Minority carrier diffusion length is a key parameter of material quality and gives an indication of diode performance. It is also one important parameter when considering the increase of the effective optical sensitive area caused by the lateral diffusion and the crosstalk between individual detectors on a focal plane array (FPA). In this paper, we perform diffusion length measurements with two methods on short wavelength infrared (SWIR) HgCdTe photovoltaic devices. One method is based on the different behaviors of electrons and holes in a variation magnetic field B and their effects on the saturation current density J0. The other method is an optical characterization technique called Laser Beam Induced Current (LBIC). The results were in good agreement with each other.
Ion implantation enhanced intermixing of quantum well has become an important technology in device fabrication and material modification. We report the intermixing effect in a single asymmetric coupled quantum well (GaAs/AlGaAs) at different ion implantation dose by photoluminescence. More than 80meV of blue shift of the interband transition was observed <i>before</i> rapid thermal annealing process. It indicates that the intermixing has almost finished during the implantation process. A diffusion length of 1nm is obtained by the theoretical analysis.