[16a-C43-1~11] 7.1 X-ray technologies

10:00 AM - 10:15 AM JST(1:00 AM - 1:15 AM UTC)Presentation by Applicant for JSAP Young Scientists Presentation AwardEnglish Presentation

[16a-C43-5] Atomic site occupancy of the Si dopant in κ-Ga₂O₃(001) studied by photoelectron holography

〇(D)YUHUA TSAI^1,2, Yusuke Hashimoto³, Piero Mazzolini^4,5, Parisini Antonella⁴, Bosi Matteo⁵, Seravalli Luca⁵, Tomohiro Matsushita³, Yoshiyuki Yamashita^1,2 (1.NIMS, 2.Kyushu Univ., 3.NAIST, 4.UNIPR, 5.IMEM-CNR)

Keywords:

Ga2O3,Photoelectron spectroscopy (PES),Photoelectron holography (PEH)

For Ga₂O₃, there are six crystal polymorphs of Ga₂O₃: α-, β-, δ-, γ-, ε-, and κ-Ga₂O₃. Among them, β-Ga₂O₃ has received the most attention due to its highest thermal stability. Recently, the orthorhombic κ-Ga₂O₃ has gained attention due to its large spontaneous polarization and its ferroelectricity. For κ-Ga₂O₃, Si is used as the dopant to control the electrical properties. There are three inequivalent Ga atomic sites in κ-Ga₂O₃; octahedral (Octa), pentahedral (Penta), and tetrahedral (Tetra). Therefore, in order to control the electrical properties, the atomic structure of active dopant site in Si-doped κ-Ga₂O₃ should be clarified. In the present study, we investigated atomic positions and the chemical states of the Si dopants for Si-doped κ-Ga₂O₃ using photoelectron spectroscopy (PES) and photoelectron holography (PEH).
The Si-doped κ-Ga₂O₃ epitaxial layers were grown on a c-plane sapphire substrates prepared by the MOVPE method. The PEH measurements were performed at the BL25SU beamline of SPring-8.
By comparing the experimental and the simulated PEHs, the Si dopant site is attributed to the mixture of the Octa, Penta, and Tetra Si_Ga sites. The ratios for the Tetra, Penta, and Octa Si_Ga sites are estimated to be 51.0%, 35.2%, and 13.8%, respectively. The more detailed discussions will be performed in our presentation.