Optimizing emitter-buffer layer stack thickness for p-type silicon heterojunction solar cells

p-type silicon heterojunction solar cells are investigated in terms of doping concentration of emitter a-Si: H(n) layer and thickness of emitter-intrinsic buffer a-Si: H(n/i) layers. Control of doping concentration of the amorphous layer is essential to gain sufficient conductivity and junction potential while avoiding an increase in defect density of the a-Si: H(n) layer. Inserting a-Si: H(i) provides high passivation quality by reducing a-Si: H/c-Si interface recombination and leads to a higher open circuit voltage. Properties and thicknesses of both a-Si: H(n) and a-Si: H(i) have a significant role on the performance of silicon heterojunction cell. In this paper, emitter a-Si: H(n) and buffer a-Si: H(i) layers thicknesses are optimized at the optimum gas phase doping concentration in order to obtain high efficiencies. (C) 2013 American Institute of Physics. [http://dx.doi.org/10.1063/1.4792510]