The Structure of the [ZnIn -Vp]Q defect complex in Zn doped InP

摘要

We study the structure of the ZnIn-Vp defect complex in Zn doped InP as a function of the charge Q on the complex, using plane wave ab initio DFT-LDA calculations. We find that for all charge states from at least +2 to -3 the Zn is in a DX like position, sp2 bonded to three P atoms, with an empty pz orbital directed across the vacancy towards the triangle of In atoms. Electrons added/removed go to/from localised orbitals centred upon the In triangle, which shortens the In-In distances as (bonding) electrons are added. The Zn-In distances also shorten for electrostatic reasons, so that the vacancy volume is reduced by adding electrons to the complex, as seen in recent experiments.