Novel solar cell materials consisting of Si nanoparticles embedded in SiO2 layers have been studied using positron annihilation spectroscopy in Doppler broadening mode and photoluminescence. Two positron-trapping interface states are observed after high temperature annealing at 1100 °C. One of the states is attributed to the (SiO2/Si bulk) interface and the other to the interface between the Si nanoparticles and SiO2. A small reduction in positron trapping into these states is observed after annealing the samples in N2 atmosphere with 5% H2. Enhanced photoluminescence is also observed from the samples following this annealing step.
Journal of Applied Physics, 2013, Vol 114, Issue 16