The Investigation Of Chemical Synthesis And Film Forming Of CdS

Copper Indium Gallium selenium (CuIn1-xGaxSe2, short as CIGS) thin film solar cell was one of the new thin film solar cells with development fastest in the last century to clean. CIS thin film has developed quickly since CIS solar cell first out at Bell Laboratories on 1974, the cell was research quickly. CIGS is a chalcopyrite structure and in direct band-gap semiconductor material with a handful of Ga adopted on CIS material. The scope of response spectrum from infrared to visible light of CIGS is broadening due to the content of gallium adjusted the thickness direction to form a gradient band gap, the short-wave photons is used effectively, the conversion efficiency will be greatly improved, so the CIGS is becoming the most promising thin film photovoltaic materials and research topic.In the CIGS thin film solar cell, ZnO thin film as the window direct contact with absorbing layer CIGS thin film, the conversion efficiency is not high, while adding a buffer layer, the conversion efficiency of the solar cell has greatly improved. Currently, II-VI compounds semiconductor CdS film are always used as the buffer layer, it is directly gap of n type semiconductor, the single crystal band gap is 2.42eV, its formed transition between absorption layer and window layer and reduces the gap bench and lattice lost, the value of conduction band edge dislocation will be adjusted, what is more, the quality of P-N knot and performance of thin film solar cell has improved. So, how to get a good performance of buffer layer is a hot spot.In this experiment, we prepared CdS thin film by using the CBD and electro-deposition. The CdS films were deposited on SLG from a chemical bath containing thiourea, cadmium acetate, ammonia and ammonium acetate as the complexing agents, the influence of cadmium concentration and thiourea concentration on structure and properties of CdS films had been investigated. Moreover, the influence of magnetic field on structure and properties of CdS films had been investigated researched. For the electro-deposition, the reaction medium and the electrolyte on structure and properties of CdS thin film also analyzed, and the mechanism of ED-CdS thin film with the system of elemental sulfur were proposed.The results indicated that:as the acetic cadmium concentration and sulfur ureaconcentration of increased, the grain of CdS thin film first increases then reduces, and the film having a H (002) Crystal plane referential growth, and films are compact, furthermore, the average transmission of thin film first increases then reduces, the best chemical composition is 6X 10"3 mol/L acetic cadmium,2×10-3 mol/L acetic ammonium and 1×10-2 mol/L sulfur urea, the grain of thin film were grown up with the magnetic field, and the film more compact, but the average transmission and band gap are decreased. The CdS thin film electrodeposited in aqueous solutions of Reline ionic liquids present a regular hexagonal, the film is compact, the grains are bigger than in water and Reline ionic liquids, with highest average transmittance and the band gap is maximum, while reducing the amount of CdCb, the content of cadmium and grain in CdS thin films are decreased, the properties of thin film are decreased also.