Experimental and theoretical investigation of the effect of Sn on κ-Ga₂O₃ growth

In this work, the effect of Sn doping on the formation of an orthorhombic κ-Ga₂O₃ was investigated through experiments and first-principles calculations. The κ-Ga₂O₃ films were grown on sapphire and GaN on-sapphire by a mist chemical vapor deposition. For κ-Ga₂O₃ on sapphire grown at 650 °C, the β-phase emerged upon the strain relaxation of the κ-phase. Doping with Sn resulted in the thicker κ-phase with the thinner β-phase, suggesting the Sn-induced delay of strain relaxation. The phase stabilization can be attributed to the compressive strain induced by Sn substituting smaller Ga. This compressive strain also led to the thinner intermediate layers underneath the κ-phase. κ-Ga₂O₃ on GaN grown at 670 °C, on the other hand, exhibited neither the intermediate layers nor the β-phase layer on top. In comparison with the undoped κ-Ga₂O₃ on GaN, the Sn-doped sample showed a more abrupt interface with less severe rotational-domain formation. Our first-principles calculations based on density functional theory suggested that Sn⁺ on a pentahedral Ga site has the lowest formation energy under the oxygen-rich condition and maintains relatively low formation energy even under the oxygen-poor condition. Given the pentahedron coordination is unique to the κ-phase, this could have also contributed to the phase stabilization. Understanding the effect of Sn could provide ways to improve the structural quality of κ-Ga₂O₃, which is a promising material for next-generation electronics.Please check and confirm the edit made in article title.ConfirmedPlease confirm if the author names are presented accurately and in the correct sequence (given name, middle name/initial, family name). Author 1 Given name: [Ha Young] Last name [Kang] Author 4 Given name: [Tae Hoon] Last name [Lee], Author 1 Given name: [Roy Byung Kyu] Last name [Chung]. Also, kindly confirm the details in the metadata are correct.ConfirmedPlease confirm if the author names are presented accurately and in the correct sequence (given name, middle name/initial, family name). Author 1 Given name: [specify authors given name] Last name [specify authors last name]. Also, kindly confirm the details in the metadata are correct.Confirmed