Anti-Stokes luminescence in chromium-doped ZnSe

The results of comprehensive studies of photoluminescence, photoluminescence excitation, electron spin resonance, and photoconductivity of chromium-doped ZnSe are discussed. It is shown that the blue anti-Stokes luminescence of ZnSe:Cr is induced by the two-step ionization transitions of Cr in which the charge state of chromium is changed from 2+ to 1+ and from 1+ to 2+. We also propose that some cooperative processes can contribute to excitation of the anti-Stokes luminescence. The Auger-type energy transfer mechanism of the photoluminescence excitation is discussed.