K. Kusakabe et al., Characterization of overgrown GaN layers on nano-columns grown by RF-molecular beam epitaxy, JPN J A P 2, 40(3A), 2001, pp. L192-L194
We report on the successful growth of free-standing GaN films on (0001) sap
phire substrates by RF-molecular beam epitaxy. The kev to obtain unstrained
GaN layers is employing self-organized GaN nano-columns which involve an a
ir gap structure as a footing layer of overgrown GaN. The residual strain i
n overgrown GaN films is evaluated by measuring the lattice constant by X-r
ay diffraction. It is found that the c-axis length of overgrown GaN is esti
mated to be 5.1848 Angstrom. which is close to the value of strain-free GaN
even with a layer thickness of 2.7 mum. Overgrown GaN peeled arbitrarily f
rom GaN nano-columns is observed due to the cleaving process.