As-doped p-type ZnO produced by an evaporation/sputtering process

Strongly p-type ZnO is produced by the following sequence of steps: (1) evaporation of Zn3As2 on a fused-quartz substrate at 350degreesC; and (2) sputtering of ZnO with substrate held at 450degreesC. The electrical characteristics include: resistivity of 0.4 Omega cm, a mobility of 4 cm(2)/V s, and a hole concentration of about 4x10(18) cm(-3). This resistivity is among the best (lowest) ever reported for p-type ZnO. Secondary-ion mass spectroscopic analysis gives an average As concentration about 5x10(19) cm(-3), and a simple one-band fit of the temperature-dependent mobility curve yields an acceptor concentration of about 9x10(19) cm(-3). This is strong evidence that the p-type dopant involves As, although it is not clear whether the acceptor is simply As-O or the recently suggested As-Zn-2V(Zn). (C) 2004 American Institute of Physics.