Temperature Dependence of the Width of the Band Gap in Several Photoconductors

Abstract

The temperature dependence of the width of the forbidden band gap has been determined, between 90\ifmmode^\circ\else\textdegree\fi{} and 400\ifmmode^\circ\else\textdegree\fi{}K, for cadmium sulfide, cadmium selenide, cadmium telluride, and zinc selenide, by measurement of photosensitivity as a function of wavelength. The location of the maximum photosensitivity, often very sharp, at the wavelength corresponding approximately to the width of the band gap, makes this method very convenient for the determination. Structure exists in the photosensitivity maxima of cadmium sulfide and cadmium selenide, suggesting the existence of double conduction or valence bands.