Improved performance of AlGaInP red micro-light-emitting diodes with sidewall treatments

The electrical and optical improvements of AlGaInP micro-light-emitting diodes (mu LEDs) using atomic-layer deposition (ALD) sidewall passivation were demonstrated. Due to the high surface recombination velocity and minority carrier diffusion length of the AlGaInP material system, devices without sidewall passivation suffered from high leakage and severe drop in external quantum efficiency (EQE). By employing ALD sidewall treatments, the 20x20 mu m(2) mu LEDs resulted in greater light output power, size-independent leakage current density, and lower ideality factor. The forward current-voltage characteristic was enhanced by using surface pretreatment. Furthermore, ALD sidewall treatments recovered the EQE of the 20 x 20 mu m(2) devices more than 150%. This indicated that AlGaInP mu LEDs with ALD sidewall treatments can be used as the red emitter for full-color mu LED display applications. (C) 2020 Optical Society of America under the terms of the OSA Open Access Publishing Agreement.