Evolution of Amorphous/Microcrystalline Silicon Tandem Solar Cells

Thin-film silicon solar cells are known to be able to improve the conversion efficiency of multijunction solar cells with different band gap. Amorphous silicon (a-Si) and microcrystalline silicon (mc-Si) double junction thin-film solar cells can be obtained conversion efficiency of more than 9% and be significantly improved conversion efficiency compared to a-Si single junction thin-film solar cells. Last year, ULVAC released the new PECVD system named CIM-1400 for mc-Si deposition with the concept of high-throughput and low-cost production, and developed a-Si/mc-Si tandem turnkey line. ULVAC realized tandem junction solar module with initial power output of 150W and stabilized power output of 135W produced with CIM-1400. ULVAC introduces its further approach to efficiency improvement of thin-film solar cell. Topics to be introduced are ULVAC’s approach to stabilized output 145W on commercial production basis, film configuration of a-Si/mc-Si tandem junction solar module and optimization results with a-Si deposition system (CCV-1400) and CIM-1400 as well as development progress of tandem junction solar module.