Interpretation of an anomalous peak in low-temperature photoluminescence measurements of bulk GaAs[sub 1−x]N[sub x] on GaAs

• Main Authors: Cheah, Weng Kwong, Fan, Weijun, Yoon, Soon Fatt, Loke, Wan Khai, Liu, R., Wee, A. T. S.
• Other Authors: School of Electrical and Electronic Engineering
• Format: Article
• Language: English
• Published: 2013
• Subjects: DRNTU::Engineering::Electrical and electronic engineering
• Online Access: https://hdl.handle.net/10356/100683; http://hdl.handle.net/10220/17894
• Institution: Nanyang Technological University

Low-temperature 10 K photoluminescence measurements of GaAs1−xNx epitaxial layers grown on GaAs reveal an anomalous second peak in solid-source molecular beam epitaxy. Rapid thermal annealing RTA of a specific GaAsN sample reveals a lower energy peak which redshifts and a higher energy peak which blueshifts under increasing annealing temperature. The band-anticrossing model is used to identify the origins of the two peaks and we propose a model to explain the RTA observations by the concept of increased confinement in areas of higher N concentrations by trapped N localized states. The peak is due to the accumulation of N content near the GaAs/GaAsN interface. Hence, this abnormal annealing behavior occurs in layers with nonuniform N concentration at the GaAsN/GaAs interface.