Optical Output Power Enhancement of Gallium Nitride Light-Emitting Diodes with Microlens Array on p-GaN Layer and Wave-Patterned Sidewalls by Gas-Assisted Focused Ion Beam Etching

Abstract

By using iodine gas-assisted focused ion beam etching, a gallium nitride light-emitting diode with wave-patterned sidewalls and a microlens array on a p-GaN layer was successfully fabricated without an additional lithography process. The gallium nitride light-emitting diode after gas-assisted focused ion beam etching on the sidewalls and p-GaN layer shows 24% enhancement from the sidewalls and 53% from the top surface in optical output power with an operating voltage increase of 0.06 V at 20 mA.

Directional Difference of Patterns Printed by Scan-Projection Lithography Using a Gradient Index Lens Array

“…Optical microcomponents with large areas such as lens arrays are particularly required for various uses. For example, they are required for biomedical devices to realize artificial retinas, 1) real-time optical interconnections in optical computing and photonic switching circuits, 2,3) improving the efficiency of the optical head of an optical read-only-memory used for card systems, 4) collecting light rays at the aperture stops in an array for projection lithography, 5) optical communication devices including optical fiber coupling, 6) improving the light efficiency of liquid crystal display panels for projectors and threedimensional imaging, 7) enhancement of the optical output power of light-emitting diodes, 8) increasing the efficiency of ray convergence in image sensors, 9) optical multi-probes with a small spot size, 10) and variable focusing of a threedimensional display system. 11) Other than fabricating lens arrays, large resist patterns with widths from 100 m to 1 mm are often used for fabricating various large microfluidic devices.…”