Extraction Efficiency Enhancement of GaN-Based Light-Emitting Diodes by Microhole Array and Roughened Surface Oxide

Abstract

The light-output power of GaN-based light-emitting diodes (LEDs) was enhanced by microhole array pattern and roughened GaO <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">x</sub> film grown on the exposed surface. The GaO <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">x</sub> film was grown by photoelectrochemical (PEC) oxidation via H <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sub> O and formed a naturally rough oxide surface and GaO <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">x</sub> /GaN interface. Compared with that of conventional broad-area LEDs, the output power of the microhole array LED and the surface-oxidized microhole array LED increased by 1.38 and 1.82 times at 20-mA forward current, respectively. The results show that the microhole array pattern with the roughened surface oxide method could significantly enhance light extraction efficiency and be a candidate for manufacturing high-efficient low-cost GaN-based LEDs.