Type-II band alignment of low-boron-content BGaN/GaN heterostructures. (7th June 2019)

• Record Type: Journal Article
• Authors: Mickevičius, J; Andrulevicius, M; Ligor, O; Kadys, A; Tomašiūnas, R; Tamulaitis, G; Pavelescu, E-M
• Is Part Of: Journal of physics. Volume 52:Number 32(2019)
• Publication Date: 2019-06-07
• Subjects: nitrides -- BGaN -- XPS -- band alignment -- optical properties -- photoluminescence; Physics -- Periodicals; 530
• DOI: 10.1088/1361-6463/ab2337
• Languages: English
• ISSNs: 0022-3727

Abstract

Abstract: The band offset parameters of low-boron-content BGaN/GaN heterojunctions have been studied using x-ray photoelectron spectroscopy (XPS) and photoluminescence (PL) in Bx Ga1−x N epilayers ( x ⩽ 0.043) grown on GaN/sapphire and AlN/sapphire templates. A staggered-gap (type-II) band alignment has been identified at the BGaN/GaN heterojunction by XPS. A study of the red shift of deep-level-related yellow PL band and the band gap shrinkage of BGaN epilayers with increasing boron content confirmed the type-II band alignment and enabled us to estimate that the ratio of the conduction-to-valence band discontinuity is 57:43. It is also shown that the band gap bowing of the BGaN alloy system is accommodated in the conduction band.