Subquantum-Well Influence on Carrier Dynamics in High Efficiency DUV Dislocation-Free AlGaN/AlGaN-Based Multiple Quantum Wells
AuthorsAjia, Idris A.
Roqan, Iman S.
KAUST DepartmentAdvanced Semiconductor Laboratory
Computer, Electrical and Mathematical Sciences and Engineering (CEMSE) Division
Electrical Engineering Program
King Abdullah University of Science and Technology (KAUST), †Physical Science and Engineering (PSE) Division, §Computer, Electrical and Mathematical Sciences and Engineering (CEMSE) Division, and -1Imaging and Characterization Core Laboratory, Thuwal, Saudi Arabia
Material Science and Engineering Program
Physical Science and Engineering (PSE) Division
Semiconductor and Material Spectroscopy (SMS) Laboratory
KAUST Grant NumberBAS/1/1319-01-01
Online Publication Date2020-05-26
Print Publication Date2020-07-15
Permanent link to this recordhttp://hdl.handle.net/10754/664639
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AbstractWe explore the effect of the subwell centers and related carrier dynamics mechanisms in dislocation-free DUV AlGaN/AlGaN multiple quantum wells (MQWs) homoepitaxially grown on an AlN substrate. Cross-sectional imaging and energy-dispersive X-ray compositional analyses using scanning transmission electron microscopy (STEM) reveal epitaxial layers of very high crystalline quality, as well as ultrathin Al-rich subquantum barrier and subwell layers at the interface between the wells and the barriers. Carrier dynamic analyses studied by power- A nd temperature-dependent time-resolved and time-integrated photoluminescence (PL) and PL excitation measurements, as well as numerical simulations, reveal the carrier repopulation mechanisms between the MQWs and subwell sites. This advanced analysis shows that the subwell/sub-barrier structure results in additional exciton localization centers, enhancing the internal quantum efficiency via staggered carrier repopulation into the MQWs to reach a maximum of -83% internal quantum efficiency, which remains high at high injected carrier densities in the droop region. Both experimental and numerical simulation results show that the slight efficiency droop can be due to Auger recombination, counteracted by a simultaneous increase in radiative recombination processes at high power density, demonstrating the role of the subwells/sub-barriers in efficiency enhancement.
CitationAjia, I. A., Almalawi, D., Lu, Y., Lopatin, S., Li, X., Liu, Z., & Roqan, I. S. (2020). Subquantum-Well Influence on Carrier Dynamics in High Efficiency DUV Dislocation-Free AlGaN/AlGaN-Based Multiple Quantum Wells. ACS Photonics, 7(7), 1667–1675. doi:10.1021/acsphotonics.9b01814
SponsorsThe research reported in this publication was supported by funding from King Abdullah University of Science and Technology (KAUST), using the base funding (BAS/1/1319-01-01).
PublisherAmerican Chemical Society (ACS)