Electrical Study of Si/PS/ZnO:In Solar Cell Structure

Indium doped zinc oxide (IZO) thin films have been grown on porous silicon, in order to develop solar cell structure, by rf-sputtering at room temperature using indium (4 at %) doped nanocrystalline powder previously synthesized by the sol-gel method. Such layers are polycrystalline with a hexagonal wurtzite structure with a thickness of about 400 nm and preferential orientation in (002) crystallographic direction. Electrical study under illumination reveals that this type of nanostructure is promising for solar cell application. By comparing Si/PS/IZO and Si/PS/ZnO/IZO structures, we illustrate a satisfactory photovoltaic conversion with these structures. Also we reveal that interposing an undoped ZnO layer leads to a degradation of PV parameters, specially the short-circuit current (Isc) was affected. In fact, Isc decreases from 3 mA to 0.8 mA by adding the undoped ZnO thin layer. The open circuit voltage is less affected. A decay of 30 mV was recorded. C-V analysis gave a carrier density of about 1016 cm-3 for both cells.