Explicit analytical modeling of the low frequency a-Si:H/c-Si heterojunction capacitance: Analysis and application to silicon heterojunction solar cells

Journal Article · Mon Sep 21 04:00:00 EDT 2015 · Journal of Applied Physics

DOI:https://doi.org/10.1063/1.4931150· OSTI ID:22489502

Maslova, O. ^[1]; Brézard-Oudot, A.; Gueunier-Farret, M. -E.; Alvarez, J.; Kleider, J. -P. ^[2]

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1. Keldysh Institute of Applied Mathematics, Russian Academy of Sciences, Miusskaya sq., 4, Moscow 125047 (Russian Federation)
2. GeePs (Group of electrical engineering of Paris), CNRS UMR 8507, CentraleSupélec, Univ Paris-Sud, Sorbonne Universités-UPMC Univ Paris 06, 11 rue Joliot-Curie, Plateau de Moulon, F-91192 Gif-sur-Yvette Cedex (France)

We develop a fully analytical model in order to describe the temperature dependence of the low frequency capacitance of heterojunctions between hydrogenated amorphous silicon (a-Si:H) and crystalline silicon (c-Si). We demonstrate that the slope of the capacitance-temperature (C-T) curve is strongly enhanced if the c-Si surface is under strong inversion conditions compared to the usually assumed depletion layer capacitance. We have extended our analytical model to integrate a very thin undoped (i) a-Si:H layer at the interface and the finite thickness of the doped a-Si:H layer that are used in high efficiency solar cells for the passivation of interface defects and to limit short circuit current losses. Finally, using our calculations, we analyze experimental data on high efficiency silicon heterojunction solar cells. The transition from the strong inversion limited behavior to the depletion layer behavior is discussed in terms of band offsets, density of states in a-Si:H, and work function of the indium tin oxide (ITO) front electrode. In particular, it is evidenced that strong inversion conditions prevail at the c-Si surface at high temperatures down to 250 K, which can only be reproduced if the ITO work function is larger than 4.7 eV.

• OSTI ID: 22489502
• Journal Information: Journal of Applied Physics, Journal Name: Journal of Applied Physics Journal Issue: 11 Vol. 118; ISSN JAPIAU; ISSN 0021-8979
• Country of Publication: United States
• Language: English

Related Subjects

71 CLASSICAL AND QUANTUM MECHANICS
GENERAL PHYSICS
75 CONDENSED MATTER PHYSICS
SUPERCONDUCTIVITY AND SUPERFLUIDITY
CAPACITANCE
CURRENTS
DENSITY OF STATES
DEPLETION LAYER
DOPED MATERIALS
ELECTRICAL FAULTS
ELECTRODES
HETEROJUNCTIONS
INDIUM
PASSIVATION
SILICON
SOLAR CELLS
TEMPERATURE DEPENDENCE
TEMPERATURE RANGE 0273-0400 K
TIN OXIDES
WORK FUNCTIONS