Journal ArticleGrowth of tetragonal PtO by molecular-beam epitaxy and its integration into β-Ga2O3 Schottky diodesHensling, Felix_V E (ORCID:0000000338527214); Parzyck, Christopher T (ORCID:0000000238357115); Cromer, Bennett (ORCID:0000000164927401); Al_Mamun, Md Abdullah (ORCID:0000000288616103); Suyolcu, Y Eren (ORCID:0000000309885194); Kalaydjian, L (ORCID:0009000808440402); Subedi, Indra (ORCID:0000000323006010); Park, Jisung (ORCID:0000000263057560); Azizie, Kathy (ORCID:0000000340214399); Song, Qi (ORCID:0000000212544131); van_Aken, Peter A (ORCID:0000000318901256); Podraza, Nikolas J (ORCID:000000023155559X); Cho, Kyeongjae (ORCID:0000000326987774); Jena, Debdeep (ORCID:0000000240764625); Xing, Huili G (ORCID:0000000227093839); Shen, Kyle M (ORCID:0000000169763434); Schlom, Darrell G (ORCID:0000000324936113); Vogt, Patrick (ORCID:0000000288008706)<p>We demonstrate the epitaxial growth of tetragonal platinum monoxide (PtO) on MgO, TiO2, and β-Ga2O3 single-crystalline substrates by ozone molecular-beam epitaxy. We provide synthesis routes and derive a growth diagram under which PtO films can be synthesized by physical vapor deposition. A combination of electrical transport and photoemission spectroscopy measurements, in conjunction with density functional theory calculations, reveal PtO to be a degenerately doped p-type semiconductor with a bandgap of Eg ≈ 1.6 eV. Spectroscopic ellipsometry measurements are used to extract the complex dielectric function spectra, indicating a transition from free-carrier absorption to higher photon energy transitions at E ≈ 1.6 eV. Using tetragonal PtO as an anode contact, we fabricate prototype Schottky diodes on n-type Sn-doped β-Ga2O3 substrates and extract Schottky barrier heights of ϕB &gt; 2.2 eV.</p>AIP Publishing2025-11-0110671053APL Materials13112166-532Xhttps://doi.org/10.1063/5.02742292039380National Science Foundation