H. Wolf 1 , F. Wagner 1 , J. Kronenberg 1 , H. Wolf 1 , Th. Wichert 1 , K. Johnston 1

1

H. Wolf1, F. Wagner1, J. Kronenberg1, H. Wolf1, Th. Wichert1, K. Johnston1

and the ISOLDE Collaboration

1) Technische Physik, Universität des Saarlandes, D-66123 Saarbrücken, Germany

Supported by the BMBF, contract 05 KK7TS1

Diffusion behaviour of short lived isotopesin II‑VI semiconductors

2

Workshop 2006

Ag in CdTe: 828K, 60 min

0 200 400 600 800

1011

1012

1013

0 200 4001012

1013

1014

1015

0 200 400 600 800

1012

1013

1014

Cd atmosphere Te atmospherevacuum

conc

entra

tion

(cm

-3)

depth (m)

depth (m)

depth (m)

• Up hill diffusion• Not explainable by fick´s laws

0 100 200 300 400 500108

109

1010

1011

1012

1013

1014

conc

entra

tion

(cm

-3)

depth (µm)


vacuum Cd atmosphere

tAg

AgDAgJ

)(

H. Wolf, F. Wagner, Th. Wichert, Phys. Rev. Lett. 94, 125901 (2005)

3

0.5 – 0.8 mm 500 K - 1000 K

annealing111Ag

30 nm

111Ag

111Ag

radiotracer technique

CdTe

4

radiotracer technique

0 100 200 300 400 500108

109

1010

1011

1012

1013

1014

conc

entra

tion

(cm

-3)

depth (µm)

5

Workshop 2006


0 200 400 600 800

1011

1012

1013

0 200 4001012

1013

1014

1015

0 200 400 600 800

1012

1013

1014


conc

entra

tion

(cm

-3)

depth (m)

depth (m)

depth (m)

Up hill diffusionWhat can we learn?

6

Workshop 2007

• Interstitial Cd

• Donator (Cdi++)

•Cd vacancy

• Acceptor (VCd--)

• Substitutionell Ag

• Acceptor (AgCd-)

• Interstitial Ag

• Donator (Agi+)

Cd Te

7

-0,2

-0,1

0,0

0,1

0 200 400 600 800

1011

1012

1013

-4x1016

-3x1016

-2x1016

-1x1016

01x1016

2x1016

VCd

--Cdi++

depth (µm)

µ F eV

n npCd

i++

Ag+i

conc

entra

tion

(cm

-3)

[C

] (cm

-3)

0 200 400 600 800

1011

1012

1013

-4x1016

-3x1016

-2x1016

-1x1016

01x1016

2x1016

Ag+i

conc

entra

tion

(cm

-3)

depth (µm)

[C

] (cm

-3)

Cd-atmosphere (828 K 60 min)

• Cd-atmosphere: Cdi in diffusion

[ΔC] = [Cdi]-[VCd]

• [ΔC] determines µF

• [Ag] = [Agi+]

• Agi+ behaves like h+

• Ag profile reflect µF und [ΔC]

Workshop 2007

[ΔCini]

Cdi Cdi

8

Workshop 2007


0 200 400 600 800

1011

1012

1013

0 200 4001012

1013

1014

1015

0 200 400 600 800

1012

1013

1014


conc

entra

tion

(cm

-3)

depth (m)

depth (m)

depth (m)

Information about: Diffusion coefficients Formation energies Ionizations energies

9

Ag

Ia

IIa

IIIb IV b Vb V Ib V IIb V III Ib IIb

IIIa IVa Va V Ia V IIa

V III

Zn

Cd In

N

Sb

S

Se

Te

Cl

Br

I

As33

15

7

H

B e

M g

C a S c T i

S r Y

V C r M n

Z r N b M o T c

F e C o N i

R u R h P d

B

A l

G a

C

S i

G e

S n

P

O F

H e

N e

A r

K r

X e

C u

4

12

20 21 22 23 24 25 26 27 28 29 30 31

13

5

32

14

6

34

16

8

35

17

9

36

18

10

2

38 39 40 41 42 43 44 45 46 47 48 49 50 51 53 54

Li

Rb

Na

K

1

3

11

19

37

Ce Pr Nd Pm Sm Eu Gd Tb Dy Ho Er Tm Yb Lu58 59 60 61 62 63 64 65 66 67 68 69 70 71

La57

Ba La Hf Ta W Re Os Ir Pt Au Hg Tl Pb Bi56 57 72 73 74 75 76 77 78 79 80 81 82 83

