Study of 0.8 eV Deep Level Photoluminescence in Undoped LEC Semi-Insulating GaAs

Abstract

Detailed photoluminescence investigation was made on undoped LEC semi-insulating (SI) GaAs crystals in which a 0.8 eV deep emission band was dominantly observed. In crystals grown from the melt of different composition, intensity of the 0.8 eV band increased with increasing As fraction in the melt. Furthermore, in slightly Ga-rich crystals, it rapidly decreased at the tail of the boule with transition to a heavily Ga-rich condition. These results suggest that the 0.8 eV band is associated with a native point defect such as As_Ga antisite defect. In addition, more sensitive melt composition dependence of resistivity was observed in the 0.8 eV dominant crystals compared with those reported by Holmes et al. and by Ta et al.