As-related stability of the band gap temperature dependence in N-rich GaNAs

Abstract

GaNAs layers with a low As concentration (As ≤ 0.6%) have been grown by molecular beam epitaxy and studied by structural and optical methods. It has been observed that the incorporation of a small amount of As atoms into the GaN host leads to a significant reduction of the bandgap due to the formation of an As-related band above the valence band of the GaN host. The position of this band does not change with temperature, and therefore, a reduced temperature dependence of the bandgap is observed for As-diluted GaN compared to the pure GaN host, which is ∼40 meV vs ∼70 meV in the 10–295 K temperature range. The observed effect is explained within the band anticrossing model. It is expected that the reduced temperature dependence of the bandgap in As-diluted GaN can be utilized in lasers with improved thermal stability.