Effect of heat treatment on the 0.93, 1.0, and 1.28 ev luminescence bands in n-GaAs

Abstract

Heat treatment of n-GaAs leads to a disappearance near its surface of the 0.93 eV emission band and to an appearance of the 1.0 and 1.28 eV emission bands. In the GaAs interior the 1.0 eV emission band gradually shifts to lower energies (0.93 eV), only weakly changing its intensity, the intensity of the 1.28 eV emission band monotonically decreases. The shift of the 1.0 eV emission band is the result of a superposition of the 1.0 and 0.93 eV emission bands with different intensities: the 1.0 eV emission band is at maximum and the 0.93 eV emission band at minimum near GaAs surface, and the 1.0 eV emission band is at minimum and the 0.93 eV emission band at maximum in the GaAs interior. Evidence is presented that in n-GaAs the 0.93 eV radiative centres may be associated with the VGaVAs divacancy, and the 1.0 eV radiative centres, with substitutional copper atom–vacancy pairs (CuGaVAs). The 1.0 eV radiative centres are formed by filling a VGaVAs divacancy (the 0.93 eV radiative centre) by diffusing copper atoms; this explains the 1:1 correspondence between changes in the intensities of the 1.0 and 0.93 eV emission bands. [Russian Text Ignored.]