Substrate Dependent Growth of Microcrystalline Silicon

Silicon (Si) heterojunction solar cells with efficiencies approaching 24.7% are poised to replace Si diffused junction solar cells. To further improve their efficiency, microcrystalline Si (uc-Si) could replace the amorphous Si (a-Si) emitter layer, thus improving the effective doping and increasing transparency. This improvement in efficiency would come at little additional cost and could be accomplished by altering the plasma-enhanced chemical vapor deposition (PECVD) conditions. A uc-Si film was deposited on glass, a-Si, c-Si, silicon dioxide, and sapphire. When integrated over the AM 1.5G spectrum, the a-Si:H film absorbs 3 mA/cm(2) the 50% crystalline uc-Si:H film absorbs 1.7 mA/cm(2).