Balancing Carrier Cooling in InN/GaN Quantum Wells via Point Defect Engineering

Abstract

ABSTRACT Hot‐carrier cooling asymmetry is a fundamental bottleneck in polar III‐nitride quantum wells, driving electron leakage and limiting radiative efficiency in light‐emitting devices (LEDs). Here we uncover a defect‐enabled strategy to symmetrize carrier relaxation in InN/GaN quantum wells by engineering nitrogen vacancies (V N ) at the N‐polar (000‐1) interface. First‐principles calculations combined with ab initio nonadiabatic molecular dynamics reveal that pristine InN/GaN exhibits markedly slow electron cooling due to sparse conduction‐band states and weak electron‐phonon coupling, whereas holes relax rapidly. Interfacial V N introduces multiple localized electronic levels above the CBM that bridge the low‐density of states (DOS) gap, concurrently increasing local electronic‐state continuity and strengthening nonadiabatic (electron‐phonon) coupling. As a result, hot‐electron cooling is accelerated by up to ∼8‐times (from 9.22 to 1.05 ps), approaching balanced relaxation with holes (0.58 ps). Parameterized TCAD (Technology Computer‐Aided Design) simulations further illustrate that stronger phonon‐assisted scattering suppresses electron leakage in a simplified InN/GaN LED model. This work establishes point‐defect engineering as an effective pathway to control hot‐carrier relaxation and improve carrier balance in polar semiconductor heterostructures.