Key Processing Technology Analysis And Performance Testfor Cu?In,Ga?Se₂ Thin Film Solar Cell

Cu?In,Ga?Se2?CIGS?thin film solar cell which belongs to the second generation of solar cells has the high light absorption coefficient,high efficiency,stable performance,strong corrosion resistance,good low-light performance and adjustable optical band gap,and is expected to become a promising large-scale use of thin film solar cell.Because of high material resource utilization and low-cost input,electrodeposition method is an important research direction for preparing CIGS thin film solar cell.However,electrodeposition method for preparing CIGS film material has some problems which are lack of the stable Mo back contact for electrodeposition and useful process technology for enhancing crystalline quality of CIGS thin film.Forced on these two problems,this paper has researched on the electrodeposited CIGS thin film cell around three processing systems which were the fabrication of Mo back contact,annealing and etching treatments for precursor and selenization process.First of all,based on the pulsed direct-current?DC?magnetron sputtering method,we have researched on the effect of the different sputtering pressures and film thicknesses on CIGS films,including electrical property,morphology characteristic,surface roughness,crystalline structure and stress variation.Throught the optimized experiments,The Mo back contact has a total film thickness of 1.5?m and sheet resistance of 0.1-0.15?/?,which satisfies the requirement of the electrical property and electrodeposition-selenization process.Secondly,based on the modified Mo surface morphology,we has researched on the effect of the different Mo surface profiles on the electrodeposited films of Cu/In/Ga,Cu-In-Ga precursor and CIGS thin films.It is found that the smooth Cu surface profile can enhance element interdiffusion in the precurs which further help to improve the uniform crystalline structure of CIGS film and increase the amount of Ga doped in the CIGS lattice structure.Threely,through the use of plasma etching treatment for Cu-In-Ga precursor,this paper has researched on the effect of the surface property of precursor on the CIGS film material and related device performance.It is found that no matter which of the plasma selenization and normal selenization processes is used,the moderate etched precursor is beneficial to enhance the quality of CIGS film and device performance.Lastly,this paper use the different annealing temperature treated Cu-In-Ga precursors into plasma selenization process,compared with normal selenization process,studying the growth of CIGS film and device performance.It is found that plasma selenization and annealing treatment processings both can help to reduce the CuInSe₂ and CuGaSe₂ adverse phase separation,increasing the crystalline quality of CIGS film.Because activated Se is more helpful to reduce phase separation,compared with element thermal diffusion,so plasma selenization has a more big influence on improving CIGS device performance.This paper also has researched on the growth mechanism of CIGS film based on the plasma selenization process with different substrate temperatures,and discussed the reaction routes of film growth.