Temperature dependence of RoA product for PbSe photodiodes fabricated by MBE and diffusion.

The RoA product of PbSe photodiodes has been investigated experimentally and theoretically over a wide temperature region from 30 to 300 K. The photodiodes were made from PbSe bulk material by diffused and MBE techniques. Good agreement between experimental and theoretical results has been obtained. Evidence is presented that the RoA product is limited by depletion rather than diffusion (Auger recombination) at high temperatures, and at low temperatures by tunneling. Minority carrier lifetimes of the order of nanoseconds near room temperature are derived from a fit to experimental data, about 50 % shorter for MBE diodes than for diffused diodes. Majority carrier concentration profiles near the p-n junction at low temperatures are obtained based on the band to band tunneling model roughly 70 % higher for MBE diodes than that for diffused diodes, which is in reasonable accordance with Hall data.