Demonstration of the donor characteristics of Si and O defects in GaN using hybrid QM/MM

DOI: 10.1002/pssa.201600445

Authors: Zijuan Xie (Harbin Institute of Technology; University College London) , Yu Sui (Harbin Institute of Technology) , John Buckeridge (University College London) , C. Richard A. Catlow (University College London) , Thomas W. Keal (STFC) , Paul Sherwood (STFC) , Aron Walsh (University of Bath) , David O. Scanlon (University College London; Diamond Light Source) , Scott M. Woodley (University College London) , Alexey A. Sokol (University College London)
Co-authored by industrial partner: No

Type: Journal Paper
Journal: Physica Status Solidi (a)

State: Published (Approved)
Published: November 2016

Abstract: Using hybrid quantum mechanical/molecular mechanical (QM/MM) embedded cluster calculations, we investigate the stabilization of silicon and oxygen dopants in GaN. Formation energies of Si on a Ga site and O on an N site are calculated at two levels of theory using conventional thermochemical and kinetic exchange and correlation density functionals (B97-2 and BB1k). We confirm the shallow donor nature of these substitutional defects. We find that the 0/1+ transition levels for both Si and O species lie well above the bottom of the conduction band, in agreement with previous supercell-based simulations. The origin of this artifact is discussed in the context of relevant experimental results and we show how correct in-gap shallow levels can be ascertained in good agreement with experiment.

Journal Keywords: cluster calculations; doping; GaN; n-type semiconductors; oxygen; silicon

Subject Areas: Materials, Chemistry, Physics


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