Defect analysis and engineering in ZnO

Zinc oxide has numerous applications in electronic and optoelectronic devices. Progress is currently hampered by a lack of control over electrical conductivity: ZnO is typically n-type conductive, the cause of which has been widely debated. A first-principles investigation, based on density functional theory, shows that native defects are unlikely to be the cause of the unintentional n-type conductivity. Detailed results for the oxygen vacancy show that it is a deep donor, and that its paramagnetic state is metastable. An investigation of likely donor impurities reveals that hydrogen acts as a shallow donor. Experimental results are discussed in the light of these new insights. r 2001 Elsevier Science B.V. All rights reserved.