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

Ramazan Atalay; Max Buegler; Sampath Gamage; M. K. Indika Senevirathna; Bahadir Küçükgök; Andrew G. Melton; Axel Hoffmann; A. G. Unil Perera; Ian T. Ferguson; Nikolaus Dietz

doi:10.1117/12.930199

15 October 2012 Effect of V/III molar ratio on the structural and optical properties of InN epilayers grown by HPCVD

Ramazan Atalay, Max Buegler, Sampath Gamage, M. K. Indika Senevirathna, Bahadir Küçükgök, Andrew G. Melton, Axel Hoffmann, A. G. Unil Perera, Ian T. Ferguson, Nikolaus Dietz

Author Affiliations +

Proceedings Volume 8484, Twelfth International Conference on Solid State Lighting and Fourth International Conference on White LEDs and Solid State Lighting; 84840X (2012) https://doi.org/10.1117/12.930199
Event: SPIE Optical Engineering + Applications, 2012, San Diego, California, United States

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 (n_e) and TO-phonon correlates with free carrier mobility (μ) in the InN epilayers.

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Ramazan Atalay, Max Buegler, Sampath Gamage, M. K. Indika Senevirathna, Bahadir Küçükgök, Andrew G. Melton, Axel Hoffmann, A. G. Unil Perera, Ian T. Ferguson, and Nikolaus Dietz "Effect of V/III molar ratio on the structural and optical properties of InN epilayers grown by HPCVD", 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); https://doi.org/10.1117/12.930199

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