Thin-film Pb(0.9)Sn(0.1)Se photoconductive infrared detectors : photoconductivity measurements.
Holmquist, Kurt Ervin.
Tao, Tien Fau
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Pb(0.9)Sn(0.1)Se thin films were deposited on cleaved CaF(2) and BaF(2) substrates by vacuum evaporation methods. The as-deposited films were not photosensitive. Photoconductivity was observed after the films had been isothermally annealed in Pb-Sn rich vapor to reduce their carrier concentrations. Blackbody (500° K) response measurements were made to determine the responsivity and detectivity of the thin-film samples. Blackbody responsivities as high as 60 volts per watt were measured. Thin films with singlecrystal (lOO)-oriented structure were more sensitive than the films with either single-crystal (111) or polycrystalline mixed (111) and (100) structure. The wavelengths of photoconductive thresholds were determined by spectral response measurement and were in good agreement with the fundamental absorption edges. Photoconductive response times were measured using a GaAlAs heterojunction laser diode as the radiation source.