【International Papers】High-temperature annealing induced electrical compensation in UID and Sn doped β-Ga₂O₃ bulk samples: The role of VGa–Sn complexes

      Researchers from the Sorbonne Université have published a dissertation titled " High-temperature annealing induced electrical compensation in UID and Sn doped β-Ga₂O₃ bulk samples: The role of VGa–Sn complexes  " in Journal of Applied Physics.

Abstract

      By electron paramagnetic resonance (EPR) and photoluminescence spectroscopy, we have investigated the effect of high-temperature annealing under oxygen atmosphere on the electrical and defect properties of unintentionally doped (UID) and highly doped (Sn) n-type bulk samples of β-Ga₂O₃. The EPR analysis of the shallow donor concentration shows efficient electrical compensation in the Sn doped β-Ga₂O₃ samples but only marginal changes for the UID samples. In the Sn doped samples, we observe the formation of a Ga vacancy related acceptor defect responsible for the compensation. Its spin Hamiltonian parameters are electron spin S = 1/2, g-tensor g₁₁ = 2.0423, g₂₂ = 2.0160, g₃₃ = 2.0024, and hyperfine interaction (hf) with two equivalent Ga atoms with A(⁶⁹Ga) = 28 G. To identify its microscopic structure, we have performed first-principles calculations of the EPR parameters and the associated photoluminescence spectra of different Ga vacancy–Sn donor complexes, including a simple nearest neighbor pair V_Ga–Sn_Ga. From these calculations, we attribute this V_Ga defect to a negatively charged split vacancy complex V_Ga1–Sn_ib–V_Ga1. This V_Ga defect is different from the irradiation induced V_Ga center.