A leading goal of solar cell development is to reduce the cost of solar cells; a widely used method to reach this purpose is to reduce the raw material costs by reducing the wafer thickness.This paper describes the investigation of the thermal behaviour of different thin solar cell structures, focusing on the thickness of the solar cell and variation of the photoactive layer, as wells as the analysis and the explanation of the resulted phenomena. SR measurements, temperature dependence generated in case of short circuit current, diffusion length and lifetime test are incorporated.