Temperature Dependent “S-Shaped” Photoluminescence Behavior of InGaN Nanolayers: Optoelectronic Implications in Harsh Environment

Temperature-dependent photoluminescence measurements are reported for n+- and n-type InGaN nanolayers grown by plasma-assisted molecular beam epitaxy (PAMBE) on AlN/n-Si (111) template. A temperature-dependent “S-shaped” behavior of the InGaN nanolayers above room temperature (up to 433 K) was observed and is explained using thermally activated redistribution model within a Gaussian distribution of localized states. Different parameters such as Huang–Rhys parameter (S), carrier recombination time (τr), and broadening parameter (σ) of Gaussian distribution for localized states have been derived for both n- and n+-type InGaN. It is interesting to note that the band gap shrinkage starts later for the case of n-type InGaN because of the dominance of higher localized states over electron–phonon interaction. This work opens a new avenue to advance the InGaN based light emitting devices for harsh environments.