Optimization of band gap, thickness and carrier concentrations for the development of efficient microcrystalline silicon solar cells: A theoretical approach

Hydrogenated microcrystalline silicon (μc-Si:H) has superior properties than hydrogenated amorphous silicon (a-Si:H) but its photo conversion efficiency is lower than a-Si:H. This may be due to lack of understanding of basic structural parameters of μc-Si:H solar cells. Optimization of basic structural parameters such as band gap, thickness of p-, i- and n-layers, acceptor concentration ( N a ) and donor concentration ( N d ) can help improving efficiency of μc-Si:H solar cells. We report the optimization of these structural parameters using AFORS-HET simulation software and the optimized values of band gap of p-, i- and n-layers are found to be 1.5 eV, 1.4 eV and 1.5 eV and their thicknesses are found to be 5 nm, 2000 nm and 20 nm, respectively. The optimization of values of N a and N d are also performed and highest efficiency of ∼17% is realized at N a and N d of 10 20 cm −3 . This study will be useful to solve the issues associated with existing μc-Si:H solar cell technology and may help fabricating high efficiency μc-Si:H solar cells.