OPTICAL-ABSORPTION EDGE OF SEMIINSULATING GAAS AND INP AT HIGH-TEMPERATURES

The temperature dependences of the optical absorption edges of semi-in sulating GaAs and InP have been measured from room temperature to 905 degrees C and 748 degrees C, respectively, with accuracies of +/-1 deg rees C at room temperature and +/-5 degrees C at 900 degrees C. The te mperature dependence of the optical absorption edge is adequately repr oduced by an Einstein model although the Varshni model gives an improv ed fit to the band gap. Finally, the widths of the absorption edges ar e correlated with ionicity. (C) 1997 American Institute of Physics.