GaAs-ZnSe solution-melt at720degC was as follows Sn 100 g GaAs 254 g and ZnSe025 g

We assume that the dissolved compounds GaAs andZnSe in liquid tin at a temperature of liquid-phase epitaxy(720degC) are mainly in the form of molecules GaAs and ZnSeis assumption is based on an analysis of the solubility ofZnSe andGaAs in Sne decomposition of ZnSemoleculeswhen dissolved in Sn into individual Zn and Se atomsaccording to the state diagram of the alloys is equivalent tothe simultaneous dissolution of Zn and Se in Sn As is

known all these three substances Zn Se and Sn at atemperature of 720degC are in a molten state (as their meltingpoints are below 720degC) and have unlimited solubilityamong themselves

Consequently if the ZnSe molecules decompose intoindividual Zn and Se atoms when ZnSe is dissolved in Sn thesolubility of ZnSe in Sn should be unlimited at 720degC It isknown that the solubility of ZnSe in Sn is very limited and isonly 03mole at 720degC [13] which indicates that the dis-solved ZnSe in the tin solution-melt is mainly in the form ofZnSe molecules

In addition one of the main conditions of liquid-phaseepitaxy is that the solution-melt must be supersaturated Ifthe ZnSe molecules in Sn decompose into individual Zn andSe atoms then at a content of 03mole ZnSe in Sn at720degC the solution-melt according to the state diagram ofthe alloys will not be supersaturated with zinc and seleniumand the epitaxial growth of ZnSe does not occur e fact

Ga

Zn

Zn

Ga

Ga

Ga

Ga

Ga

Se

Se

As

As

As

As

As

As

Se

SeZn

Zn

(a)

GaSe

As

As

Se

Se

Se

Se

Se

Ga

Ga

Ga

As

As

Zn

Zn

Zn

Zn

Zn

Zn

(b)

Figure 1 Tetrahedral bonds of the substitutional solid solution (GaAs)1minusx(ZnSe)x in layers enriched with gallium arsenide (a) and zincselenide (b)

Cassette

Zn - Se

Zn - Se

Zn - Se

Zn - Se

Zn - Se

Ga - As

Ga - As

Ga - As Ga - As

Ga - AsZn - Se

Ga - As

Solution-melt Substrate

Substrate

δ

Figure 2 Diagram of a graphite cassette with horizontally placedsubstrates and a solution-melt (the thickness of the gap between thesubstrates is δ 1mm)

Advances in Materials Science and Engineering 3

that under these conditions the epitaxial growth of ZnSe isobserved indicates that the tin solution-melt is saturatedwith ZnSe molecules and that the ZnSe molecules do notdecompose into individual Zn and Se atoms

e same conclusions can be drawn for GaAs dissolvedin Sn

erefore we assume that GaAs and ZnSe in tinsolution-melt are mainly in the form of GaAs and ZnSemolecules (Figure 2)

Since the sum of the covalent radii of the atoms of theGaAs molecules (rGa + rAs 243 A) and ZnSe (rZn + rSe 245 A) is close and the sum of the valencies of their atoms isequal (zGa + zAs zZn + zSe) then the substitution of di-atomic molecules at the crystal lattice sites of the solidsolution is energetically more favorable than the atomicsubstitution of the crystal lattice site by Ga As Zn or Seatoms separately

Based on the principle of similarity that is similar dis-solves in like it can be assumed that at the initial moment ofgrowth of the epitaxial layer crystallization of gallium arse-nide layers occurs since at a chosen epitaxy temperature thesolution is saturated by GaAs At lower temperatures con-ditions are created for the growth of the (GaAs)1minusx(ZnSe)x

solid solution since at these temperatures the solution-melton the crystallization front becomes supersaturated by gal-lium arsenide and zinc selenide Samples were grown atvarious values of liquid-phase epitaxy parameters e dis-tance between the upper and lower substrates (δ) and thebeginning and the end of the crystallization temperature (T)and the rate of forced cooling of the tin solution-melt (υ) werevaried

e epitaxial layers studied in this work were obtained ata distance between the upper and lower substrates δ 1mmthe temperature of the beginning of crystallization T

700degC the crystallization termination temperature T

650degC and the cooling rate υ 1degCmine thickness of thegrown films was 4 micron e grown films had a hole typeof conductivity Some electrophysical parameters were de-termined by the Hall method

At room temperature the resistivity of epitaxial layerswas ρ 018 Ohmmiddotcm the Hall mobility was micro 60 cm2(Vmiddots) and the concentration of the main carriers wasp 2 times 1018 cmminus3

e density of dislocations at the interface isN 107 cmminus2and on the surface of the epitaxial film is N 4 times 105 cmminus2To determine the density of dislocations the surface of the

0 2 4 6 8 10 12 14 16 18

600

650

700

750

800

850

900

GaAs (mol )

Tem

pera

ture

(degC)

Figure 3 Dependence of the solubility of GaAs in Sn on temperature

ZnSe

(mol

)

600 650 700 750 800 85001

02

03

04

05

06

07

Temperature (degC)

