III-nitride micro-emitter arrays: development and applications

Abstract

III-nitride micro-emitter array technology was developed in the authors' laboratory around 1999. Since its inception, much progress has been made by several groups and the technology has led to the invention of several novel devices. This paper provides an overview on recent progress in single-chip ac-micro-size light emitting diodes (μLEDs) that can be plugged directly into standard high ac voltage power outlets, self-emissive microdisplays and interconnected μLEDs for boosting light emitting diodes's wall-plug efficiency, all of which were evolved from III-nitride micro-emitter array technology. Finally, potential applications of III-nitride visible micro-emitter arrays as a light source for DNA microarrays and future prospects of III-nitride deep ultraviolet micro-emitter arrays for label-free protein analysis in microarray format by taking advantage of the direct excitation of intrinsic protein fluorescence are discussed.

GaAs pillar array-based light emitting diodes fabricated by metal-assisted chemical etching

“…Larger enhancement is observed with increasing injection current, implying better current spreading with the pillar structure, analogous to the micropixel LED geometry. 42,43 It should be noted that improved current spreading in such geometries should also yield greater internal quantum efficiencies at high injection current densities. 44 Beyond 225 mA (equivalent to a current density of 1.4 A/cm 2 ), where intensity saturation was first noted, the EL intensity from the MacEtched nanopillar array exceeds the intensity measured from the planar stack by a factor of roughly 3.…”

Full-scale self-emissive blue and green microdisplays based on GaN micro-LED arrays

“…Since their inception [3][4][5][6][7] , µLED arrays based on III-nitride semiconductors have emerged as a promising technology for applications, including self-emissive microdisplays [5][6][7][8] , single-chip high voltage ACLEDs for solid-state lighting [9][10][11] , and light sources for optogenetic neuromodulation [12][13][14][15] . The InGaN-based µLED array has opened a new avenue for the multi-site photostimulation of neuron cells and offers the opportunity to probe biological neuron networks at the network level 13,14 .…”

Creating a desired lighting pattern with an LED array

“…This leads to new possibilities in optical microscopy, bio-sensing and chemical sensing, mask-free lithography and direct writing. [5][6][7][8] An arbitrary image can be the target light distribution of the LED array. However, the pixels in that image cannot be used directly as intensity weights, since light beams overlap between neighboring LEDs.…”