PHOTOLUMINESCENCE AND OPTICALLY DETECTED MAGNETIC-RESONANCE IN GEXS1-X SYSTEM GLASSES

The photoluminescence (PL) and optically detected magnetic resonance ( ODMR) of GexS1-x glasses from the whole glass-forming region (0.15 les s than or equal to x less than or equal to 0.44; T=2-8 K) were studied . Four broad bands (approximate to 0.3 eV) of PL with constant energie s (0.70, 0.86, 0.94, 1.08 eV) for all studied glasses were found when the excitation energy was lower than E(g)(opt). The intensities of ind ividual bands depend on composition, the integral PL intensity has a l ocal minimum for x=0.25 and a local maximum for x=0.44. The most inten sive is the band with E(PL)=1.08 eV. The ODMR spectra with g(1)=5.0, g (2)=2.7 and g=2.006 were found only in glasses with x>0.4. The g(1) an d g(2) values of ODMR bands are characteristic for S=1 triplet of exci ton, the g=2.006 corresponds to the value of an asymmetric ESR band of glasses with x>0.4. The explanation of a large Stokes shift is discus sed. The radiative recombination proceeds probably between intrinsic d efect states in the gap and tail states of the valence band.