Figure 4 Dependence of the solubility of ZnSe in Sn on temperature [9]


epitaxial film was etched with a selective etchant HNO3 H2O(1 1) for 2ndash4 minutes then the dislocations were examinedwith a microscope MIM-4 e width of the band gap on thesurface of the epitaxial film where the composition of thesolid solution (GaAs)096(ZnSe)004 is Eg 146 eV

3 Structural Studies of a Solid Solution(GaAs)12x(ZnSe)x (0 le x le 080)

Structural studies of a GaAs substrate and an epitaxial film(GaAs)1minusx(ZnSe)x were performed at 300K on the X-raydiffractometer DRON-3M (CuKα radiation λ 015418 nm)on scheme θndash2θ in the step scanning mode

Figure 5 shows the X-ray diffraction pattern of a single-crystal GaAs substrate It can be seen that in the diffractionpattern there are several structural reflexes of selective naturewith a very large and hardly noticeable intensity at thenonmonotonic background level e analysis showed thatthe substrate surface corresponds to the crystallographic plane(100)is is evidenced by the presence on the roentgenogramof a series of selective reflexes H00 (where H 1 2 3 )intense lines (200)GaAs with dn 02822 and (400)GaAs withdn 01412 nm eir β components are visible at scatteringangles 2θ 285deg and 2θ 584deg respectively e narrowwidth (FWHM 00019 rad) the maximum intensity (4 middot105impsecminus1) and the good splitting of the (400)GaAs reflex by α1and α2 radiation with the ratio of the intensities of thecomponents close to the calculated ones I(α1) 2 middot I(α2)(Figure 5 inset) indicate the perfection of the crystal lattice ofthe substrate e background level has a nonmonotoniccharacter the steps are clearly distinguished (in the figurethey are shown by arrows) at the background level on bothsides of the structural reflex (200)GaAs and near the [200]direction at 2θ 336deg there is a wide diffuse reflection(FWHM 02 rad) e analysis showed that diffuse scat-tering is due to disordered structural fragments with acharacteristic size Ld asymp 78 A e features of the arrangementof the steps in the X-ray diffraction pattern almost equal tothe distance from the selective reflex (200)GaAs to each ofthem suggest that the steps are satellites of the structural line(200)GaAs e satellites indicate a periodic arrangement ofstructural fragments that cause diffuse scattering at 2θ 336degaround the direction (200) that is the substrate structure ismodulated Since the lattice of the substrate is cubic (asphalerite-type lattice) the modulation period can be de-termined from the angular distance Δθ (in radians) betweenthe satellite and the main reflection maximum (HKL) on theX-ray diffraction diagram using the formula S a middotH middot tgθ[(H2 + K2 + L2) middotΔθ] where θ is the scattering angle and a isthe lattice constant of the substrate [14] For a given substrateS asymp 163 A that is S asymp 2 middot Ld

Figure 6 shows X-ray diffraction of the epitaxial film ofthe solid solution (GaAs)1minusx(ZnSe)x (0 le x le 080) e X-raydiffraction pattern of the grown epitaxial filmwas significantlydifferent from the X-ray diffraction pattern of the substrateWhile maintaining nonmonotonicity background its level inthe film as compared with the background level of thesubstrate in small scattering angles fell to 5 and in mediumand high angles increased by 70 and 80 respectively Also

the intensity of the main reflections (200)GaAs and (400)GaAsincreased by 5 and 20 respectively and the ratio of theintensity with respect to the α1 and α2 radiation of the reflex(400)GaAs changed and became I(α1) ne 2 I(α2) (Figure 6insert) the steps were smoothed from the side of smallscattering angles (Figure 6) All this indicates that the surfaceof the substrate is covered with a film of appreciable thicknesse absence of other structural reflections in the roentgen-ogram shows the coincidence of the orientation of the filmwith the orientation of the substrate that is (100) e in-crease in the intensity of the main reflections (200)GaAs and(400)GaAs and the level of the inelastic background be-ginning with the mean scattering angles can be explainedby the difference in the electronic structure and elementalcomposition of the film and substrate As is known X-raysare scattered by the electrons of the ions of the material[14] Apart from the number of electrons in the filled innershells in the GaAs system the number of generalized va-lence electrons in the p-state is 4 units (4p1 and 4p3 states ofGa and As respectively) In the case of ZnSe the number ofgeneralized electrons as a result of sp hybridization ofexternal orbital reaches up to 6 units If some molecules inthe GaAs matrix are replaced by the ZnSe molecule or thegrown film has the composition (GaAs)1minusx(ZnSe)x thenthis leads to an increase in the intensity of the main reflexesof the H00 type e change in the level of the inelasticbackground at the middle and far scattering angles is alsothe result of the introduction of ZnSe molecules into theGaAs matrix since in the roentgenogram the minimumlevel of the inelastic background is reached under thecondition Zspl gt Zanod [15] In our case CuKα-radiation of acopper anode is used In the composition of the film thereis an element Zn which in the periodic system is next tocopper is leads to a noticeable increase in the inelasticX-ray scattering cross section for the electrons of thematerialrsquos ions which results in an increase in the back-ground level in the X-ray diffraction pattern In additionthere is a significant difference in the parameters of the filmand substrate lattice e parameters of the crystal lattice ofthe film and substrate perpendicular to the plane of thelayer were determined from the (200)GaAs and (400)GaAsstructural lines using the Nelson-Riley 12((cos2 θ)(sin θ)+ (cos2 θ)θ) extrapolated to θ 90deg [16] e lattice pa-rameters of the film (af ) and the substrate (as) were af 56544 and as 56465 A respectively e mismatch of thelattice constants ξ 2|as minus af |(as + af ) 00014 e ac-curacy of determining the interplanar distances and latticeparameters was sim00001 A us the grown epitaxial film isa single crystal of the substitutional solid solution in theform (GaAs)1minusx(ZnSe)x