Cs55

II-VI semiconductors

10

Ag in different semiconductors

0 200 400 600 800109

1010

1011

1012

1013

conc

entra

tion

(cm

-3)

depth (µm)

0 200 400108

109

1010

1011

1012

1013

1014

conc

entra

tion

(cm

-3)

depth (µm)

0 200 400 600 800

1011

1012

1013

conc

entra

tion

(cm

-3)

depth (µm)

CdTe Cd0.96Zn0.04Te ZnTe828K, 60 min 828K, 60 min 928K, 24 h

Comparable behavior of Ag in different II-VI semiconductors

Cd atmosphere Cd atmosphere Zn atmosphere

11

Ag

Ia

IIa



V III

Zn

Cd In

N

Sb

S

Se

Te

Cl

Br

I

As33

15

7

H

B e

M g

C a S c T i

S r Y

V C r M n

Z r N b M o T c

F e C o N i

R u R h P d

B

A l

G a

C

S i

G e

S n

P

O F

H e

N e

A r

K r

X e

C u

4

12

20 21 22 23 24 25 26 27 28 29 30 31

13

5

32

14

6

34

16

8

35

17

9

36

18

10

2

38 39 40 41 42 43 44 45 46 47 48 49 50 51 53 54

Li

Rb

Na

K

1

3

11

19

37


La57


Cs55

12

Comparison Ag and Cu in CdTe

0 200 400 600 8001010

1011

1012

1013

Kon

zent

ratio

n (c

m-3)

Tiefe (m)

CdTe102767Cu

0 200 400 600 800

1011

1012

1013

Kon

zent

ratio

n (c

m-3)

Tiefe (m)

Cu Ag

depth [µm]

conc

entra

tion

[cm

-3]

depth [µm]

Comparable behavior of Ag and Cu

Cd atmosphere, 828 K, 60 min

13

Ag

Ia

IIa



V III

Zn

Cd In

N

Sb

S

Se

Te

Cl

Br

I

As33

15

7

H

B e

M g

C a S c T i

S r Y

V C r M n

Z r N b M o T c

F e C o N i

R u R h P d

B

A l

G a

C

S i

G e

S n

P

O F

H e

N e

A r

K r

X e

C u

4

12

20 21 22 23 24 25 26 27 28 29 30 31

13

5

32

14

6

34

16

8

35

17

9

36

18

10

2

38 39 40 41 42 43 44 45 46 47 48 49 50 51 53 54

Li

Rb

Na

K

1

3

11

19

37


La57


Cs55

14

Au diffusion in CdZnTe

D(Au) >> D(Teramoto et al.) 1µm

No uphil diffusion?

I. Teramoto and S. Takayanagi, J. Phys. Soc. Jpn. 17 (1962) 1137.

0 200 400 600 800109

1010

1011

1012

conc

entra

tion

(cm

-3)

depth (µm)

CdZnTe: 828K, 60 min, Cd atmosphere

Pre anneal: 928K, Te atmosphere

0 200 400 600 800109

1010

1011

1012

conc

entra

tion

(cm

-3)

depth (µm)

15


0 200 400 600 800

1011

1012

1013

-4x1016

-3x1016

-2x1016

-1x1016

01x1016

2x1016

Ag+i

conc

entra

tion

(cm

-3)

depth (µm)

[C

] (cm

-3)

[ΔCini]

Cdi Cdi

16


0 200 400 600 800109

1010

1011

1012

conc

entra

tion

(cm

-3)

depth (µm)

CdZnTe: 828K, 60 min, Cd atmosphere

Up hill diffusion can be observed for Au [ΔCini] < 0 (VCd

--)

Pre anneal: 928K, Te atmosphere

0 200 400 600 800109

1010

1011

1012

conc

entra

tion

(cm

-3)

depth (µm)

17

Ag

Ia

IIa



V III

Zn

Cd In

N

Sb

S

Se

Te

Cl

Br

I

As33

15

7

H

B e

M g

C a S c T i

S r Y

V C r M n

Z r N b M o T c

F e C o N i

R u R h P d

B

A l

G a

C

S i

G e

S n

P

O F

H e

N e

A r

K r

X e

C u

4

12

20 21 22 23 24 25 26 27 28 29 30 31

13

5

32

14

6

34

16

8

35

17

9

36

18

10

2

38 39 40 41 42 43 44 45 46 47 48 49 50 51 53 54

Li

Rb

Na

K

1

3

11

19

37


La57


Cs55

18

Na diffusion in CdTe

Na diffusion show up hill diffusion

0 200 400 600 800108

109

1010

1011

10h: vacuum 1h: Cd atmosphere

conc

entra

tion

(cm

-3)

depth (µm)

