Determination of the trap state density differences in hydrogenated microcrystalline silicon–germanium (Si:Ge:H) alloys

Time resolved photo-and thermoelectric effects (TTE) can be used to simultaneously determine, trap levels and trap state density differences in microcrystalline (μc-SiGe:H) samples. Here, in particular, the trap state density differences are obtained from the decay of the ambipolar charge distribution, i.e. stage II of the TTE transients. This type of spectroscopy has been applied for the first time to μc-SiGe:H samples and indeed trap states which seem to relate to concentration fluctuations, i.e. Si(Ge) and Ge(Si) clusters are observed.