31X-rayMicroprobeAnalysis of theChemicalCompositionofthe Solid Solution (GaAs)1minusx(ZnSe)x (0 le x le 080)Studies of the chemical composition of the grown epitaxiallayers (GaAs)1minusx(ZnSe)x were carried out on the X-raymicroanalyzer ldquoJeolrdquo JSM 5910 LV-Japan Based on theresults of the X-ray microprobe analysis the distributionprofile of Ga As Zn and Se atoms was determined as a


function of the depth of the epitaxial layer (Figure 7)Figure 7 shows that with the growth of the solid solution(GaAs)1minusx(ZnSe)x the molar ZnSe content in the epitaxiallayer first increases rapidly reaching a maximum value of x 080 which is probably due to the high supersaturation of thesolution-melt on the crystallization front by zinc selenideFurther the molar content of ZnSe slowly decreases reachingthe value x 004 on the near-surface region of the film

Since the growth of the epitaxial layer is carried out from alimited volume of the solution-melt and since the solubility ofZnSe is 10 times lower than the solubility of GaAs in tin thenafter the intensive introduction of zinc selenide into the solid

phase the solution-melt is depleted with ZnSe which furthercauses a gradual decrease in the molar content of ZnSe in thedirection of growth At a depth of 2μm from the surface of thefilm themolar content of ZnSe does not exceed 10us thegrown film is a substitutional solid solution (GaAs)1minusx(ZnSe)x(0 le x le 080) with a gradually varying composition A wide-band layer enriched with ZnSe is formed between the sub-strate and the near-surface region of the film

32 Investigation of the Surface of Epitaxial Films(GaAs)1minusx(ZnSe)x (0 le x le 004) e surface of the epitaxial

2θ (deg)

2θ (deg)

I (au

)

I (au

)

20 40 60 80

times100

times10

Sample 3film

655 660 665

108060402

0

Sample 3film

400 GaAs

1

08

06

04

02

0

124As

200Ga20

0 β

400 β

200GaAs

400GaAs

Figure 6 X-ray diffraction pattern of epitaxial film of solid solution (GaAs)1minusx(ZnSe)x (0 le x le 080)

20 40 602θ (deg)

2θ (deg)

80

655 660 665

Sample 3substrate

108060402

0

400 GaAsSample 3substrate

times10

times100

200 Ga 124 As400 β20

0 β

400 GaAs

200 GaAs

10

08

06

04

02

I (au

)

I (au

)

0

Figure 5 e X-ray diffraction pattern of the GaAs substrate


film was investigated by using an atomic force microscopeFigures 8 and 9 show two-dimensional and three-dimensional images of the surface of epitaxial films re-spectively From Figures 8 and 9 it can be seen that on asmooth surface of an epitaxial film a series of ldquohillocksrdquo witha base diameter up to sim300 nm and a height up to sim18 nm areformed

Figure 10 represents the linear dimensions of theldquohillocksrdquo corresponding to the indicated points 1 2 and 3in Figure 8 and in Figure 11 the linear dimensions corre-spond to points 4 5 and 6 in Figure 8 Analysis shows thatthe roughness of the smooth part of the surface does notexceed sim1 nm In the diffractogram of the epitaxial filmintensive narrow structural reflections (200) and (400) werepresent the absence of other structural reflexes and diffusereflection indicate that the images of the ldquohillocksrdquo presenton the AFM seem to be nanocrystals with orientation (100)and they are arranged coherently with the matrix of thecrystal lattice of the solid solution

33 Photoluminescence of the Epitaxial Layer of the SolidSolution (GaAs)1minusx(ZnSe)x (0 le x le 080) In Figure 12 thephotoluminescence spectrum (PL) of the surface of theepitaxial layer (GaAs)1minusx(ZnSe)x is given PL excitation wascarried out by laser radiation (λlaser 325 nm) from the sideof the epitaxial layer at the temperature of liquid helium(5K) the signal was recorded at the SDL-2 facility As can beseen from Figure 12 the PL spectrum of the solid solutionhas a broadband covering almost the whole visible radiationspectrum range from 400 to 760 nm with a narrow emissionpeak at λmax 465 nm corresponding to the width of theforbidden band of zinc selenide EZnSe 267 eV

Since the supplied laser radiation with energy of 382 eVis almost completely absorbed in the near-surface region ofthe epitaxial layer with a thickness of sim1 μm the luminescentradiation comes from the film sublayer where the molarZnSe content is sim4-5mol

e appearance of a narrow peak in the PL spectrum at465 nm corresponding to the width of the band gap of zincselenide EZnSe 267 eV although the molar content of ZnSein the layer from which the luminescence occurs is onlysim45mol apparently indicates that the ldquotuberclesrdquo inFigure 9 are nanocrystals consisting of ZnSe

e appearance of ZnSe nanocrystals in the matrix of thesolid solution (GaAs)1minusx(ZnSe)x is the result of the process ofself-organization during the epitaxial growth of the filmfrom the liquid-phase of a limited volume of the tin solution-melt (GaAs-ZnSe-Sn)

