Hetero-interface modification in thin film ZnO/Si solar cells

Thin film ZnO/Si heterojunction solar cells were explored for their potentially low cost application. Microcrystalline silicon (¿c-Si) deposited by metal induced growth (MIG) demonstrated viable photo response as a thin film base layer. Modeling using AMPS-1D was performed on various heterostructures. In thin film devices, Interface defects of 8.8×10¹¹ 1/cm²-eV were shown to significantly reduce fill factor and efficiency, while the addition of an a-Si interlayer diminished these effects and increased spectral response and the value of efficiency. Experimentally, the interlayer was implemented as sequential a-Si/nc-Si layers deposited by electron cyclotron resonance chemical vapor deposition (ECR-CVD). This was shown to improve conduction in ¿c-Si photodiodes and ZnO/p-Si heterojunctions. Upon a preliminary trial of implementing the complete thin film heterostructure, a diode behavior was observed despite a high leakage current that negated photo response.