Bulk, interface and surface properties of zinc oxide

Abstract

Zinc oxide (ZnO) is a highly developed oxide semiconductor that has been widely employed in industry as varistor ceramics, transparent conductor films, surface acoustic wave resonators, and so on. However, many questions about its fundamental properties remain unanswered. For instance, density functional theory simulations are currently contradicting the common conception established by many experimental scientists that non-stoichiometry is the primary factor inducing the native conductivity of ZnO. Thus, it may be necessary to reconstruct the conceptual models of the solid-state chemistry and physics of oxide semiconductors. In this context, this paper gathers the knowledge and suggestions presented in previous studies and attempts to find directions for the next steps in further scientific and technological development of ZnO-related materials and structures.

Electronic Transport Properties Governed by Polarity Control through Tailoring of ZnO Bilayer Structures

“…Surface terminations can be defined as either polar Zn-terminated-surface (Zn-surface) or oxygen-terminated-surface (O-surface) and can have an effect on film growth and final film properties. Previous studies have been devoted to understanding the relationship between polarity and the presence of impurities, defect incorporation, and orientation of the crystalline facet. − For example, the impurity incorporation behavior in homoepitaxial ZnO films depends on the orientation of growth facet. , In addition, it has been reported that impurities, which can be regarded as potential donors, can be easily incorporated into the ZnO lattice on the O-surface . However, impurities, which are the cause of acceptor states in ZnO, are incorporated on the Zn-surface .…”

Spatially-resolved cathodoluminescence spectroscopy of ZnO defects

“…There is now a considerable body of CLS research on ZnO, motivated by its potential for optoelectronic and microelectronic applications 69 and based on a number of factors: its 60 meV exciton binding energy for efficient light emitters, high mobility transport, 70 ease of large area growth, 71 wet chemical processing, resistance to space radiation, and environmental compatibility. For a general review of ZnO materials and devices, see Özgür et al 72 Extended to the nanoscale, CLS can describe how ZnO properties vary within interfaces, micro-and nanostructures together with how they can depend on growth and processing.…”