At the liquid-phase growing solid solutions of(GaAs)1minusx(ZnSe)x with ZnSe nanocrystals due to the latticeparameter of the GaAs and ZnSe compounds differ by only01 the obtained epitaxial film is almost perfect withoutmicrostresses in the crystal lattice

4 Conclusions

us in this paper the possibility of forming an orderedarray of nanoscale crystals in the near-surface region ofthe epitaxial film of the substitutional solid solution(GaAs)1minusx(ZnSe)x during growing from the liquid phase

1

2

3

456

40

05

00

10

15

20

05 10 15 20 25μm

11 1F height crop

μm nm

30 35 40 45

15

25

30

35

45

5

10

0

2000

Figure 8 Two-dimensional image of the surface of an epitaxial filmof a solid solution (GaAs)1minusx(ZnSe)x obtained by using an atomicforce microscope

ndash1 0 1 2 3 4

0

10

20

30

40

50

60

AsGa

ZnSe

At

(A

s G

a Zn

Se)

ickness (μm)

Figure 7 e distribution profiles of Ga As Zn and Se atoms inthe epitaxial layer of the solid solution (GaAs)1minusx(ZnSe)x

40

0

10

20nm

μm010

20

30

0 05 10 15 20 25 30 35 40 45 μm

Figure 9 ree-dimensional image of the surface of an epitaxialfilm of a solid solution (GaAs)1minusx(ZnSe)x obtained by using anatomic force microscope


due to self-organization processes is shown Studying ofregularities of formation of the ordered multitude ofnanoscale crystals in volume or on the surface of the otherbasic material gives the opportunity of operation of thesizes of nanocrystals to manufacture the devices working

on the basis of size effect and to broaden the range ofspectral sensitivity of basic material ZnSe nanocrystalsin the matrix of GaAs form the localized levels in theband gap of the solid solution (GaAs)1minusx(ZnSe)x at Ei 267 eV that lead to expansion of that spectral range of

12 1F height crop profile

8

10

6

4

2

0

0 100 200 300 400 500nm

nm

600 700 800 900

A

DX = 159 nmDY = 002 nm

DXDY = 789317DYDX = 000

A Angle = 001deg

DX = 138 nmDY = 0069 nm

DXDY = 201388DYDX = 000

B Angle = 003deg

DX = 116 nmDY = 0022 nm

DXDY = 538981DYDX = 000

C Angle = 001deg

BC

Figure 11 e linear dimensions of the ldquohillocksrdquo corresponding to the indicated points 4 5 and 6 in Figure 8

16


14

12

10

8

6

4

2

0

0 02 04 06 08μm

nm

10 12 14

DX = 287 nmDY = ndash001 nmAngle = 000degDXDY = ndash2737346DYDX = 000

DX = 254 nmDY = ndash006 nmAngle = ndash001degDXDY = ndash460314DYDX = 000

DX = 264 nmDY = ndash004 nmAngle = ndash101degDXDY = ndash682659DYDY = 000

C

C

B

B

A

A



photosensitivity of devices to high photon energy ontheir basis as it is usually observed in structures withquantum dots

Data Availability

e data used to support the findings of this study are in-cluded within the article

Conflicts of Interest

e authors declare that they have no conflicts of interest

Acknowledgments

e work was performed under the grant PFI FA-F2-003from the Academy of Sciences of the Republic of Uzbekistanis work is devoted to the sixtieth anniversary laboratory ofthe ldquoGrowth of Semiconductor Crystalsrdquo of the Physical-Technical Institute SPA ldquoPhysics-Sunrdquo

References

[1] N N Ledentsov V M Ustinov V A Shchukin P S KoprsquoevZ I Alferov and D Bimberg ldquoQuantum dot heterostructuresfabrication properties lasers (Review)rdquo Semiconductorsvol 32 no 4 pp 343ndash365 1998

[2] M Funato S Fujita and S Fujita ldquoMOVPE growth andcharacterization of ZnSe-GaAs heterovalent hetero-structuresrdquo Bulletin of Materials Science vol 18 no 4pp 343ndash359 1995

[3] M Funato ldquoTitle control of interface properties in ZnSe-GaAsheterovalent heterostructures grown by metalorganic vaporphase epitaxyrdquo Dissertation Kyoto University Kyoto Japan2000

[4] H H Farrell and R A LaViolette ldquoCation variations atsemiconductor interfaces ZnSe(001)GaAs(001) super-latticesrdquo Journal of Vacuum Science and Technology B Mi-croelectronics and Nanometer Structures vol 22 no 4pp 2250ndash2256 2004

[5] H H Farrell and R A LaViolette ldquoAnion variations atsemiconductor interfaces ZnSe(100)GaAs(100) super-latticesrdquo Journal of Vacuum Science and Technology B

