Fabrication of GaN-based metal-oxide-semiconductor light-emitting diodes operating in ultraviolet spectral region

Abstract

Integrated light-emitting diodes (LEDs) that operate in the UV spectral region were fabricated using GaN layers grown on sapphire substrates by metal-organic vapor phase epitaxy. Schottky-type LEDs and metal-oxide-semiconductor (MOS) LEDs were realized. The near-band-edge emission of GaN was observed in the electroluminescent spectra with reversed bias under pulsed-voltage conditions. The insertion of an aluminum oxide layer in the GaN-based LED leads to an increase in electroluminescent intensity.

Fabrication of GaN‐based Schottky‐type light‐emitting diodes for micropixels in flat‐panel displays

“…In the GaN layers, no emission centers, such as rare-earth atoms, were introduced. Thus, the light emission occurred in the flat-band position near the depletion layer [5]. The wave packets of the emitted light are generated near the electrode.…”

“…The aluminum oxide layer was obtained from a vacuum-evaporated aluminum film, which was patterned on the GaN layer, then oxidized in air at 450 °C. X-ray photoelectron spectroscopy (XPS) spectra indicate that the layer was oxidized to Al 2 O 3 [5]. The thickness of the Al film was 20 nm, and its resistivity was 13 nΩ･cm, which became 1.2 kΩ･cm upon oxidation.…”

“…We consider that the light-emission mechanism is based on impact ionization caused by hot electrons [5,6]. In the GaN layers, no emission centers, such as rare-earth atoms, were introduced.…”

“…ST-LEDs operating in the UV spectral region were fabricated using an Al/Au large electrode and Au small electrodes. Their patterns were formed by screen printing and the lift-off technique [5]. The lift-off was performed in acetone.…”

Fabrication of MgZnO films by molecular precursor method and their application to UV‐transparent electrodes

“…2, indicate that the composition of Mg x Zn 1-x O should be determined in accordance with its excitonic absorption shape. For example, the Mg composition will be over 10% for the fabrication of MgZnO-based transparent electrodes on GaN-based LED operating in the spectral range of approximately 370 nm [9]. The MgZnO films whose Mg compositions over 10% could be fabricated by MPM.…”