PLD-produced thin films A3B5, A2B6, A6B4 and heterostructures based on them for IR detectors

Abstract

Results of investigations of thin-film heterojunctions nInSb–nGaAs, pInSb–nCdTe, thin films PbTe, Pb1−xSnxTe as well as periodic structures PbTe–Pba–PbTe produced by pulsed laser deposition (PLD) technique and possibilities of their application as IR photodetectors are discussed. PLD allows one to obtain abrupt interfaces of lattice-mismatched heterojunctions nInSb–nGaAs with large number of interface states. The sign reversal of photoresponse was observed in this structure in the wavelength range 3.5–6.5 µm. The wavelength at which the signal vanishes depends linearly on the applied bias voltage and shifts towards shorter wavelengths as the voltage increases. The device can operate as a sensitive null-signal detector and an infrared pyrometer. pInSb–nCdTe heterojunctions obtained by PLD in a regime of practically excluded interdiffusion of constituent materials reveal high sensitivity and fast operation (τ < 15 ns) in the spectral range 1.5–5.5 µm, which broadens with external voltage applied to the sample. This device can operate in photovoltaic, as well as in diode regimes. Optical memory effect was observed in heterojunction pInSb–nCdTe in the wavelength range 0.37–1.37 µm. PLD-produced PbTe, Pb1−xSnxTe films and periodic PbTe–Pba–PbTe structures with controllable parameters can be used as materials for detectors covering the wavelength range 1–10 µm.