Ultra-Thin Monocrystalline Silicon Solar Cell with 12.2% Efficiency Using Silicon-On-Insulator Substrate

Single side heterojunction silicon solar cells were designed and fabricated using Silicon-On-Insulator (SOI) substrate. The TCAD software was used to simulate the effect of silicon layer thickness, doping concentration and the series resistance. A 10.5 μm thick monocrystalline silicon layer was epitaxially grown on the SOI with boron doping concentration of 2×10¹⁶ cm⁻³ by thermal CVD. Very high V _OC of 678 mV was achieved by applying amorphous silicon heterojunction emitter on the front surface. The single cell efficiency of 12.2% was achieved without any light trapping structures. The rear surface recombination and the series resistance are the main limiting factors for the cell efficiency in addition to the c-Si thickness. By integrating an efficient light trapping scheme and further optimizing fabrication process, higher efficiency of 14.0% is expected for this type of cells. It can be applied to integrated circuits on a monolithic chip to meet the requirements of energy autonomous systems.