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Title: Structural and optical properties of low temperature grown AlN films on sapphire using helicon sputtering system

AlN thin films have been deposited directly on c-plane sapphire substrates at low temperatures by a helicon sputtering system. The structural quality of AlN epitaxial films was characterized by x-ray diffractometry and transmission electron microscopy. The films exhibit smooth surface with root-mean-square roughness as small as 0.7 nm evaluated by atomic force microscope. The optical transmittance spectra show a steep absorption edge at the wavelength of 200 nm and a high transmittance of over 80% in the visible range. The band-edge transition (6.30 eV) of AlN film was observed in the cathodoluminescence spectrum recorded at 11 K. The spectral response of metal–semiconductor–metal photodetectors constructed with AlN/sapphire reveals the peak responsivity at 200 nm and a UV/visible rejection ratio of about two orders of magnitude. The results of this low temperature deposition suggest the feasibility of the epitaxial growth of AlN on sapphire substrates and the incorporation of the AlN films in the surface acoustic wave devices and the optical devices at deep ultraviolet region.
Authors:
 [1] ;  [2] ; ; ; ;  [3] ;  [4]
  1. Department of Electrical Engineering, Chien Hsin University of Science and Technology, Chung-Li 32097, Taiwan (China)
  2. Department of Materials Science and Engineering, I-Shou University, Kao-Hsiung 84001, Taiwan (China)
  3. Department of Electronic Engineering, Chung Yuan Christian University, Chung-Li 32023, Taiwan (China)
  4. Department of Physics, National Sun Yat-sen University, Kao-Hsiung 80424, Taiwan (China)
Publication Date:
OSTI Identifier:
22392177
Resource Type:
Journal Article
Resource Relation:
Journal Name: Journal of Vacuum Science and Technology. A, Vacuum, Surfaces and Films; Journal Volume: 33; Journal Issue: 3; Other Information: (c) 2015 American Vacuum Society; Country of input: International Atomic Energy Agency (IAEA)
Country of Publication:
United States
Language:
English
Subject:
75 CONDENSED MATTER PHYSICS, SUPERCONDUCTIVITY AND SUPERFLUIDITY; ALUMINIUM NITRIDES; ATOMIC FORCE MICROSCOPY; CATHODOLUMINESCENCE; DEPOSITION; EPITAXY; METALS; OPTICAL PROPERTIES; PHOTODETECTORS; ROUGHNESS; SAPPHIRE; SEMICONDUCTOR MATERIALS; SPECTRAL RESPONSE; SPUTTERING; SUBSTRATES; SURFACES; TEMPERATURE RANGE 0000-0013 K; THIN FILMS; TRANSMISSION ELECTRON MICROSCOPY; X-RAY DIFFRACTION