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.

MgZnO films were fabricated by the molecular precursor method (MPM) for their application as UV transparent electrodes. It was clarified that annealing under suitable conditions using an Ar gas flow is effective for the realization of c‐axis‐oriented MgZnO films in the time of a pyrolysis reaction. The resistivity of the Ga‐doped Mg0.1Zn0.9O film was 2.5 × 10‐2 Ω · cm. The resistivity of the c‐axis‐oriented MgZnO films was lower than that of polycrystalline films. This is due to the reduction of the potential barrier at the boundaries of the crystallites. The spontaneous polarization affects the potential barrier. The c‐axis orientation reduces the potential barrier along the deposition plane (© 2010 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)

MgZnO thin films were fabricated by the molecular precursor method (MPM) for the realization of cost‐effective near‐ultraviolet (UV) transparent electrodes for GaN‐based UV light‐emitting diodes (LEDs). The fabrication by MPM requires a common solution. It was clarified that ammonia aqueous is a common solvent for Mg, Zn and Ga precursors. MgZnO thin film was successfully fabricated on a quartz glass substrate using MgZnO precursor solution. The solid phase composition of Mg in the film is 40‐50% of its molar fraction in the liquid phase. The X‐ray diffraction patterns indicate the films have a hexagonal single phase, the same as in the case of ZnO. Ga doping of the MgZnO films enables their resistivity control. The possibility of applying MgZnO films for UV transparent electrodes on GaN‐based UV LEDs is discussed. (© 2009 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)

Microsize 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 (MOVPE). Schottky‐type (ST) 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 led to an increase in electroluminescent intensity. The internal optical absorption in the GaN layer of the GaN‐based ST‐LEDs was also estimated to be 75% of the emission light power. (© 2008 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)