Microelectronics and Nanometer Structures vol 23 no 2pp 406ndash416 2005

[6] D H Mosca W H Schreiner E M Kakuno et al ldquoChemicaland structural aspects of annealed ZnSeGaAs(001) hetero-structuresrdquo Journal of Applied Physics vol 92 no 7pp 3569ndash3572 2002

[7] A S Saidov A S Razzakov and K G Gaimnazarov ldquoLiquidphase epitaxy of (GaAs)1minusx(ZnSe)x solid solution layers from alead-based solution meltrdquo Technical Physics Letters vol 27no 11 pp 973-974 2001

[8] L G Wang and A Zunger ldquoDilute Nonisovalent (II-VI)-(III-V) semiconductor alloys monodoping codoping and clusterdoping in ZnSe-GaAsrdquo Physical Review B vol 68 no 122003

[9] M Glicksman and W D Kraeft ldquoEffect of high intrinsic ionconcentrations on electron energies in solid solutions of III-Vand II-VI semiconductorsrdquo Solid-State Electronics vol 28no 1-2 pp 151ndash161 1985

[10] M S Saidov ldquoConductors crystallization-a condition forsynthesizing new dopant compoundsrdquo Applied Solar Energyvol 46 no 1 pp 80-81 2010

[11] A S Saidov A Sh Razzakov V A Risaeva andE A Koschanov ldquoLiquid-phase epitaxy of solid solutions(Ge2)1minusx(ZnSe)xrdquo Materials Chemistry and Physics vol 68no 1ndash3 pp 1ndash6 2001

[12] A S Saidov M S Saidov and E A Koshchanov Liquid-Phase Epitaxy of Compensated Gallium Arsenide LayersTashkent Publishing house ldquoFANrdquo Tirana Albania 1986

[13] V Kumar ldquoInternational workshop on the physics of semi-conductor devices (december 14ndash18 1999 Delhi) 2rdquoin Pro-ceedings of SPIE vol 3795 p 14252 Allied PublishersMumbai India December 2000

[14] A A Rusakov X-Ray Diffraction of Metals AtomizdatMoscow Russia 1977 in Russian

[15] T I Krasovitskaya Electronic Structures of Atoms and theChemical Bond Prosveshchenie Moscow Russia 1980 inRussian

[16] S S Gorelik L N Rostorguev and Yu A Skakov X-RayDiffraction and Electron Optical Analysis MetallurgiyaMoscow Russia 1970 in Russian

103

102

Inte

nsity

(au

)

101

100

300 400 500 600λ (nm)

λmax = 465 nm

700 800 900

Figure 12 e photoluminescence spectrum of epitaxial layer ofthe solid solution (GaAs)1minusx(ZnSe)x at a temperature of 5K


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BioMed Research InternationalMaterials

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Journal ofNanomaterials

Submit your manuscripts atwwwhindawicom

variable-gap solid solution (GaAs)1minusx(ZnSe)x by liquid-phaseepitaxy from a Pb solution-melt on GaAs (100) substrates witha diameter of 20mm in the temperature range 870ndash730degC wasdemonstrated Epitaxial layers (GaAs)1minusx(ZnSe)x had an n-typeconductivity a carrier concentration of n 76 middot 1019 cmminus3and a monocrystalline structure with a continuously varyingcomposition x from 0 to 007

In Reference [8] on the basis of calculations of pseu-dopotential flat waves it has been shown that the enthalpy offormation and length of covalent bond Zn-Se (RZn-Se) in thematerial GaAs depend on the atoms surrounding it Takinginto account that in the usual ZnSe value of covalent bondRZn-Se 242 A it was shown that in a tetrahedral lattice ofGaAs when the impure Zn atom is surrounded with 4 Seatoms ie in the cluster Zn-Se4 its value makes RZn-Se

244 A in the cluster of Zn-Se3As RZn-Se 246 A in thecluster of Zn-Se2As2 RZn-Se 249 A and in the cluster ofZn-SeAs3 RZn-Se 251 A e similar situation is observedwhen impure Se atom in GaAs is surrounded with Zn atomse more the length of the Zn-Se bond the more it issurrounded with GaAs atoms both for cationic and foranionic knot On the basis of experimental data in the paper[9] the extrapolation dependence of width of the forbiddenzone of solid solution (GaAs)1minusx(ZnSe)x (Eg GaAsZnSe) fromconcentration ZnSe (x) is shown at the room temperatureEg GaAsZnSe 143 ndash 009 x + 126 x2 (eV) (0 le x le 1) Withinchange of concentration of ZnSe from 0 to 10 (0 le x le 01)change of Eg GaAsZnSe makes no more than 025ie practically does not change It is caused by a low pos-sibility of a clustering of Zn + Se in GaAs

In this paper the appearance of spontaneous formationof ordered arrays of nanoscale crystals on the surface ofepitaxial film of a solid solution (GaAs)1minusx(ZnSe)x has beenstudied Since the process of liquid-phase epitaxy is carriedout under conditions very close to equilibrium ones thephenomenon of self-organization plays an important roleduring the liquid-phase epitaxy

