Comments for doi:10.1063/1.2338602

Plasma-assisted molecular beam epitaxial growth of Mg-doped, p-type and Si-doped, n-type m-plane GaN on 6H m-plane SiC is demonstrated. Phase-pure, m-plane GaN films exhibiting a large anisotropy in film mosaic (~0.2° full width at half maximum, x-ray rocking curve scan taken parallel to [11[overline 2]0] versus ~2° parallel to [0001]) were grown on m-plane SiC substrates. Maximum hole concentrations of ~7×1018 cm–3 were achieved with p-type conductivities as high as ~5 Omega–1 cm–1 without the presence of Mg-rich inclusions or inversion domains as viewed by cross-section transmission electron microscopy. Temperature dependent Hall effect measurements indicate that the Mg-related acceptor state in m-plane GaN is the same as that exhibited in c-plane GaN. Free electron concentrations as high as ~4×1018 cm–3 were measured in the Si-doped m-plane GaN with corresponding mobilities of ~500 cm2/V s measured parallel to the [11[overline 2]0] direction.