Analysis of low temperature output parameters for investigation of silicon heterojunction solar cells

This paper presents an ASA simulation analysis of temperature dependent output parameters of the silicon heterojunction (SHJ) solar cell. The analysis has shown that low temperature behaviors of the open circuit voltage and fill factor are strongly connected with the presence of barriers for collection of photogenerated carriers in the SHJ structure. Previous experimentally observed saturation of the open circuit voltage at low temperature was attributed to the presence of a parasitic Schottky barrier at the transparent conductive oxide/amorphous emitter contact. A comprehensive simulation study is provided to describe the mechanism of such saturation and to define the conditions under which the saturation of the open circuit voltage can be used as relevant identification of the parasitic Schottky barrier in SHJ structures with both n-type and p-type amorphous emitters. In addition, the presented study provides the first guideline on the possible utilization of SHJ in low temperature applications such as space applications.