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Proceedings Paper

Effect of V/III molar ratio on the structural and optical properties of InN epilayers grown by HPCVD
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Paper Abstract

The dependency of the structural and optoelectronic properties of InN thin films grown by high-pressure chemical vapor deposition technique on the group V/III molar precursor ratio has been studied. X-ray diffraction, Raman spectroscopy, and IR reflectance spectroscopy have been utilized to study local- and long-range structural ordering as well as optoelectronic properties of the InN epilayers grown on crystalline sapphire substrates. The investigated InN epilayers were grown with group V/III molar precursor ratio varying from 900 to 3600, while all other growth parameters were kept constant. For a group V/III precursor ratio of 2400, the full width-half maximum of the Raman E2(high) mode and XRD (0002) Bragg reflex exhibit minimums of 7.53 cm⁻¹ and 210 arcsec, respectively, with maximized grain size and reduced in-plane strain effect. FTIR data analysis reveals a growth rate of 120 nm/hr, a carrier mobility of 1020 cm²V⁻¹s⁻¹, and a free carrier concentration of 1.7×1018 cm⁻³ for a V/III ratio of 2400. The Raman analysis indicate that non-polar E2(high) mode position remains unaffected from a changing V/III ratio; whereas, polar A1(LO) mode position significantly changes with changing V/III ratio. Optical analysis also suggests that LO-phonon correlates with free carrier concentration (ne) and TO-phonon correlates with free carrier mobility (μ) in the InN epilayers.

Paper Details

Date Published: 15 October 2012
PDF: 8 pages
Proc. SPIE 8484, Twelfth International Conference on Solid State Lighting and Fourth International Conference on White LEDs and Solid State Lighting, 84840X (15 October 2012); doi: 10.1117/12.930199
Show Author Affiliations
Ramazan Atalay, Georgia State Univ. (United States)
Max Buegler, Georgia State Univ. (United States)
Technische Univ. Berlin (Germany)
Sampath Gamage, Georgia State Univ. (United States)
M. K. Indika Senevirathna, Georgia State Univ. (United States)
Bahadir Küçükgök, The Univ. of North Carolina at Charlotte (United States)
Andrew G. Melton, The Univ. of North Carolina at Charlotte (United States)
Axel Hoffmann, Technische Univ. Berlin (Germany)
A. G. Unil Perera, Georgia State Univ. (United States)
Ian T. Ferguson, The Univ. of North Carolina at Charlotte (United States)
Nikolaus Dietz, Georgia State Univ. (United States)


Published in SPIE Proceedings Vol. 8484:
Twelfth International Conference on Solid State Lighting and Fourth International Conference on White LEDs and Solid State Lighting
Matthew H. Kane; Christian Wetzel; Jian-Jang Huang; Ian T. Ferguson, Editor(s)

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