2 Theory and Calculation

To elucidate the possibility of formation of a substitutionalsolid solution for GaAs and ZnSe semiconductor compoundswe start from the thermodynamic principle of crystalchemistry which consists in the fact that in any physical andchemical system with chemical components there is achemical interaction between atoms (or ions) for all theirquantitative ratios Molecular elements IIIndashV and IIndashVIwhich do not appear on traditional state diagrams in the formof compounds are considered as new chemical compoundswhich as components of the system participate in the for-mation of solid solutions Under certain thermodynamicconditions the possibility of forming a substitutional solidsolution by molecules of semiconductor compounds is de-termined by the type of crystal lattices of the constituentcomponents their charge states and geometric dimensionsTaking into account these factors and the possibility ofreplacing two three or four nearest neighboring atoms of thesolvent A respectively with two- three- or four-atommolecules of soluble compound D the conditions for the

formation of a substitutional solid solution in the followingforms were proposed in [10]

Δz 1113944SA

zs minus 1113944iD

zi 0 (1)

|Δr| 1113944SA

rs minus 1113944iD

ri

111386811138681113868111386811138681113868111386811138681113868

111386811138681113868111386811138681113868111386811138681113868le 01 middot 1113944

SA

ri (2)

where zS and zi are the valence and rS and ri are the covalentradiuses of the atoms of solvent A and the soluble D

chemical element or elements forming molecules of solventA and soluble D compounds respectively i 1 2 3 4Condition (1) provides for the electroneutrality of solublechemical elements or compounds in a solvent semiconductormaterial it is performed when the soluble elements areizovalent to the solvent semiconductor Condition (2) pro-vides for the proximity of the geometric parameters of thesolvent A and the soluble D compound which preclude theappearance of significant distortions of the crystal lattice insolid solutions e smaller Δr the smaller the energy of theelastic distortions of the crystal lattice therefore the greaterthe crystal perfection of the substitutional solid solution andthe greater the solubility ofD inA When the difference in thesum of the covalent radiuses of the atoms of the molecules isgreater than 10 the formation of a substitutional solidsolution of these components is insignificant

For diatomic molecules of semiconductor compoundsIIIndashV and IIndashVI conditions (1) and (2) have the followingforms

Δz zIII + zV 1113857minus zII + zVI 1113857 0 (3)


1113868111386811138681113868le 01 middot rIII + rV 1113857


1113868111386811138681113868le 01 middot rII + rVI 1113857(4)

where zII zIII zV and zVI are the valencies and rII rIII rVand rVI are the covalent radiuses of the elements of groupsII III V and VI respectively Since for the GaAs mole-cules zGa + zAs 3 + 5 8 and rGa + rAs 243 A and forZnSe zZn + zSe 2 + 6 8 and rZn + rSe 245 A thenconditions (3) and (4) are satisfied Since the difference inthe sum of the covalent radiuses of the atoms of the GaAsand ZnSe molecules is sim04 and the difference in the latticeparameters of the GaAs and ZnSe binary compounds is lessthan 03 the mutual molecular substitution of thesecomponents does not strongly deform the crystal latticeWhen the GaAs molecules are replaced by ZnSe moleculesthe energy of elastic distortions of the crystal lattice will beminimal therefore they form a continuous substitutionalsolid solution in the form (GaAs)1minusx(ZnSe)x in the entirerange of compositions 0 le xle 1e tetrahedral bonds of sucha solid solution are shown in Figure 1 Figure 1(a) shows thetetrahedral bonds in a (GaAs)1minusx(ZnSe)x layer enriched withgallium arsenide when some of the molecules in the GaAsmatrix are replaced by the ZnSe molecule and Figure 1(b)shows a layer enriched with ZnSe when some molecules inthe ZnSe matrix are replaced by GaAs molecules

Solid solution (GaAs)1minusx(ZnSe)xwas grownon single-crystalGaAs substrates with an orientation (100) p- and n- type









Ga

Zn

Zn

Ga

Ga

Ga

Ga

Ga

Se

Se

As

As

As

As

As

As

Se

SeZn

Zn

(a)

GaSe

As

As

Se

Se

Se

Se

Se

Ga

Ga

Ga

As

As

Zn

Zn

Zn

Zn

Zn

Zn

(b)


Cassette

Zn - Se

Zn - Se

Zn - Se

Zn - Se

Zn - Se

Ga - As

Ga - As

Ga - As Ga - As

Ga - AsZn - Se

Ga - As


Substrate

δ














0 2 4 6 8 10 12 14 16 18

600

650

700

750

800

850

900

GaAs (mol )

Tem

pera

ture

(degC)


ZnSe

(mol

)

600 650 700 750 800 85001

02

03

04

05

06

07

Temperature (degC)















2θ (deg)

2θ (deg)

I (au

)

I (au

)

20 40 60 80

times100

times10

Sample 3film

655 660 665

108060402

0

Sample 3film

400 GaAs

1

08

06

04

02

0

124As

200Ga20

0 β

400 β

200GaAs

400GaAs


20 40 602θ (deg)

2θ (deg)

80

655 660 665

Sample 3substrate

108060402

0


times10

times100

200 Ga 124 As400 β20

0 β

400 GaAs

200 GaAs

10

08

06

04

02

I (au

)

I (au

)

0










4 Conclusions


1

2

3

456

40

05

00

10

15

20

05 10 15 20 25μm

11 1F height crop

μm nm

30 35 40 45

15

25

30

35

45

5

10

0

2000


ndash1 0 1 2 3 4

0

10

20

30

40

50

60

AsGa

ZnSe

At

(A

s G

a Zn

Se)

ickness (μm)


