Subquantum-Well Influence on Carrier Dynamics in High Efficiency DUV Dislocation-Free AlGaN/AlGaN-Based Multiple Quantum Wells

• DOI: 10.1021/acsphotonics.9b01814
• Publication Date: 2020-05-26T21:25:47Z
• Authors: Idris A. Ajia; Dhiafallah Almalawi; Yi Lu; Sergei Lopatin; Xiaohang Li; Zhiqiang Liu; Iman S. Roqan
• Keywords: Auger effect; Quantum Efficiency; Carrier lifetime; Cathodoluminescence

We explore the effect of 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 energy-dispersive X-ray compositional analyses using scanning transmission electron microscopy (STEM) reveal epitaxial layers very high crystalline quality, as well ultrathin Al-rich subquantum barrier at interface between barriers. Carrier dynamic studied by power- temperature-dependent time-resolved time-integrated photoluminescence (PL) PL excitation measurements, numerical simulations, repopulation MQWs sites. This advanced analysis shows that subwell/sub-barrier structure results additional exciton localization centers, enhancing internal efficiency via staggered into to reach a maximum ∼83% efficiency, which remains injected densities droop region. Both experimental simulation show slight can be due Auger recombination, counteracted simultaneous increase radiative recombination processes power density, demonstrating role subwells/sub-barriers enhancement.