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Title: Optical waveguiding properties into porous gallium nitride structures investigated by prism coupling technique

In order to modulate the refractive index and the birefringence of Gallium Nitride (GaN), we have developed a chemical etching method to perform porous structures. The aim of this research is to demonstrate that optical properties of GaN can be tuned by controlling the pores density. GaN films are prepared on sapphire by metal organic chemical vapor deposition and the microstructure is characterized by transmission electron microscopy, and scanning electron microscope analysis. Optical waveguide experiment is demonstrated here to determine the key properties as the ordinary (n{sub 0}) and extraordinary (n{sub e}) refractive indices of etched structures. We report here the dispersion of refractive index for porous GaN and compare it to the bulk material. We observe that the refractive index decreases when the porous density p is increased: results obtained at 0.975 μm have shown that the ordinary index n{sub 0} is 2.293 for a bulk layer and n{sub 0} is 2.285 for a pores density of 20%. This value corresponds to GaN layer with a pore size of 30 nm and inter-distance of 100 nm. The control of the refractive index into GaN is therefore fundamental for the design of active and passive optical devices.
Authors:
;  [1] ; ; ;  [2] ; ;  [3]
  1. Institute Electronics, Microelectronics and Nanotechnology (IEMN CNRS), University of Valenciennes, Villeneuve d'Ascq (France)
  2. Department of Physics, Chonnam National University, Gwangju 500-757 (Korea, Republic of)
  3. Department of Physics and KI for the NanoCentury, Korea Advanced Institute of Science and Technology (KAIST), Daejeon 305-701 (Korea, Republic of)
Publication Date:
OSTI Identifier:
22314481
Resource Type:
Journal Article
Resource Relation:
Journal Name: Applied Physics Letters; Journal Volume: 105; Journal Issue: 5; Other Information: (c) 2014 AIP Publishing LLC; Country of input: International Atomic Energy Agency (IAEA)
Country of Publication:
United States
Language:
English
Subject:
36 MATERIALS SCIENCE; 71 CLASSICAL AND QUANTUM MECHANICS, GENERAL PHYSICS; CHEMICAL VAPOR DEPOSITION; GALLIUM NITRIDES; OPTICS; ORGANOMETALLIC COMPOUNDS; POROUS MATERIALS; PRISMS; REFRACTIVE INDEX; SAPPHIRE; SCANNING ELECTRON MICROSCOPY; TRANSMISSION ELECTRON MICROSCOPY; WAVEGUIDES