Temperature- and Excitation Power Density-Resolved Photoluminescence of AlGaN-Based Multiple Quantum Wells Emitting in the Spectral Range of 220-260 nm

Internal quantum efficiency (IQE) of AlGaN-based multiple quantum wells (MQWs) on face-to-face-annealed sputter-deposited AlN templates is examined by photoluminescence spectroscopy. The excitation power density dependence of IQE is evaluated as a function of temperature under the selective excitation of the quantum wells. The temperature dependences of the maximum IQE and the corresponding excitation power density (EPD) are analyzed based on the rate equation models for carriers and excitons. The decrease of the maximum IQE and increase of the corresponding EPD are mainly due to the increase in the nonradiative recombination rate via nonradiative recombination centers. Furthermore, the nonradiative recombination rate for the MQW with an emission wavelength around 220 nm is activated at a lower temperature than the other samples, which is expected to lead to the lower IQE of the MQW with an emission wavelength around 220 nm. Ultraviolet C-emitting AlGaN-based quantum well heterostructures are characterized by the excitation power density-resolved photoluminescence spectroscopy at different temperatures (10-295 K). The maximum internal quantum efficiency and the corresponding excitation power density are analyzed as a function of temperature. Both the temperature dependences are defined by the thermal activation of the Shockley-Read-Hall recombination rate.image (c) 2024 WILEY-VCH GmbH