Authors: Changjie Zhou Junyong Kang
Publish Date: 2008/01/19
Volume: 19, Issue: 1, Pages: 229-233
Abstract
We investigated the electronic structures of ZnO0001Zn and 000−1O surfaces by means of firstprinciples calculations According to the results of the relaxation and the electrostatic criterion the surface geometric relaxations and the charge transfer almost take place on the outer four double layers For the 0001Zn surface steep surface states appear in the band gap of bulk ZnO and follow the bottom of bulk conduction band Moreover Fermi level shifts up into the conduction band which leads to the ntype conduction behaviour of 0001Zn surface The dispersed partial charge densities derived from the Zn4s state spread evenly on the surface and apparently lead to difficulty of getting an atomresolved STM image For the 000−1O surface flat surface states emerge above the top of the valence band of bulk ZnO as Fermi level shifts down a little into the valence band Based on that the 000−1O surface can be predicted to have the ptype conductivity The localized partial charge densities derived from the O2p state makes it possible to get an atomresolved STM image within the low bias voltage
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