Microcrystalline silicon solar cells deposited using a plasma process excited by tailored voltage waveforms

Thin film solar cells in a p-i-n structure with an absorbing layer of intrinsic hydrogenated microcrystalline silicon (mu c-Si: H) deposited through plasma enhanced chemical vapour deposition excited by tailored voltage waveforms have been prepared. The use of an asymmetric voltage waveform decouples the ion-bombardment energy at the growth surface from the injected power and allows the growth of good quality mu c-Si: H at reasonable deposition rates (3 angstrom/s) using low pressure, powder-free conditions. Unoptimized photovoltaic devices with an efficiency of 6.1% are demonstrated using an i-layer deposited at 1.3 angstrom/s and a process pressure of 500 mTorr. (C) 2012 American Institute of Physics. [http://dx.doi.org/10.1063/1.3699222]