Photoconductivity of CsBr Crystals Containing Color Centers

Abstract

The spectral distribution of photoconductivity has been investigated at liquid nitrogen and liquid helium temperatures both on additively colored and X-rayed CsBr. A peak is always found on the long wavelength side of the F band in the spectral distribution curve of ηω. Absorption bands which are located at 400 and 490 mµ at liquid nitrogen temperature are found to occur only when F centers are present. Absorption of photons in these bands gives rise to photocurrents. The two bands are interpreted as those like the L bands in NaCl-type alkali halides. At liquid helium temperature, fine structure is resolved in the region below 600 mµ. A band, which is photoconductive, is developed on the long wavelength side of the F band by optical bleaching of the F band at liquid nitrongen temperature.