Rapid thermal annealing effect on GaAsBi/GaAs single quantum wells grown by molecular beam epitaxy

Abstract

The effect of rapid thermal annealing on the optical and structural properties of GaAsBi/GaAs quantum wells (QWs) is investigated. The photoluminescence (PL) spectra of the samples are measured at 80 K and room temperature before and after rapid thermal annealing, to ascertain any improvement in the optical quality of the material. The impact of annealing temperature on QW interface quality, layer composition, and thicknesses are studied with x-ray diffraction. For a 60 second annealing time, the low temperature peak PL intensity increases to a maximum of 1.8 times the original intensity at an annealing temperature of 500 °C. Validating this optimum annealing temperature, the room temperature PL peak intensity is seen to increase by 2.2 times. The peak position exhibits a minor blueshift of 15 meV throughout the 450–700 °C temperature range, while annealing at 750 °C produces a blue-shift on the order of 100 meV, indicating out-diffusion of bismuth from the QW. Degradation of the QW interfaces with annealing temperatures above 550 °C is observed. The composition and thickness of the QWs remained constant up to 700 °C. Significant out-diffusion of bismuth and QW thinning are observed at an annealing temperature of 750 °C.