Second harmonic generation in GaN/Al50Ga50N films deposited by metal-organic chemical vapor deposition

Second harmonic generation was observed experimentally from GaN/Al50Ga50N multilayers grown on sapphire substrate by means of the rotational Maker fringe technique at a fundamental beam wavelength of 1064 nm. From a single thick GaN layer (302 nm), the d(33) of GaN was evaluated and compared to the nonlinear coefficient obtained from measurements on several thin multilayer samples. Results show that the process of growing several thin, alternating layers does not cause the deterioration of the effective nonlinear susceptibility, which is 4.82 pm/V for GaN and 1.20 pm/V for Al50Ga50N, consistent with known values obtained for thick substrates. (c) 2006 American Institute of Physics.