It emerges that LEDs properties are strongly impacted by intrinsic disorder induced by random In compositional fluctuations. They obviously impact the light emission spectrum and carrier mobilities. The quantitative evaluation of their impact in full heterostructures is made difficult by the extreme demand on computing resources when calculating solutions of the Schrödinger equation for a disordered 3D potential map. Calculations are then limited to small volumes and to the first few quantum states, not allowing for simulations of transport properties in full devices. It was recently shown in a simplified model that disorder can account for a turn-on voltage of LEDs smaller by 1V compared to standard simulations. We will present novel theoretical and modeling tools of disorder, namely the Filoche-Mayboroda 3D localization landscape theory, which from the original disordered energy map provides an effective potential which allows to use standard transport equations while accounting for microscopic disorder. We thus gain a deep understanding of various effects of disorder in nitride heterostructures on their electrical and optoelectronic properties. As a first application of the new tool we model our detailed measurements of the absorption edge of InGaN/GaN quantum wells with varying In composition. The tool is then applied to carrier transport in full LED structures. The effective potential increases current at a given bias voltage by accounting for two quantum effects of disorder, tunneling and confinement, which together smooth out potential discontinuities in the heterostructure. Quantum efficiency, Auger and leakage droop, ideality factor of the LED will be discussed.
Claude Weisbuch, "Impact of InGaN alloy disorder on LED properties (Conference Presentation)," Proc. SPIE 10104, Gallium Nitride Materials and Devices XII, 101040O (Presented at SPIE OPTO: January 31, 2017; Published: 19 April 2017); https://doi.org/10.1117/12.2250936.5391659235001.
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