Open AccessDynamics of nonequilibrium carrier decay in AlGaN epitaxial layers with high aluminum content
Author(s) -
Tanuj Saxena,
M. S. Shur,
С. Наргелас,
Žydrūnas Podlipskas,
R. Aleksiejūnas,
Г. Тамулайтис,
M. Shatalov,
Jinwei Yang,
R. Gaška
Publication year - 2015
Publication title -
optics express
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.394
H-Index - 271
ISSN - 1094-4087
DOI - 10.1364/oe.23.019646
Subject(s) - photoluminescence , materials science , exciton , sapphire , non equilibrium thermodynamics , spontaneous emission , carrier lifetime , optoelectronics , charge carrier , molecular physics , condensed matter physics , optics , silicon , physics , laser , quantum mechanics
Carrier dynamics in high-Al-content AlGaN epilayers with different dislocation densities from 5 × 10(8) cm(-2) to 5 × 10(9) cm(-2) is studied by comparing the photoluminescence decay with the decay of carrier density. The carrier density decay was investigated using the light-induced transient grating technique. This comparison shows that the luminescence at the nonequilibrium carrier densities expected in operating light-emitting diodes depends on the recombination of free carriers and the localized exciton-like electron-hole pairs and localization-delocalization processes. In addition, a fraction of the nonequilibrium carriers is captured by the deep capture centers with extremely long lifetimes. These carriers have an insignificant contribution to the band-to-band radiative recombination. This capture is an important factor in decreasing the emission efficiency.