Fabrication of High Efficiency Double Junction a-Si Solar Cells Using Amorphous and Microcrystalline SiO:H Films

摘要

We have developed amorphous and microcrystalline n-type SiO:H films by the RF-PECVD method (13.56 MHz). The films have characteristics suitable for use in the fabrication of multijunction a-Si solar cells. We have used n-μc-SiO:H film at the tunnel junction of a double junction (a-Si/a-Si) solar cell instead of the more conentional n-μc-Si:H films. Due to lower absorption of light the n-μc-SiO:H films the short circuit current of the cell is increased by ～4% and the overall increase in conversion efficiency is 3%. By using n-μc-SiO:H film at the tunnel junction and n-a-SiO:H film at the n-layer of the bottom cell the conversion efficiency is further increased ～3%. There is further scope of improving the conversion efficiency by using the materials developed by us.