Characteristics of semiconductor alloy GaAs1-xBix

The characteristics of GaAs1-xBix semiconductor alloy layers grown by metalorganic vapor phase epitaxy (MOVPE) have been studied. GaAs1-xBix epilayers were obtained on GaAs substrates. The lattice constants of the alloy were found to increase with the addition of Bi. The uniformity and the reproducibility of the solid composition of the GaAs1-xBix epilayers are good in spite of the difficulty of epitaxial growth. Although layer growth was per-formed at a low temperature (365degreesC), the stability of GaAs1-xBix alloy was sufficient for device processing, which was demonstrated by annealing in an arsenic atmosphere at 560degreesC for 30 min. The photoluminescence (PL) spectra show that the PL peak energy of the GaAs1-xBix alloy shifts to a longer wavelength with increasing Bi content. The temperature dependence of the PL peak energy is much weaker than the temperature variation of the band gap of GaAs: the temperature dependence of the PL peak energy of the GaAS(0.974)Bi(0.026) layer is less than one-third the temperature variation of the band gap of GaAs. The results obtained in this research support the hypothesis that III-V alloy semiconductors consisting of semiconductor and semimetal components have a temperature-insensitive band gap.