Excitonic emission dynamics in homoepitaxial AlN films studied using polarized and spatio-time-resolved cathodoluminescence measurements

Abstract

Excitonic emission dynamics in homoepitaxial AlN films grown on a freestanding substrate prepared by the physical-vapor-transport method were examined. Reflecting the low threading dislocation density (<104 cm−2), room-temperature cathodoluminescence intensity images mapped at the free A-exciton energy exhibited homogeneous contrasts. Low-temperature cathodoluminescence peaks at 6.0415 and 6.0287 eV, which were polarized parallel and perpendicular, respectively, to the c-axis, exhibited identical risetimes and short lifetimes; the latter coincided with the temporal delay of neutral donor-bound exciton emissions. These results support the assumption that the two peaks originate from the recombination of free A-excitons of irreducible representations Γ1 and Γ5, respectively.

Simulation of Nitride Semiconductor MOVPE

“…The bandgap of the AlXGa1-XN system covers 3.42 eV to 6.04 eV [27,44]. AlGaN materials are useful for UV-LEDs, UV-laser diodes, and electronic devices.…”

Analysis of the n-GaN electrochemical etching process and its mechanism in oxalic acid

“…Generally, III-nitride systems are notable for their high chemical and thermal stability, [1][2][3][4][5] wide tunable bandgap (0.67-6.04 eV) [6][7][8] and the possibility of their nanoscale processing [9][10][11][12] that make them a promising basis for solid-state lighting devices. Recent fabrication technology is a useful option to modify the structure of III-nitride systems to selectively etch excessively ndoped layers either for their complete destruction and li-off of the remaining structure 13,14 or for their porosication.…”

Passivation of Surface States in GaN by NiO Particles

“…They are widely used in light-emitting diodes (LEDs) [1,2] and lately in micro-LEDs [3,4] because of the possibility of tuning their emission wavelength based on the metallic stoichiometry of their active region. In addition, they also have adequate band edges positions to drive water splitting [5] and artificial photosynthesis reactions [6][7][8][9][10][11], which is one of the most stringent requirements for photocatalysts of those reactions. However, their poor chemical endurance when used in photoelectrochemical (PEC) cells is one of their major flaws, especially in alkaline electrolytes [12,13].…”