40

0

10

20nm

μm010

20

30

0 05 10 15 20 25 30 35 40 45 μm






8

10

6

4

2

0

0 100 200 300 400 500nm

nm

600 700 800 900

A

DX = 159 nmDY = 002 nm

DXDY = 789317DYDX = 000

A Angle = 001deg

DX = 138 nmDY = 0069 nm

DXDY = 201388DYDX = 000

B Angle = 003deg

DX = 116 nmDY = 0022 nm

DXDY = 538981DYDX = 000

C Angle = 001deg

BC


16


14

12

10

8

6

4

2

0

0 02 04 06 08μm

nm

10 12 14




C

C

B

B

A

A




Data Availability




Acknowledgments


References


















103

102

Inte

nsity

(au

)

101

100

300 400 500 600λ (nm)

λmax = 465 nm

700 800 900





Advances in



Journal of

Chemistry















Journal of





Volume 2018









Journal of


Na

nom

ate

ria

ls











Ga

Zn

Zn

Ga

Ga

Ga

Ga

Ga

Se

Se

As

As

As

As

As

As

Se

SeZn

Zn

(a)

GaSe

As

As

Se

Se

Se

Se

Se

Ga

Ga

Ga

As

As

Zn

Zn

Zn

Zn

Zn

Zn

(b)


Cassette

Zn - Se

Zn - Se

Zn - Se

Zn - Se

Zn - Se

Ga - As

Ga - As

Ga - As Ga - As

Ga - AsZn - Se

Ga - As


Substrate

δ














0 2 4 6 8 10 12 14 16 18

600

650

700

750

800

850

900

GaAs (mol )

Tem

pera

ture

(degC)


ZnSe

(mol

)

600 650 700 750 800 85001

02

03

04

05

06

07

Temperature (degC)















2θ (deg)

2θ (deg)

I (au

)

I (au

)

20 40 60 80

times100

times10

Sample 3film

655 660 665

108060402

0

Sample 3film

400 GaAs

1

08

06

04

02

0

124As

200Ga20

0 β

400 β

200GaAs

400GaAs


20 40 602θ (deg)

2θ (deg)

80

655 660 665

Sample 3substrate

108060402

0


times10

times100

200 Ga 124 As400 β20

0 β

400 GaAs

200 GaAs

10

08

06

04

02

I (au

)

I (au

)

0










4 Conclusions


1

2

3

456

40

05

00

10

15

20

05 10 15 20 25μm

11 1F height crop

μm nm

30 35 40 45

15

25

30

35

45

5

10

0

2000


ndash1 0 1 2 3 4

0

10

20

30

40

50

60

AsGa

ZnSe

At

(A

s G

a Zn

Se)

ickness (μm)


40

0

10

20nm

μm010

20

30

0 05 10 15 20 25 30 35 40 45 μm






8

10

6

4

2

0

0 100 200 300 400 500nm

nm

600 700 800 900

A

DX = 159 nmDY = 002 nm

DXDY = 789317DYDX = 000

A Angle = 001deg

DX = 138 nmDY = 0069 nm

DXDY = 201388DYDX = 000

B Angle = 003deg

DX = 116 nmDY = 0022 nm

DXDY = 538981DYDX = 000

C Angle = 001deg

BC


16


14

12

10

8

6

4

2

0

0 02 04 06 08μm

nm

10 12 14




C

C

B

B

A

A




Data Availability




Acknowledgments


References


















103

102

Inte

nsity

(au

)

101

100

300 400 500 600λ (nm)

λmax = 465 nm

700 800 900





Advances in



Journal of

Chemistry















Journal of





Volume 2018









Journal of


Na

nom

ate

ria

ls















0 2 4 6 8 10 12 14 16 18

600

650

700

750

800

850

900

GaAs (mol )

Tem

pera

ture

(degC)


ZnSe

(mol

)

600 650 700 750 800 85001

02

03

04

05

06

07

Temperature (degC)















2θ (deg)

2θ (deg)

I (au

)

I (au

)

20 40 60 80

times100

times10

Sample 3film

655 660 665

108060402

0

Sample 3film

400 GaAs

1

08

06

04

02

0

124As

200Ga20

0 β

400 β

200GaAs

400GaAs


20 40 602θ (deg)

2θ (deg)

80

655 660 665

Sample 3substrate

108060402

0


times10

times100

200 Ga 124 As400 β20

0 β

400 GaAs

200 GaAs

10

08

06

04

02

I (au

)

I (au

)

0










4 Conclusions


1

2

3

456

40

05

00

10

15

20

05 10 15 20 25μm

11 1F height crop

μm nm

30 35 40 45

15

25

30

35

45

5

10

0

2000


ndash1 0 1 2 3 4

0

10

20

30

40

50

60

AsGa

ZnSe

At

(A

s G

a Zn

Se)

ickness (μm)


