A DFT study of defects in LiGaO2

Name: Klichchupong Dabsamut

LCSH: Kasetsart University -- Dissertations. Ph.D. (Physics) 2022

Classification :.LCCS: QC20.7.D43

LCSH: Kasetsart University. -- Department of Physics -- Dissertatiions

LCSH: Density functionals

LCSH: Semiconductors

Abstract: The intrinsic and extrinsic defects in LiGaO2 were studied using hybrid functional calculations. In case of intrinsic defects, we investigated vacancy defects (lithium (VLi), gallium (VGa), and oxygen (VO) vacancies) and antisite defects (Li on Ga-site (LiGa) and Ga on Li-site (GaLi)) in LiGaO2. The lowest energy intrinsic defect is found to be GaLi2+ donor. In which it is likely to be compensated by VLi1− and in part by LiGa 2− in the more Li-rich conditions. VGa has high formation energy under all reasonable conditions. Both GaLi and VO are found to be negative U centers with deep 2+/0 transition levels. For monoatomic extrinsic defects, we presented Si, Ge and Sn as n-type dopants while Zn on a cation site and N on O site as p-type dopants in LiGaO2. We found that, n-type cases, both SiGa and GeGa are found to be shallow donors, while SnGa is found to be a somehow deeper donor. In site preference studied, all three group-IV dopants are found to favor the Ga over the Li site when the Fermi level is in the upper part of the gap, corresponding to ntype doping and for Li-rich growth conditions. Therefore, the prospects for n-type doping are thus favorable. For p-type dopants, NO is found to be amphoteric with both deep donor and acceptor type transition levels. Zn has a significant site competition between ZnLi (donor) and ZnGa (acceptor) levels, which would pin the Fermi level in the middle of the gap. Thus, p-type doping cannot be achieved with these dopants. The molecular dopants including N2, NO and O2 are considered potential acceptors for p-type doping. Their optimal placement and orientation relative to the lattice is studied as well as their transition levels and energy of formation. Unfortunately, they are found to have deep acceptor level transition states. We discuss the relation of the transition levels to the one-electron levels, their spin state, and defect wave functions. They are found to be closely related to those of the corresponding vacancies.

Kasetsart University. Office of the University Library

Address: Bangkok

Email: tdckulib@ku.ac.th

Name: Adisak Boonchun

Role: Thesis Advisor

Name: Pakpoom Reunchan

Role: Thesis CO-Advisor

Name: Jiraroj T-Thienprasert

Role: Thesis CO-Advisor

Created: 2022

Modified: 2025-07-27

Issued: 2025-07-27

วิทยานิพนธ์/Thesis

application/pdf

URL: https://www.lib.ku.ac.th/KUthesis/2565/klichchupong-dab-all.pdf

CallNumber: QC20.7.D43 .K54

eng

DegreeName: Doctor of Philosophy

Level: Doctoral Degraee

Descipline: Physics

Grantor: Kasetsart University

©copyrights Kasetsart University

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