Improved characteristics of MoS₂ transistors with selective doping using 1,2-dichloroethane

We demonstrate area-selective doping of MoS2 field-effect transistors using 1,2-dichloroethane (DCE) solution. In the device manufacturing process, area-selective chemical doping was used to implement contact engineering in the source/drain region. X-ray photoelectron spectroscopy (XPS) and Raman spectroscopy measurements were performed to confirm the blocked layer (BL) using a photoresist, which suppressed the doping effect of the DCE treatment. In the XPS results, the main core level of the MoS2 flake with BL did not shift, whereas that of the MoS2 flake without BL changed by approximately 0.24 eV. In the case of the MoS2 flakes with a BL, the vibrational modes of the Raman scattering did not shift. Conversely, the two Raman peaks of the MoS2 flake without BL red-shifted because of increasing electron-phonon scattering. The effect of area-selective doping was confirmed by electrical measurements. The field-effect mobility and the subthreshold swing were enhanced from 4.07 to 31.5 cm(2) (V s)(-1) and from 1.26 to 0.401 V/decade, respectively.