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Title: Enhanced UV detection by non-polar epitaxial GaN films

Nonpolar a-GaN (11-20) epilayers were grown on r-plane (1-102) sapphire substrates using plasma assisted molecular beam epitaxy. High resolution x-ray diffractometer confirmed the orientation of the grown film. Effect of the Ga/N ratio on the morphology and strain of a-GaN epilayers was compared and the best condition was obtained for the nitrogen flow of 1 sccm. Atomic force microscopy was used to analyze the surface morphology while the strain in the film was quantitatively measured using Raman spectroscopy and qualitatively analyzed by reciprocal space mapping technique. UV photo response of a-GaN film was measured after fabricating a metal-semiconductor-metal structure over the film with gold metal. The external quantum efficiency of the photodetectors fabricated in the (0002) polar and (11-20) nonpolar growth directions were compared in terms of responsivity and nonpolar GaN showed the best sensitivity at the cost of comparatively slow response time.
Authors:
; ; ;  [1] ;  [1] ;  [2] ;  [3]
  1. Materials Research Centre, Indian Institute of Science, Bangalore (India)
  2. (India)
  3. Department of Electrical Communication Engineering, Indian Institute of Science, Bangalore (India)
Publication Date:
OSTI Identifier:
22492237
Resource Type:
Journal Article
Resource Relation:
Journal Name: AIP Advances; Journal Volume: 5; Journal Issue: 12; Other Information: (c) 2015 Author(s); Country of input: International Atomic Energy Agency (IAEA)
Country of Publication:
United States
Language:
English
Subject:
36 MATERIALS SCIENCE; ATOMIC FORCE MICROSCOPY; COMPARATIVE EVALUATIONS; FILMS; GALLIUM NITRIDES; GOLD; MOLECULAR BEAM EPITAXY; MORPHOLOGY; NITROGEN; PHOTODETECTORS; QUANTUM EFFICIENCY; RAMAN SPECTROSCOPY; SAPPHIRE; SEMICONDUCTOR MATERIALS; STRAINS; SUBSTRATES; SURFACES; X-RAY DIFFRACTION