P-GaN layer was grown by metalorganic vapor phase epitaxy at 1000degreesC with an LT-deposited AlN buffer layer. Bis(cyclopentadienyl) magnesium was used as a dopant and trimethyindium (TMIn) was simultaneously Supplied. N-2 carrier gas was used during GaN growth. The contact of as-grown GaN:Mg sample was Ohmic only for III-doped GaN. Others showed Schottky behavior. The hole concentration was increased up to 5.0 x 10(17) cm(-3) at room temperature for In-doped samples. Moreover. with increasing TMIn flow rate. the biaxial strain in as-grown p-GaN was reduced and accordingly the hole concentration was increased. (C) 2002 Elsevier Science B.V. All rights reserved.