Performance tunability of field-effect transistors using MoSSealloys.

Ultra-thin channel materials with excellent tunability of their electronic properties are necessary for the scaling of electronic devices. Two-dimensional materials such as transition metal dichalcogenides (TMDs) are ideal candidates for this due to their layered nature and great electrostatic control. Ternary alloys of these TMDs show composition-dependent electronic structure, promising excellent tunability of their properties. Here, we systematically compare molybdenum sulphoselenide (MoSSe) alloys, MoSSeand MoSSe. We observe variations in strain and carrier concentration with their composition. Using them, we demonstrate n-channel field-effect transistors (FETs) with SiOand high-HfOas gate dielectrics, and show tunability in threshold voltage, subthreshold slope (SS), drain current, and mobility. MoSSeshows better promise for low-power FETs with a minimum SS of 70 mV dec, whereas MoSSe, with its higher mobility, is suitable for faster operations. Using HfOas gate dielectric, there is an order of magnitude reduction in interface traps and 2× improvement in mobility and drain current, compared to SiO. In contrast to MoS, the FETs on HfOalso display enhancement-mode operation, making them better suited for CMOS applications.