Homogeneous platinum diselenide metal/semiconductor coplanar structure fabricated by selective thickness control

For the realization of two-dimensional material-based high-performance electronic devices, the formation of a stable, high-quality metal-semiconductor contact is a key factor. Platinum diselenide (PtSe₂), a group-10 transition metal dichalcogenide, is a promising candidate owing to its unique property of layer-dependent semiconductor-to-semimetal transition. Here, a scalable and controllable method utilizing an inductively coupled plasma treatment is reported for selectively controlling the thickness of PtSe₂ flakes. The PtSe₂ transforms from a semimetal to a semiconductor when the thickness decreases below 3 nm. A field-effect transistor is fabricated based on the homogeneous platinum diselenide metal/semiconductor coplanar structure (metallic PtSe₂ as source/drain electrodes and semiconductor PtSe₂ as a channel), which demonstrates a low contact resistance of 362 Ω μm and carrier mobility of 150 cm² V^-1 s^-1, outperforming the previously reported PtSe₂-based devices.