Novel Process Flow and Cell Architecture for 10 μm Thick Membrane Single-crystalline Silicon Solar Cell

Ultra-thin single-crystalline (sc-Si) solar cells are one possible route towards the goal of low-cost high-efficiency photovoltaics. The main motivation for such solar cells is cost reduction due to the drastic reduction of high-purity silicon required for fabrication. This reduction is typically an order of magnitude from that of conventional cells, while still maintaining a reasonable efficiency. In this work, novel ultra-thin solar cells were fabricated on a large-area 10 μm thick sc-Si free standing membrane using a novel lithography-free laboratory process that is simpler and more versatile than that reported elsewhere. The procedure allows for high temperature front and rear-side processing and is ideal as a base process flow for further investigation of ultra-thin sc-Si cells. The initial un-optimized solar cell fabricated using this process flow achieved an efficiency of 6.6% via a fill factor of 0.71, a short circuit current of 17.0 mA cm−2 and an open circuit voltage of 0.54 V. Further improvements are anticipated with the incorporation of an anti reflection coating, thin film surface passivation and a rear reflector or surface texture.