H. W. Choi

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High-performance, two-dimensional arrays of parallel-addressed InGaN blue micro-light-emitting diodes (LEDs) with individual element diameters of 8, 12, and 20 /spl mu/m, respectively, and overall dimensions 490 /spl times/490 /spl mu/m, have been fabricated. In order to overcome the difficulty of interconnecting multiple device elements with sufficient(More)
We describe the fabrication and characterization of matrix-addressable microlight-emitting diode (micro-LED) arrays based on InGaN, having elemental diameter of 20 /spl mu/m and array size of up to 128 /spl times/ 96 elements. The introduction of a planar topology prior to contact metallization is an important processing step in advancing the performance of(More)
Matrix-addressable arrays of InGaN micro-light-emitting diodes with 128 /spl times/ 96 pixels and a resolution of 1200 dpi have been fabricated using a novel "sloped sidewall" process. The devices have been fabricated on InGaN blue and green wafers, emitting light at the wavelengths of 468 and 508 nm, respectively. A simple circuit, which enables the(More)
In this letter, the reliability of green InGaN-GaN light-emitting diodes (LEDs) has been analyzed by correlating the defect density of wafers with various device parameters, including leakage current, 1/<i>f</i> noise, and degradation rate. It was found that as the wavelength of green LEDs increases from 520 to 550 nm by increasing the indium content in the(More)
The fabrication and performance of an InGaN light-emitting diode (LED) array based on a microring device geometry is reported. This design has been adopted in order to increase the surface area for light extraction and to minimize losses due to internal reflections and reabsorption. Electrical characteristics of these devices are similar to those of a(More)
We report on white light-emitting diodes (LEDs) with a truncated-conical (TC) geometry produced by laser micromachining. A blue LED was shaped into a circular disc with 50°-inclined sidewall using a modified laser micromachining setup. A layer of Al was coated onto the inclined sidewall and the bottom surface to form an integrated reflector. Due to the(More)
Pentacene OTFTs with HfLaO or HfO<inf>2</inf> as gate dielectric were fabricated. The dielectrics were prepared by sputtering method and then annealed in NH<inf>3</inf> at 400 oC. The k value for the HfLaO and HfO<inf>2</inf> films amounted to 12.3 and 11.8 respectively. Both of the OTFTs could operate with a supply voltage of -5 V. The mobility of the OTFT(More)
We report on an integrated fiber-coupled bi-linear micro-light-emitting diode array, serving as a portable microdisplay system. The fiber bundle transforms the bi-linearly arranged optical signals from the emissive array into a 6-by-8 pixel microdisplay, offering a crisp and clear optical output. The pixel-to-pixel coupling arrangement ensures optical(More)
OTFTs with P3HT as organic semiconductor and HfTiO as gate dielectric have been studied in this work. The HfTiO dielectric film was prepared by RF sputtering of Hf and DC sputtering of Ti at room temperature. Subsequently, the dielectric film was annealed in an NH<inf>3</inf> or N<inf>2</inf> ambient at 200 &#x00B0;C. Then a layer of OTS was deposited by(More)