An anomalous increase in the band-gap energy was observed in the temperature-dependent photoluminescence spectra of S-, Se- and Te-doped Ga0.68In0.32P. This blue-shift was attributed to a change in the many-body effect of the conduction electrons; due to electron capture at DX centers. The ratio of the electron concentration captured at the DX centers, to the free electron concentration, could be deduced from the values of the observed band-gap energy shifts. This ratio was equal to 0.40, 0.12 and 0.15 for S-, Se- and Te-doped samples, respectively.

N.Y.Lee, J.E.Kim, H.Y.Park, S.D.Kwon, H.K.Shin, H.Lim: Solid State Communications, 1997, 102[10], 763-7