40

0

10

20nm

μm010

20

30

0 05 10 15 20 25 30 35 40 45 μm






8

10

6

4

2

0

0 100 200 300 400 500nm

nm

600 700 800 900

A

DX = 159 nmDY = 002 nm

DXDY = 789317DYDX = 000

A Angle = 001deg

DX = 138 nmDY = 0069 nm

DXDY = 201388DYDX = 000

B Angle = 003deg

DX = 116 nmDY = 0022 nm

DXDY = 538981DYDX = 000

C Angle = 001deg

BC


16


14

12

10

8

6

4

2

0

0 02 04 06 08μm

nm

10 12 14




C

C

B

B

A

A




Data Availability




Acknowledgments


References


















103

102

Inte

nsity

(au

)

101

100

300 400 500 600λ (nm)

λmax = 465 nm

700 800 900





Advances in



Journal of

Chemistry















Journal of





Volume 2018









Journal of


Na

nom

ate

ria

ls
















2θ (deg)

2θ (deg)

I (au

)

I (au

)

20 40 60 80

times100

times10

Sample 3film

655 660 665

108060402

0

Sample 3film

400 GaAs

1

08

06

04

02

0

124As

200Ga20

0 β

400 β

200GaAs

400GaAs


20 40 602θ (deg)

2θ (deg)

80

655 660 665

Sample 3substrate

108060402

0


times10

times100

200 Ga 124 As400 β20

0 β

400 GaAs

200 GaAs

10

08

06

04

02

I (au

)

I (au

)

0










4 Conclusions


1

2

3

456

40

05

00

10

15

20

05 10 15 20 25μm

11 1F height crop

μm nm

30 35 40 45

15

25

30

35

45

5

10

0

2000


ndash1 0 1 2 3 4

0

10

20

30

40

50

60

AsGa

ZnSe

At

(A

s G

a Zn

Se)

ickness (μm)


40

0

10

20nm

μm010

20

30

0 05 10 15 20 25 30 35 40 45 μm






8

10

6

4

2

0

0 100 200 300 400 500nm

nm

600 700 800 900

A

DX = 159 nmDY = 002 nm

DXDY = 789317DYDX = 000

A Angle = 001deg

DX = 138 nmDY = 0069 nm

DXDY = 201388DYDX = 000

B Angle = 003deg

DX = 116 nmDY = 0022 nm

DXDY = 538981DYDX = 000

C Angle = 001deg

BC


16


14

12

10

8

6

4

2

0

0 02 04 06 08μm

nm

10 12 14




C

C

B

B

A

A




Data Availability




Acknowledgments


References


















103

102

Inte

nsity

(au

)

101

100

300 400 500 600λ (nm)

λmax = 465 nm

700 800 900





Advances in



Journal of

Chemistry















Journal of





Volume 2018









Journal of


Na

nom

ate

ria

ls











4 Conclusions


1

2

3

456

40

05

00

10

15

20

05 10 15 20 25μm

11 1F height crop

μm nm

30 35 40 45

15

25

30

35

45

5

10

0

2000


ndash1 0 1 2 3 4

0

10

20

30

40

50

60

AsGa

ZnSe

At

(A

s G

a Zn

Se)

ickness (μm)


40

0

10

20nm

μm010

20

30

0 05 10 15 20 25 30 35 40 45 μm






8

10

6

4

2

0

0 100 200 300 400 500nm

nm

600 700 800 900

A

DX = 159 nmDY = 002 nm

DXDY = 789317DYDX = 000

A Angle = 001deg

DX = 138 nmDY = 0069 nm

DXDY = 201388DYDX = 000

B Angle = 003deg

DX = 116 nmDY = 0022 nm

DXDY = 538981DYDX = 000

C Angle = 001deg

BC


16


14

12

10

8

6

4

2

0

0 02 04 06 08μm

nm

10 12 14




C

C

B

B

A

A




Data Availability




Acknowledgments


References


















103

102

Inte

nsity

(au

)

101

100

300 400 500 600λ (nm)

λmax = 465 nm

700 800 900





Advances in



Journal of

Chemistry















Journal of





Volume 2018









Journal of


Na

nom

ate

ria

ls







8

10

6

4

2

0

0 100 200 300 400 500nm

nm

600 700 800 900

A

DX = 159 nmDY = 002 nm

DXDY = 789317DYDX = 000

A Angle = 001deg

DX = 138 nmDY = 0069 nm

DXDY = 201388DYDX = 000

B Angle = 003deg

DX = 116 nmDY = 0022 nm

DXDY = 538981DYDX = 000

C Angle = 001deg

BC


16


14

12

10

8

6

4

2

0

0 02 04 06 08μm

nm

10 12 14




C

C

B

B

A

A




Data Availability




Acknowledgments


References


















103

102

Inte

nsity

(au

)

101

100

300 400 500 600λ (nm)

λmax = 465 nm

700 800 900





Advances in



Journal of

Chemistry















Journal of





Volume 2018









Journal of


Na

nom

ate

ria

ls





Data Availability




Acknowledgments


References


















103

102

Inte

nsity

(au

)

101

100

300 400 500 600λ (nm)

λmax = 465 nm

700 800 900





Advances in



Journal of

Chemistry















Journal of





Volume 2018









Journal of


Na

nom

ate

ria

ls






Advances in



Journal of

Chemistry















Journal of





Volume 2018









Journal of


Na

nom

ate

ria

ls




Structural Studies of the Epitaxial Layer of a...

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