Highhyphen;quality epitaxial PbxSn1minus;xTe films have been obtained for the first time on Ge substrates. The films have been deposited employing a rf multicathode sputtering system capable of simultaneous and sequential sputtering at different rates from three different targets. Heteroepitaxial films of PbxSn1minus;xTe at substrate temperatures lower than the ones needed in conventional evaporation techniques have been obtained using NaCl and BaF2substrates. Using the cosputtering technique, it has been possible to obtainnhyphen;type andphyphen;type PbxSn1minus;xTe layers by controlling the quantity of excess metal, or tellurium, respectively. Electrical properties close to the best reported singlehyphen;crystal values have been measured. Middlehyphen;infrared detector arrays have been made using PbxSn1minus;xTe films deposited on silicon and germanium substrates since such substrates can easily incorporate the electronic readout elements for a completely integrated thermal imaging system. Peak detectivity values up to 2.4times;108cm Hz1sol;2sol;W have been measured in photoconductive epitaxial thin films. Polycrystalline films deposited on SiO2hyphen;covered Ge and Si substrates have shown exceptionally high responsivity values (480 Vsol;W). Peak detectivities,D*lgr;(8.5 mgr;, 800,1), higher than 109cm Hz1sol;2sol;W have been obtained with a 2pgr;hyphen;sr field of view at an operating temperatue of 77deg;K. Measurements of noise, responsivity, and detectivity of linear detector arrays are reported.
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