Optoelectronic characterization of SiC with embedded Si nanocrystals as solar cell absorber material

An optoelectronic analysis of SiC with and without embedded silicon nanocrystals is presented. The layers are implemented as the absorber to membrane-based p-i-n solar cells and characterized by illumination-dependent IV measurements and electroluminescence. The silicon nanocrystals in silicon carbide were prepared by solid-phase crystallization and contacted with doped a-Si_xC_1-x:H. The fundamental transport and recombination properties, i.e. the effective mobility lifetime product, of the nanocrystal layer is determined at device level. For this means, illumination-dependent current-voltage curves are modeled with a voltage-dependent collection function with only two free parameters, and excellent agreement is found between theory and experiment. Electroluminescence measurements are presented and conclusions are drawn regarding the electronic structure of the SiC host matrix.