Investigation of Al and PET flexible substrate effects on structural and optical properties of the absorber layer CIS

Due to the proper direct ban gap and high absorption coefficient of CuInS(CIS) absorber layer, this layers devoted much attention to itself. Beside of this, using of flexible substrates in solar cell fabrication, cause to increase the benefit of CIS usage. The solar cell based on CIS, due to their high conversion efficiency, their low cost potential and the many application possibilities are very attractive. They can be grown on metal or polymer substrate with a variety of deposition methods. The conversion efficiency depends on the choice of the substrates and of the processing technology. In this research, we prepare and characterize structural and optical properties of CIS absorber layers on Al and polymer as tow flexible substrate. As the results, by changing the substrate from Aluminum to Polymer, the crystalline size and strain of CIS layers were changed. These changes are probably related to coefficient of thermal expansion of Aluminum, polymer substrates and CIS layer. In addition, Aluminum substrate can decrease resistivity (increase conductivity) of CIS absorber layer.