Conversion of Charge Carrier Polarity in MoTe₂ Field Effect Transistor via Laser Doping

Abstract

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 (MoTe2) 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 MoTe2 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 MoTe2-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 cm2V−1s−1 in an intrinsic n-type channel and hole mobility of about 0.61 cm2V−1s−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 MoTe2-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 MoTe2 FET. This fabrication process of selective laser doping can potentially be used for larger-scale MoTe2 CMOS circuit applications.

Keywords

• 2D material
• laser doping
• CMOS inverter
• FET
• MoTe₂