Recovering the efficiency of AlGaInP red micro-LEDs using sidewall treatments

Abstract

Abstract A sidewall treatment process is proposed to recover the external quantum efficiency (EQE) loss in AlGaInP micro-LEDs (μLEDs). The proposed sidewall treatment consists of thermal annealing, ammonium sulfide chemical treatment, and sidewall passivation using atomic-layer deposition (ALD). The devices with sidewall treatment show improved optical power of more than 500% and 190% at 5 and 100 A cm−2, respectively, compared to devices with ALD sidewall passivation. The reduction in EQE was 20% when shrinking the device dimensions from 100 × 100 to 20 × 20 μm2. This work reveals that AlGaInP μLEDs can be energy efficient by employing proper sidewall treatments.