Density-functional study of the structure and stability of ZnO surfaces

Abstract

An extensive theoretical investigation of the nonpolar (1010) and (1120) surfaces as well as the polar zinc terminated (0001)-Zn and oxygen terminated (0001)-O surfaces of ZnO is presented. Particular attention is given to the convergence properties of various parameters such as basis set, k-point mesh, slab thickness, or relaxation constraints within LDA and PBE pseudopotential calculations using both plane wave and mixed basis sets. The pros and cons of different approaches to deal with the stability problem of the polar surfaces are discussed. Reliable results for the structural relaxations and the energetics of these surfaces are presented and compared to previous theoretical and experimental data, which are also concisely reviewed and commented.

Silica Surface Features and Their Role in the Adsorption of Biomolecules: Computational Modeling and Experiments

“…For oxides, extra care should be exerted in order to avoid either charged slabs or slabs with a large dipole moment across the slab itself, as in this case they are electronically unstable. 292,293 For a covalent material like silica, bond cutting brings about the formation of a variety of surface defects, the most relevant being: the Q 3 (•) silyl Si• , the Q 3 (O•) siloxy E' SiO•, the Q 2 (:) >Si: and the Q 2 (O) silanone >Si=O. The nature and stability of these defects has been discussed in the literature [69][70][71][294][295][296][297][298][299][300][301][302][303][304][305] showing that all of them, without exception, are thermodynamically unstable with respect to water hydroxylation.…”

The Review of Semiconductor Gas Sensor for Nox Detcting

“…An electron-depleted space charge layer is created on the ZnO nanoparticles' surface by the adsorption of molecular and atomic oxygen which is a remarkable characteristic of receptor function. This adsorbed oxygen also can determines the surface potential barrier height, surface charge layer thickness, surface charge and Debye length (Kunat, Becker, Burghaus, & Wöll, 2002;Meyer & Marx, 2003;Valtiner et al, 2010). The gas response and selectivity of ZnO gas sensors are influenced by these parameters.…”

Comparative study on the properties of ZnO nanowires and nanocrystalline thin films

“…It has been shown [40,41,42,43,44] that ZnO films and NWs have surface defects, such as electron vacancies, oxygen vacancies, and interstitial Zn atoms in the surface lattice. These defects can interact with H + ions and hydroxyls OH -dissociated from the H 2 O molecules through the following reactions:…”

“…According to these models [41,42,43,44], we can assume that the first step of adsorption in the material will be chemisorption, while the next step will be physisorption of water molecules on top of the chemisorbed layer, as shown in Fig. 5.…”