Using Measurements of Fill Factor at High Irradiance to Deduce Heterobarrier Band Offsets: Preprint
Using a 2D device simulation tool, we examine the high irradiance behavior of a single junction, GaAs concentrator cell as a function of the doping in the back surface confinement layer. The confinement layer is designed to be a barrier for both holes and electrons in the base of the solar cell. For a p-type base we show that the FF of the cell at high concentrations is a strong function of both the magnitude of the valence band offset and the doping level in the barrier. In short, for a given valence band offset (VBO), there is a critical barrier doping, below which the FF drops rapidly with lower doping. This behavior is confirmed experimentally for a GaInP/GaAs double heterostructure solar cell where the critical doping concentration (at 500 suns) in the back surface confinement layer is ~1e18 cm-3 for a VBO of 300 meV.
- Research Organization:
- National Renewable Energy Lab. (NREL), Golden, CO (United States)
- Sponsoring Organization:
- USDOE Office of Solar Energy Technologies Program
- DOE Contract Number:
- AC36-08GO28308
- OSTI ID:
- 1022411
- Report Number(s):
- NREL/CP-5200-50737; TRN: US201117%%845
- Resource Relation:
- Conference: Presented at the 37th IEEE Photovoltaic Specialists Conference (PVSC 37), 19-24 June 2011, Seattle, Washington
- Country of Publication:
- United States
- Language:
- English
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