Conversion of Charge Carrier Polarity in MoTe 2 Field Effect Transistor via Laser Doping.

A two-dimensional (2D) atomic crystalline transition metal dichalcogenides has shown immense features, aiming for future nanoelectronic devices comparable to conventional silicon (Si). 2D molybdenum ditelluride (MoTe ₂ ) has a small bandgap, appears close to that of Si, and is more favorable than other typical 2D semiconductors. In this study, we demonstrate laser-induced p-type doping in a selective region of n-type semiconducting MoTe ₂ field effect transistors (FET) with an advance in using the hexagonal boron nitride as passivation layer from protecting the structure phase change from laser doping. A single nanoflake MoTe ₂ -based FET, exhibiting initial n-type and converting to p-type in clear four-step doping, changing charge transport behavior in a selective surface region by laser doping. The device shows high electron mobility of about 23.4 cm ² V ^-1 s ^-1 in an intrinsic n-type channel and hole mobility of about 0.61 cm ² V ^-1 s ^-1 with a high on/off ratio. The device was measured in the range of temperature 77-300 K to observe the consistency of the MoTe ₂ -based FET in intrinsic and laser-dopped region. In addition, we measured the device as a complementary metal-oxide-semiconductor (CMOS) inverter by switching the charge-carrier polarity of the MoTe ₂ FET. This fabrication process of selective laser doping can potentially be used for larger-scale MoTe ₂ CMOS circuit applications.