Measurement of Second Order Susceptibilities of GaN and AlGaN

Published

March 1, 2005

Author(s)

Norman Sanford, Albert Davydov, Denis V. Tsvetkov, Vladimir A. Dmitriev, Stacia Keller, Umesh Mishra, Steven P. DenBaars, S S. Park, J H. Han

Abstract

Rotational Maker fringes, scaled with respect to χ₁₁⁽²⁾ of crystalline quartz, were used to determine the nonlinear optical coefficients χ₃₁⁽²⁾ and χ₃₃⁽²⁾ for samples of thin Al_xGa_1-xN films and a bulk free-standing GaN platelet. The Al_xGa_1-xN samples, ranging in thickness ranged from roughly 0.5 to 2 υ, were grown by metal-organic chemical vapor deposition (MOCVD) and hydride vapor-phase epitaxy (HVPE) on (0001) sapphire substrates. The Al mole fractions x were 0, 0.419, 0.507, 0.618, 0.660, and 0.666, for the MOCVD-grown sample, and x = 0.279, 0.363, and 0.593 for the HVPE-grown samples. The free-standing bulk GaN consisted of a 226 υ thick HVPE-grown film removed from its growth substrate. For the Al_xGa_1-xN samples, the magnitudes of χ₃₁⁽²⁾ and χ₃₃⁽²⁾ decreased roughly linearly with increasing x and extrapolate to 0 for x = 1 . Furthermore, the constraint expected for a perfect wurtzite structure, namely χ₃₃⁽²⁾ = -2χ₃₁⁽²⁾, was seldom observed and the samples with x = 0.660 and x = 0.666 showed χ₃₁⁽²⁾ and χ₃₃⁽²⁾ having the same sign. These results are consistent with the theoretical studies of nonlinear susceptibilities for AlN and GaN performed by Chen, et al., Appl. Phys. Lett. 66, 1129 (1995). The thicker bulk GaN sample displayed a complex superposition of high- and low-frequency Maker fringes due to the multiple-pass interference of the pump and SHG beams and the nonlinear coefficients were consistent with those measured for the thin-film GaN sample.

Citation

Journal of Applied Physics

Volume

97

Issue

053512

Pub Type

Journals

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Keywords

AlGaN, GaN, III-nitrides, nonlinear optics

Citation

Sanford, N. , Davydov, A. , Tsvetkov, D. , Dmitriev, V. , Keller, S. , Mishra, U. , DenBaars, S. , Park, S. and Han, J. (2005), Measurement of Second Order Susceptibilities of GaN and AlGaN, Journal of Applied Physics, [online], https://tsapps.nist.gov/publication/get_pdf.cfm?pub_id=31510 (Accessed May 15, 2024)