Strongly p-type ZnO is produced by the following sequence of steps: (1) evaporation of Zn3As2 on a fused-quartz substrate at 350 °C; and (2) sputtering of ZnO with substrate held at 450 °C. The electrical characteristics include: resistivity of 0.4 Ω cm, a mobility of 4 cm2∕V s, and a hole concentration of about 4×1018 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 5×1019 cm−3, and a simple one-band fit of the temperature-dependent mobility curve yields an acceptor concentration of about 9×1019 cm−3. This is strong evidence that the p-type dopant involves As, although it is not clear whether the acceptor is simply AsO or the recently suggested AsZn−2VZn.
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Copyright © 2004, American Institute of Physics. This article may be downloaded for personal use only. Any other use requires prior permission of the author and the American Institute of Physics. The following article appeared in Applied Physics Letters 85.22, and may be found at http://apl.aip.org/resource/1/applab/v85/i22/p5269_s1