Lennard-Jones Centre for Computational Materials Science

Charge accumulation and barrier formation at grain boundaries in ZnO decorated with bismuth

Domingos, HS and Carlsson, JM and Bristowe, PD and Hellsing, B (2002) Charge accumulation and barrier formation at grain boundaries in ZnO decorated with bismuth. In: UNSPECIFIED.

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Density functional plane-wave pseudopotential calculations have been performed on two high-angle grain boundaries in ZnO which have been decorated with various quantities of Bi. The results show that both grain boundaries, which have significantly different structures, can accommodate up to about 30% of substitutional Bi in qual tative agreement with experimental observations. The segregation of Bi to the boundaries results in local charge accumulation which is localized within Bi-Bi bonds or on Bi atoms. The charge accumulation in both boundaries results in fluctuations in potential across the interface and the formation of a barrier to electron transport. However, there is no evidence for a deep acceptor level usually associated with the Schottky barrier model. The present results suggest an alternative mechanism in which electrons are trapped in Bi-Bi bonds and depleted in an external field. However, defect states have not been ruled out and t is suggested that if they exist they are caused by more complex defects than those considered here.

Item Type: Conference or Workshop Item (UNSPECIFIED)
Uncontrolled Keywords: electronic-structure tilt boundary
Depositing User: Unnamed user with email sms67@eng.cam.ac.uk
Date Deposited: 05 Mar 2014 14:41
Last Modified: 17 Jun 2021 15:40

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