Effect of thermal annealing on structural and optical properties of the GaAs_0.963Bi_0.037alloy

Abstract

We have investigated the effect of thermal annealing on GaAs 0.963 Bi 0.037 layers grown by atmospheric pressure metalorganic vapour phase epitaxy. High resolution x-ray diffraction (HRXRD) patterns show high crystalline quality and remarkable stability against thermal annealing up to 700 • C. When the annealing temperature reaches 750 • C, the GaAs 0.963 Bi 0.037 alloy is no longer stable, and the HRXRD pattern reveals the presence of other peaks. Atomic force microscopy images show a surface accumulation of Bi islands which disappear at 750 • C. The photoluminescence (PL) is clearly improved after annealing, but no shift of the PL peak was observed. The optimal annealing temperature is found to be ∼700 • C.

Novel Dilute Bismide, Epitaxy, Physical Properties and Device Application

“…There are a number of annealing studies reported and they are summarized in Table 5 below. Most previous reports focus on RTA of GaAsBi grown by both MBE [141,[143][144][145][146][147] and MOCVD [148,149]. The growth temperature used is between 200 and 420 • C measured by a thermocouple.…”

“…Moussa et al [148] reported RTA on 25-50 nm thick GaAs 0.963 Bi 0.037 grown by MOCVD. The XRD pattern shows no change up to 700 • C for 900 s while the 10 K PL reveals an enhancement of integrated PL intensity by more than 10 times and a reduction of FWHM from 126 meV to104 meV.…”

“…Unfortunately, the Bi-related localized defects in GaAsBi are hardly reduced by annealing method [150]. Although Moussa et al reported that the PL intensity of GaAsBi enhances about one order of magnitude with an annealing temperature of about 700 • C [148], they suggested that the PL intensity improvement is dominated by the reduction of non-Bi-related defects [145]. Nevertheless, GaAsBi laser diodes [248,249] and LEDs [250] have been realized, suggesting the promising application of dilute bismides on optoelectronic devices.…”

Variation of lattice constant and cluster formation in GaAsBi

“…[1][2][3][4][5][6][7][8][9][10] Adding small amounts of Bi to the GaAs lattice leads to a large reduction of the band gap, enabling access to important wavelengths in the infrared region. However, the successful incorporation of Bi within the GaAs lattice requires the use of unconventional growth procedures, such as growth temperatures near or below 400 C and a strict control of the As flux.…”

Effects of rapid thermal annealing on GaAs1-xBix alloys

“…9 The PL peak wavelength also blue-shifted by 8 meV which was attributed to the micro-scale changes inside the epilayer rather than Bi out diffusion. 9 For metal-organic vapor phase epitaxy (MOVPE) grown GaAs 1-x Bi x , PL intensity improvement of more than 10 times and full-width-at-half-maximum (FWHM) reduction of 23 meV were observed at 10 K. 10 Despite the significant improvements in Ref. 10, no PL emission could be detected above 100 K. Recently, photo-reflectance measurement performed by Chine et al shows that the band gap of GaAs 1-x Bi x was red-shifted by 60 meV after annealing at 600 C.…”