Homogeneous 2D MoTe₂ p–n Junctions and CMOS Inverters formed by Atomic-Layer-Deposition-Induced Doping

Recently, α-MoTe₂, a 2D transition-metal dichalcogenide (TMD), has shown outstanding properties, aiming at future electronic devices. Such TMD structures without surface dangling bonds make the 2D α-MoTe₂ a more favorable candidate than conventional 3D Si on the scale of a few nanometers. The bandgap of thin α-MoTe₂ appears close to that of Si and is quite smaller than those of other typical TMD semiconductors. Even though there have been a few attempts to control the charge-carrier polarity of MoTe₂, functional devices such as p–n junction or complementary metal–oxide–semiconductor (CMOS) inverters have not been reported. Here, we demonstrate a 2D CMOS inverter and p–n junction diode in a single α-MoTe₂ nanosheet by a straightforward selective doping technique. In a single α-MoTe₂ flake, an initially p-doped channel is selectively converted to an n-doped region with high electron mobility of 18 cm² V⁻¹ s⁻¹ by atomic-layer-deposition-induced H-doping. The ultrathin CMOS inverter exhibits a high DC voltage gain of 29, an AC gain of 18 at 1 kHz, and a low static power consumption of a few nanowatts. The results show a great potential of α-MoTe₂ for future electronic devices based on 2D semiconducting materials.