Temperature-Dependent Transient Capacitance in InGaAs/InP-based Diodes Kiril Simov and Tim Gfroerer...
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Temperature-Dependent Transient Capacitance in InGaAs/InP-based Diodes Kiril Simov and Tim Gfroerer Davidson College Mark Wanlass NREL Supported by the American Chemical Society – Petroleum Research Fund
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Transcript of Temperature-Dependent Transient Capacitance in InGaAs/InP-based Diodes Kiril Simov and Tim Gfroerer...
Temperature-Dependent Transient Capacitance in InGaAs/InP-based Diodes
Kiril Simov and Tim GfroererDavidson CollegeMark Wanlass
NRELSupported by the American Chemical Society – Petroleum Research Fund
Motivation: Thermophotovoltaics
Photovoltaic
Cell
Heat Source
Blackbody Radiator
ThermalRadiation
BlackbodyRadiation
Experimental Setup
Computer with LabVIEW
Temp Controller
Pulse GeneratorCryostat with sample
Digital Scope(Tektronix)
(1)(2)
(3)
(4)
(5)
Oxford77K
Agilent
Capacitance meter (Boonton)
P-N Junction Depletion Layer with Bias
Depletion Layer With Bias
Depletion Layer
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P N+
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Typical Capture Data –Dependence on Pulse Length
-200 0 200 400 600 800
1E-3
0.01
0.1
Temp: 77KPulse Length:
10 s 30 s 100 s 200 s
Cap
acita
nce
Cha
nge
(a.u
.)
Time (s)
Capture Analysis
0 200 400 600-8
-7
-6
-5
-4
-3
avg
=111 +/- 2 s
T = 77K, Bias:-0.1V steady state-0.3V reverse bias
blue
= 109 s
red
=113 s
Ln (
Am
plitu
de o
f Tra
nsie
nt)
(a.
u.)
Pulse Length (us)
DNv
1
Holes: = 2.5 x 10-20 cm2
Electrons: = 7.5 x 10-21
cm2
Capture cross-section
-400 0 400 800 1200 1600
0.0
0.1
0.2
0.3
0.4Temp: 77K
700s pulse Exp Fit
Cfree
Ctrapped
Cap
acita
nce
Cha
nge
(a.u
.)
Time (s)
Number of Traps
DF
TT N
C
CN
~ 7 x 1015 cm-3
Typical Escape data – Dependence on Temperature
-100 0 100 200 300 400 500 600 700 800
-9
-6
-3
0
= 33 s = 51 s
= 123 s
L
n(
C )
(a
.u.)
Time(s)
77K 146K 156K
Escape Analysis
~ trap depth
75 80 85 90 954
6
8
10
12
Avg Ea: 0.30 +/- 0.02 eV
Escape Rate ~ A * e-Ea / kT
Ln (
Esc
ape
Rat
e) (
s-1)
Energy 1/kT (eV-1)
Bias ~ 0V -1V -2V
Conclusions A deep level has been detected The effective trap cross-section is ~10-20 cm2
The trap concentration is ~ 1016 cm-3
The depth of the level is ~ 0.30 eV Our results are consistent with sub-bandgap PL
from similar structures. Web links:
This talk: http://webphysics.davidson.edu/faculty/thg/talks-posters/MAR-04.pptPL poster: http://webphysics.davidson.edu/faculty/thg/talks-posters/SESAPS-03.ppt
Device Structure
p+ layer
n layerjunction
