UC Santa Barbara

We report on the plasma-assisted molecular-beam epitaxy of Mg-doped (10 (1) over bar0) GaN on (10 (1) over bar0) 6H-SiC. Secondary ion mass spectroscopy measurements show the incorporation of Mg into the GaN films with an enhanced Mg incorporation under N-rich conditions relative to Ga-rich growth. Transport measurements of Mg-doped layers grown under Ga-rich conditions show hole concentrations in the range of p=1x10(18) to p=7x10(18) cm(-3) and a dependence between hole concentration and Mg beam equivalent pressure. An anisotropy in in-plane hole mobilities was observed, with the hole mobility parallel to [11 (2) over bar0] being higher than that parallel to [0001] for the same hole concentration. Mobilities parallel to [11 (2) over bar0] were as high as similar to 11.5 cm(2)/Vs (at p similar to 1.8 x 10(18) cm(-3)). (c) 2005 American Institute of Physics.