Photoluminescence and optical absorption in glassy As Se1−

Abstract The photoluminescence and optical absorption spectra in glassy As x Se 1− x with 0.08 ⩽ x ⩽ 0.40 are essentially independent of x . The PL spectra peak at approximately half the optical gap and the exponential slopes of the optical absorption edges are all approximately 75 meV. For x > 0.4, the PL peaks shift to higher energies, the widths of the PL spectra increase, and there is a strong component to the optical absorption well below the optical gap. Comparisons with ESR experiments in the As x S 1− x system suggest the possibility of two PL peaks. The second PL peak and the optical absorption below the optical band gap for x > 0.4 are attributed to the presence of As–As bonds.