Performance of PV HgCdTe arrays for 1-14-µm applications

Recent developments in HgCdTe epitaxial-growth techniques and device-surface passivation resulted in major performance improvements of photovoltaic infrared detectors. By utilizing CdTe substrates, thin HgCdTe layers are grown from the liquid phase with any desired composition, thereby yielding detector material with peak sensitivity that can be adjusted for a wavelength from 1 to 14 µm. Two approaches for junction formation are reported; implanted homojunction and double-layer heterojunction. Detectivity limited by background radiation (BLIP) is reported. Theoretically predicted values of are measured for diodes designed to cover the 1-3-, 3-5-, and 8-14-µm bands. The frequency and junction-bias dependence of the dark noise current are characterized at a level of 5 × 10^-15A/Hz^1/2. It is shown that the device performance at any wavelength and temperature of interest can be described in terms of generation-recombination (G-R) and diffusion of minority-carrier current mechanisms.