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Micro-light-emitting-diodes (μLEDs) with size-independent peak external quantum efficiency behavior was demonstrated from 10 × 10 μm2 to 100 × 100 μm2 by employing a combination of chemical treatment and atomic-layer deposition (ALD) sidewall passivation. The chemical treatment and sidewall passivation improved the ideality factors of μLEDs from 3.4 to 2.5. The results from the combination of chemical treatment and ALD sidewall passivation suggest the issue of size dependent efficiency can be resolved with proper sidewall treatments after dry etching. [ABSTRACT FROM AUTHOR]

Length-controlled indium nitride (InN) nanowires are grown by localized laser-assisted metal organic vapor phase epitaxy. Laser irradiation results in spatially confined, rapid heating that enables precise nucleation control and subsequent nanowire growth. This localization of the laser-driven growth can realize on-demand and site-selective direct synthesis of length-controlled nanowires on catalytic gold nanodots. The length of the InN nanowires is controlled by the laser irradiation time at a fixed power. Energy dispersive X-ray, Raman and photoluminescence spectroscopic analyzes respectively characterize the elemental composition, crystallinity, and emission properties of as-grown InN nanowires. [ABSTRACT FROM AUTHOR]

Micro-light-emitting diodes (µLEDs) with tunnel junction (TJ) contacts were grown entirely by metalorganic chemical vapor deposition. A LED structure was grown, treated with UV ozone and hydrofluoric acid, and reloaded into the reactor for TJ regrowth. The silicon doping level of the n++-GaN TJ was varied to examine its effect on voltage. µLEDs from 2.5 × 10−5 to 0.01 mm2 in area were processed, and the voltage penalty of the TJ for the smallest µLED at 20 A/cm2 was 0.60 V relative to that for a standard LED with indium tin oxide. The peak external quantum efficiency of the TJ LED was 34%. [ABSTRACT FROM AUTHOR]

Ultrasmall blue InGaN micro-light-emitting diodes (µLEDs) with areas from 10−4 to 0.01 mm2 were fabricated to study their optical and electrical properties. The peak external quantum efficiencies (EQEs) of the smallest and largest µLEDs were 40.2 and 48.6%, respectively. The difference in EQE was from nonradiative recombination originating from etching damage. This decrease is less severe than that in red AlInGaP LEDs. The efficiency droop at 900 A/cm2 of the smallest µLED was 45.7%, compared with 56.0% for the largest, and was lower because of improved current spreading. These results show that ultrasmall µLEDs may be fabricated without a significant loss in optical or electrical performance. [ABSTRACT FROM AUTHOR]