Fabrication of GaN‐based electroluminescent devices on Al substrates and their application to red, green and blue pixels for flat‐panel displays

Abstract

PACS 78.60. Fi, 81.05.Ea, 81.15.Hi, 85.60.Jb GaN-based thin-film electroluminescent devices (TF-ELDs) operating in the UV spectral region were fabricated on Al substrates. GaN films were deposited by compound-source molecular beam epitaxy (CS-MBE) technique. During the deposition, the cell temperature of the GaN compound source is one of the key factors for reducing the excess Ga in the films. The UV light emission (peak wavelength 375 nm) corresponding to the near-band-edge emission of hexagonal GaN was observed from GaN-based TF-ELDs. Furthermore, red, green and blue (RGB) lighting pixels were fabricated using UV GaN-based TF-ELDs in combination with RGB phosphors. GaN deposited at low temperature on low-cost substrates, such as silica glass and aluminum, is effective for low-cost fabrication requirement. Compound-source molecular beam epitaxy (CS-MBE) [1] was very useful for low-temperature deposition [2]. GaN powder is used as a source and no additional nitrogen source is introduced. Although the molecular species created during the deposition are unknown at present, some GaN is sublimated and some is decomposed [2]. The reduction of excess Ga is one of the crucial issues for the deposition of GaN by CS-MBE technique [3].In this study, GaN-based thin-film electroluminescent devices (TF-ELDs) operating in UV spectral region and fabricated on Al substrates are reported. We find that the cell temperature of the GaN compound source is one of the key factors for reducing the excess Ga in the films during the deposition. We also propose red, green and blue (RGB) pixels fabricated on GaN-based TF-ELDs for excitation by UV light emissions.