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Measurement of Second Order Susceptibilities of GaN and AlGaN

Published

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 AlxGa1-xN films and a bulk free-standing GaN platelet. The AlxGa1-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 AlxGa1-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

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 April 20, 2024)
Created February 28, 2005, Updated October 12, 2021