Individually-addressable flip-chip AlInGaN micropixelated light emitting diode arrays with high continuous and nanosecond output power

Abstract

Micropixelated blue (470 nm) and ultraviolet (370 nm) AlInGaN light emitting diode ('micro-LED') arrays have been fabricated in flip-chip format with different pixel diameters (72 microm and 30 microm at, respectively, 100 and 278 pixels/mm(2)). Each micro-LED pixel can be individually-addressed and the devices possess a specially designed n-common contact incorporated to ensure uniform current injection and consequently uniform light emission across the array. The flip-chip micro-LEDs show, per pixel, high continuous output intensity of up to 0.55 microW/microm(2) (55 W/cm(2)) at an injection current density of 10 kA/cm(2) and can sustain continuous injection current densities of up to 12 kA/cm(2) before breakdown. We also demonstrate that nanosecond pulsed output operation of these devices with per pixel onaxis average peak intensity up to 2.9 microW/microm(2) (corresponding to energy of 45pJ per 22ns optical pulse) can be achieved. We investigate the pertinent performance characteristics of these arrays for micro-projection applications, including the prospect of integrated optical pumping of organic semiconductor lasers.

CMOS-Controlled Color-Tunable Smart Display

“…The low-indium-content blue QWs function as an electron reservoir and prestrain-relaxation layer for improving the radiative efficiency of the main QWs [16], [17]. The LED device used for the microdisplay demonstration was fabricated by using a similar process to that previously reported [18]. It consists of a 16 Â 16 array of individually addressable microdisk LED pixels with a diameter of 72 m on a 100-m center-tocenter pitch [see Fig.…”

Sub-Micron Lithography Using InGaN Micro-LEDs: Mask-Free Fabrication of LED Arrays

“…Feature sizes as small as 20 µm were obtained by using proximity exposure with micro-LEDs, while similar feature sizes have also been obtained using a broad-area LED source coupled to a microscope objective [5], [6]. The use of micro-LEDs brings the primary advantages of offering a large density of emitters on a small-scale chip, and a higher power density per pixel than broad-area LEDs [8].…”

Characteristics and applications of InGaN micro-light emitting diodes on Si substrates

“…These devices have some advantages over larger conventional LEDs, such as high modulation bandwidths [1], reduced device selfheating [2], and higher optical output power densities [3], and have been demonstrated for applications as diverse as visible-light communication (VLC) [1], [4], [5], microdisplays [6], opto-electronic trapping of cells [7] and maskfree photolithography [8].…”