Na: 750 K

19

0 200 400 600 800108

109

1010

1011

1012

1013

9h: vacuum10h: Cd atmosphere

conc

entra

tion

(cm

-3)

depth (µm)

n p

K diffusion in CdTe

Weak penetration of K diffusion in n-type part no peak-shaped profile

0 200 400 600 800

1011

1012

1013

0 200 4001012

1013

1014

1015

0 200 400 600 800

1012

1013

1014


conc

entra

tion

(cm

-3)

depth (m)

depth (m)

depth (m)

n p

K: 750K Ag: 828K

20

Ag

Ia

IIa



V III

Zn

Cd In

N

Sb

S

Se

Te

Cl

Br

I

As33

15

7

H

B e

M g

C a S c T i

S r Y

V C r M n

Z r N b M o T c

F e C o N i

R u R h P d

B

A l

G a

C

S i

G e

S n

P

O F

H e

N e

A r

K r

X e

C u

4

12

20 21 22 23 24 25 26 27 28 29 30 31

13

5

32

14

6

34

16

8

35

17

9

36

18

10

2

38 39 40 41 42 43 44 45 46 47 48 49 50 51 53 54

Li

Rb

Na

K

1

3

11

19

37


La57


Cs55

K, Mn and Fe diffuses to slow

21

Ag

Ia

IIa



V III

Zn

Cd In

N

Sb

S

Se

Te

Cl

Br

I

As33

15

7

H

B e

M g

C a S c T i

S r Y

V C r M n

Z r N b M o T c

F e C o N i

R u R h P d

B

A l

G a

C

S i

G e

S n

P

O F

H e

N e

A r

K r

X e

C u

4

12

20 21 22 23 24 25 26 27 28 29 30 31

13

5

32

14

6

34

16

8

35

17

9

36

18

10

2

38 39 40 41 42 43 44 45 46 47 48 49 50 51 53 54

Li

Rb

Na

K

1

3

11

19

37


La57


Cs55

22

Co diffusion in CdZnTe

CdZnTe

Co diffusion enhanced by Cd atmosphere Box shaped Co profile

0 100 200 300 400 5001010

1011

1012

1013

1014

30 min: vacuum 60 min: Cd atmosphere

conc

entra

tion

(cm

-3)

depth (µm)

Co: 800 K

23

Co diffusion in CdZnTe

Te rich (p-type ): low mobility incorporation as CoCd ?

Cd rich (n-type): high mobility Co present as Coi

Coi negatively charged ?

0 200 400108

109

1010

1011

1012

1013

1014

conc

entra

tion

(cm

-3)

depth (µm)

0 100 200 300 400 5001010

1011

1012

1013

1014

30 min: vacuum 60 min: Cd atmosphere

conc

entra

tion

(cm

-3)

depth (µm)

Ag: 828 K

n pn p

Co: 800 K

24

n p

Ni diffusion in CdZnTe

Ni diffusion behaves similar to Co diffusion

CdZnTe

0 200 4001010

1011

1012

1013

1014

30 min: vacuum60 min: Cd amosphere

conc

entra

tion

(cm

-3)

depth (µm)

Ni: 800K

25

Summary

• Up hill diffusion for different elements• Up hill diffusion in different semiconductors

Ag

Ia

IIa

IIIb IV b V b V Ib V IIb V III Ib IIb


V III

Zn

Cd In

N

Sb

S

Se

Te

Cl

Br

I

As33

15

7

H

B e

M g

C a S c T i

S r Y

V C r M n

Z r N b M o T c

F e C o N i

R u R h P d

B

A l

G a

C

S i

G e

S n

P

O F

H e

N e

A r

K r

X e

C u

4

12

20 21 22 23 24 25 26 27 28 29 30 31

13

5

32

14

6

34

16

8

35

17

9

36

18

10

2

38 39 40 41 42 43 44 45 46 47 48 49 50 51 53 54

Li

Rb

Na

K

1

3

11

19

37


La57


Cs55

H. Wolf 1 , F. Wagner 1 , J. Kronenberg 1 , H. Wolf 1 , Th. Wichert 1 , K. Johnston 1

Documents

Transcript of H. Wolf 1 , F. Wagner 1 , J. Kronenberg 1 , H. Wolf 1 , Th. Wichert 1 , K. Johnston 1