TY - JOUR
T1 - Theoretical analysis of effects of deep level, back contact, and absorber thickness on capacitance-voltage profiling of CdTe thin-film solar cells
AU - Li, Jian V.
AU - Halverson, Adam F.
AU - Sulima, Oleg V.
AU - Bansal, Shubhra
AU - Burst, James M.
AU - Barnes, Teresa M.
AU - Gessert, Timothy A.
AU - Levi, Dean H.
N1 - Funding Information:
This research is supported by the US Department of Energy under Contract no. DE-AC36-08GO28308 .
PY - 2012/5
Y1 - 2012/5
N2 - The apparent carrier density profile measured by the capacitancevoltage technique in CdTe thin-film solar cells frequently displays a distinctive U-shape. We show that, even assuming a uniform carrier density, such a U-shape may arise from deep levels, a non-ohmic back-contact, and a thin absorber, which are commonly present in practical CdTe thin-film solar cells. A thin CdTe absorber contributes to the right branch of the U-shape due to a punch-through effect at reverse or zero biases, when the CdTe absorber is nearly fully depleted. A rectifying back-contact contributes to both branches of the U-shape due to voltage sharing with the front junction under a forward bias and early punch-through under a reverse bias. Deep levels contribute to the right branch, but also raise the bottom of the U-shape, leading to an overestimate of carrier density.
AB - The apparent carrier density profile measured by the capacitancevoltage technique in CdTe thin-film solar cells frequently displays a distinctive U-shape. We show that, even assuming a uniform carrier density, such a U-shape may arise from deep levels, a non-ohmic back-contact, and a thin absorber, which are commonly present in practical CdTe thin-film solar cells. A thin CdTe absorber contributes to the right branch of the U-shape due to a punch-through effect at reverse or zero biases, when the CdTe absorber is nearly fully depleted. A rectifying back-contact contributes to both branches of the U-shape due to voltage sharing with the front junction under a forward bias and early punch-through under a reverse bias. Deep levels contribute to the right branch, but also raise the bottom of the U-shape, leading to an overestimate of carrier density.
UR - http://www.scopus.com/inward/record.url?scp=84862806424&partnerID=8YFLogxK
UR - http://www.scopus.com/inward/citedby.url?scp=84862806424&partnerID=8YFLogxK
U2 - 10.1016/j.solmat.2012.01.003
DO - 10.1016/j.solmat.2012.01.003
M3 - Article
AN - SCOPUS:84862806424
SN - 0927-0248
VL - 100
SP - 126
EP - 131
JO - Solar Energy Materials and Solar Cells
JF - Solar Energy Materials and Solar Cells
ER -
