Polarity-Reversible 2D MoTe₂ Field-Effect Transistors and Their Logic Applications

2H-type molybdenum ditelluride (MoTe₂) has been greatly spotlighted as a semiconducting TMDC material which facilitates polarity transition between high performance n- and p-type characteristics due to its small bandgap of ~ 1.0 eV. However, the reversible polarity control between unipolar n- and p-type conductions in MoTe₂ is still challenging, which causes difficulties for device strategies which require unlimited manipulation of carrier transport properties of MoTe₂ devices. Here, we demonstrate reversible polarity transition between unipolar n- and p-type characteristics in MoTe₂ FETs by controlling annealing environment. Fermi level shift and formation/removal of oxygen relevant phases in the MoTe₂ layer are repetitively occurred with the change of annealing atmospheres. Also, the polarity modulations in well-designed MoTe₂ devices are compatible with the phenomena presented in MoTe₂ material. This precise polarity control in MoTe₂ FETs eventually permits to realize functional logic application such as an inverter circuit.