High carrier mobility in single-crystal PtSe ₂ grown by molecular beam epitaxy on ZnO(0001)

Abstract PtSe ₂ is attracting considerable attention as a high mobility two-dimensional material with envisioned applications in microelectronics, photodetection and spintronics. The growth of high quality PtSe ₂ on insulating substrates with wafer-scale uniformity is a prerequisite for electronic transport investigations and practical use in devices. Here, we report the growth of highly oriented few-layers PtSe ₂ on ZnO(0001) by molecular beam epitaxy. The crystalline structure of the films is characterized with electron and x-ray diffraction, atomic force microscopy and transmission electron microscopy. The comparison with PtSe ₂ layers grown on graphene, sapphire, mica, SiO ₂ and Pt(111) shows that among insulating substrates, ZnO(0001) yields films of superior structural quality. Hall measurements performed on epitaxial ZnO/PtSe ₂ with five monolayers of PtSe ₂ show a clear semiconducting behaviour and a high mobility in excess of 200 cm ² V ⁻¹ s ⁻¹ at room temperature and up to 447 cm ² V ⁻¹ s ⁻¹ at low temperature.