Photoluminescence excitation spectra in amorphous: As₂S₃, As₂Se₃and selenium

Photoluminescence excitation spectra in chalcogenide glasses show a rapid fall-off in efficiency at high photon energies, which some authors attribute to surface recombination. This feature is discussed in the light of new experimental data, including luminescence in selenium. It is shown that surface recombination is an unlikely explanation and an excitation-energy dependent quantum efficiency must be assumed. The relationship between photoluminescence and photoconductivity is examined and an earlier model is developed in which the excitation spectrum is explained in terms of enhanced absorption near recombination centres.