Temperature Dependence of Edge Emission in Single-Crystal Cadmium Sulfide

The temperature dependence of the two series of edge emission lines in single-crystal CdS has been studied in the range of 4.2 to 350°K. The "blue" or short-wavelength lines persist to 350°K, and at least three bands are directly associated with the low-temperature lines. The shortest wavelength band has a peak at 5092 Å at 300°K and is associated with line ${B_1}^1$ of Pedrotti and Reynolds which appears at 4853 Å at 4.2°K. The slope of the curve of wavelength versus temperature of this line is quite linear in the temperature range 175 to 350°K with slope of 6×${10}^{-4\mathrm{}}$ eV/°K. At lower temperatures the slope becomes less and in the range 4.2 to 100°K is 2×${10}^{-4\mathrm{}}$ eV/°K. In the case of the green fluorescence, under stimulation by 250-keV electrons at a current of 5 μA/${\mathrm{cm}}^2$, there is a band with a peak intensity at 5490 Å at 300°K. At 77°K the peak intensity of this band is at 5250 Å. The intensity of the band is three orders of magnitude less at 300°K than at 77°K.