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Finite element simulations of compositionally graded InGaN solar
cells G.F. Brown a,b,* , J.W.AgerIIIb, W.Walukiewicz b, J.Wua,b,a
Advisor: H.C. KuoReporter: H.W. Wang
Solar Energy Materials & Solar Cells 94 (2010) 478–483
a Department of Materials Science&Engineering , University of California , Berkeley,California94720,USAb Materials Sciences Division , Lawrence Berkeley National Laboratory , Berkeley,California94720,USA
1. Introduction
2. Properties of InxGa1-xN used in simulations
3. Simulation results
Outline:
4. Conclusions
Broad band
InN - 0.7eV GaN - 3.42eV
Cheep fabrication process Grown on Si substrates by a low temperature
processHigh effiency
Advantage
DisadvantageIndium composition (<30%)
P-type doping
High absorption
Large lattice mismatch between InN and GaN alloysValence band discontinuity
Introduction
APSYS simulation tool
Self-consistancePoisson equationCarrier drift diffusion equation
InGaN - wurtzite crystal structure
Fermi level at the InGaN/GaN - un-pinned
No reflection and light trapping effects
No surface recombination losses
p-GaN
n-In0.5Ga0.5N
100nm
1mm
AM 1.5
5x1018cm-
3
1x1017cm-3
50nm1x1017cm-3
n-InXGa1-XN
Band diagram
Efficiency
p-GaN
n-In0.5Ga0.5N
100nm
1mm
AM 1.5
5x1018cm-
3
1x1017cm-3
50nm1x1017cm-3
n-InXGa1-XN
Minority hole life time in InGaN layer
p-GaN
n-In0.5Ga0.5N
100nm
1mm
AM 1.5
5x1018cm-
3
1x1017cm-3
50nm1x1017cm-3
n-InXGa1-XN
p-Si
n-Si
n-Si
5x1019cm-
3
1x1016cm-3
1x1019cm-3
100nm
495mm
5mm
Efficiency