Time-resolved photoluminescence studies of AlxGa1−xN alloys

Abstract

The optical properties of AlxGa1−xN alloys with x varied from 0 to 0.35 have been investigated by picosecond time-resolved photoluminescence (PL) spectroscopy. Our results revealed that while the PL intensity decreases with an increase of Al content, the low-temperature PL decay lifetime increases with Al content. These results can be understood in terms of the effects of tail states in the density of states due to alloy fluctuation in the AlxGa1−xN alloys. The Al-content dependence of the energy-tail-state distribution parameter E0, which is an important parameter for determining optical and electrical properties of the AlGaN alloys, has been obtained experimentally. The PL decay lifetime increases with the localization energy and, consequently, increases with Al content. The implications of our findings to III-nitride optoelectronic device applications are also discussed.

Raman Spectroscopy and Time-Resolved Photoluminescence of BN and BxCyNz Nanotubes

“…It can be seen that both lifetimes increase on the lower energy shoulder of the PL peak. This is typical band-edge luminescence behavior in which the shorter lifetime of higher-energy carriers is attributed to the additional relaxation channel via thermalization to lower-energy states [15].…”

Dependence of carrier localization in InGaN∕GaN multiple-quantum wells on well thickness

“…14,15 However, these results point out that an increase of potential fluctuations can occur with well thickness as well. Previously, several reports suggested that the localized states may arise from In compositional fluctuation or QD formation, phase separation, monolayer thickness fluctuation, and surface segregation.…”

The Effect of Trimethylaluminum Flow Rate on the Structure and Optical Properties of AlInGaN Quaternary Epilayers

“…This situation is unlike the traditional AlGaN alloys. For AlGaN ternary alloys, the near band emission usually gets weaker as the Al content increases [18]. In III-N based materials, the misfit dislocation normally plays the role of nonradiative recombination centers [19], the higher Al content causes larger lattice mismatch between the GaN buffer and AlGaN, leading to a higher number of defects which results in weaker emission intensity [20].…”