Experimental study of the hot-carrier impact ionization photovoltaic effect in pulsed CO2-laser-excited silicon junctions

An experimental study has been carried out on the dependence of the hot-car rier highly nonlinear photovoltaic effect induced in silicon n(+)/p junctio ns by 10.6 mum laser pulses on the doping level and the carrier density pro file. The measured response is optimized by using narrow step junctions and a high doping level n(+) approximate to 10(20) cm(-3) The main features of the obtained results can be qualitatively interpreted by taking the follow ing into account: conditions for a thermalized hot-carrier plasma, generati on rate by impact ionization processes, generated minority diffusion curren t and recombination and absorption losses.