The Construction、Structure Optimization And PV Performance Research Of ZnO/Cu₂O Thin Film Solar Cells

The fast development of solar cell industry is promoted by the global warming and theimpending exhaustion of fossil fuels. Although silicon solar cells with high performance haveshared over ninty percent of the solar cell market, additional subsidies from nationalgovernment are still needed for their lardge-area utilization due to the high cost of powergeneration. A possible way to solve the contradiction between their performance and cost ofsilicon solar cells is to develop novel solar cells using nanomaterials and nanotechnology withnew characteristics, which is different to the trandational bulk or thin film cells. Inorganicoxides are usually green and abundant semiconductors and can be used to fabricate cheapsolar cells with low cost.In this thesis, as two kinds of typical oxide semiconductor, n-zinc oxide （ZnO） and p-cuprous oxide （Cu₂O） were adopted to fabricate different solar cells by electrochemicaldeposition （ECD）, which is a facile, low cost, and environmentally friendly growth method.The main research focus is the relation between the photovoltaic properties and theirmictrostructures of different solar cells. The primary conclusions are as follow.1. ZnO films and nanorods with high crystal quality were grown by ECD. Accordingly,ZnO nanotubes with very thin walls were obtained by chemical etching nanorods. Then threekinds of heterostructures composed of n-type ZnO film or nanorods or nanotubes coveredwith a p-type Cu₂O thin film were fabricated and the relation between the photovoltaicperformances and heterostructures of the solar cells were investigated.2. ZnO nanorods with different lengths and diameters were grown by optimizing the ECDcondations and their influence on the photovoltaic properties of ZnO（nanorod）/Cu₂O（film）heterostructure solar cells were studied by measuring the transmission and reflectance spectra.3. N-type Cu₂O films were obtained by ECD under an optimized growth condation and itsgrowth orientation can be tuned by deposition potential. Then high-quality PN homojunctionwere built using Cu₂O films which have the same growth orientation. The relation betweenfilm growth orientation, interface state density, and solar cells performance was clarified.4. P-type Cu₂O films with pyramid-like surface texture were grown by ECD. It was found that the Cu₂O film solar cells efficiency can be further improved by increasing the optical pathdue to the total reflection caused by surface texture at the interface.