Silicon heterojunction solar cells: Analysis and basic understanding

Increasing the solar cell efficiency by applying advanced cell architectures is one route for crystalline silicon wafer based PV to achieve significant cost reduction. An elegant strategy to overcome the limiting losses of the currently dominating solar cell designs based on diffused homojunctions is the application of passivating and carrier selective contacts. They combine passivating buffer layers and suitable contact layers in an one dimensional thin films stack. The lack of knowledge regarding important operation principles and adequate characterization approaches for such novel contacts triggered this work. Besides a thorough understanding, several aspects of device optimization and characterization were addressed experimentally and via numerical simulation. Suitable characterization approaches, novel contact materials and novel cell designs were successfully established.