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