Optical anisotropy of CuPt-ordered GaAsBi alloys. (22nd September 2021)

• Record Type: Journal Article
• Authors: Karpus, V; Čechavičius, B; Tumėnas, S; Stanionytė, S; Butkutė, R; Skapas, M; Paulauskas, T
• Is Part Of: Journal of physics. Volume 54:Number 50(2021)
• Publication Date: 2021-09-22
• Subjects: atomic ordering -- bismides -- optical anisotropy -- valence band splitting; Physics -- Periodicals; 530
• DOI: 10.1088/1361-6463/ac244a
• Languages: English
• ISSNs: 0022-3727

Abstract

Abstract: The molecular beam epitaxy-grown epitaxial, partially relaxed, GaAs 1 − x Bi x bismide layers of ∼ 1 μ m thickness and x ≍ 0.04 composition are examined. The atomic-structure analysis by x-ray diffraction and transmission electron microscopy shows the bismides to be CuPt B -type atomic-ordered in both B + and B − subvariants. The ordering induces an optical anisotropy, which manifests at normal incidence light-beam propagation. The anisotropy is revealed by various optical spectroscopy techniques—polarized photoluminescence, photo-modulated transmittance and reflectance, polarized transmittance, and spectroscopic ellipsometry. The ordering-induced valence band splitting, determined from modulation spectroscopy measurements, is of about 60 meV . The splitting is comparable to that in CuPt-ordered conventional III–V semiconductor alloys even though the maximal ordering parameter in investigated bismides is one order of magnitude lower.