Structural and optical properties of n-type and p-type GaAs_(1−x)Bi _x thin films grown by molecular beam epitaxy on (311)B GaAs substrates

Abstract

In this paper, we report on the structural and optical properties of n-type Si-doped and p-type Be-doped GaAs(1−x)Bix thin films grown by molecular beam epitaxy on (311)B GaAs substrates with nominal Bi content x=5.4%. Similar samples without Bi were also grown for comparison purposes (n-type GaAs and p-type GaAs). X-ray diffraction, micro-Raman at room temperature, and photoluminescence (PL) measurements as a function of temperature and laser excitation power (PEXC) were performed to investigate their structural and optical properties. X-ray diffraction results revealed that the Bi incorporation in both n-type and p-type doped GaAsBi was similar, despite that the samples present remarkable differences in the number of Bi related defects, non-radiative centers and alloy disorder. Particularly, our results evidence that the Birelated defects in n-and p-doped GaAsBi alloys have important impact on the differences of their optical properties.