The controllability of carrier density and major carrier type of transition metal dichalcogenides(TMDCs) is critical for electronic and optoelectronic device applications. To utilize doping in TMDC devices, it is important to understand the role of dopants in charge transport properties of TMDCs. Here, the effects of molecular doping on the charge transport properties of tungsten diselenide (WSe2) are investigated using three p-type molecular dopants, 2,3,5,6-tetrafluoro-7,7,8,8-tetracyanoquinodimethane (F4-TCNQ), tris(4-bromophenyl)ammoniumyl hexachloroantimonate (magic blue), and molybdenum tris(1,2-bis(trifluoromethyl)ethane-1,2-dithiolene) (Mo(tfd-COCF3)3). The temperature-dependent transport measurements show that the dopant counterions on WSe2 surface can induce Coulomb scattering in WSe2 channel and the degree of scattering is significantly dependent on the dopant. Furthermore, the quantitative analysis revealed that the amount of charge transfer between WSe2 and dopants is related to not only doping density, but also the contribution of each dopant ion toward Coulomb scattering. The first-principles density functional theory calculations show that the amount of charge transfer is mainly determined by intrinsic properties of the dopant molecules such as relative frontier orbital positions and their spin configurations. The authors’ systematic investigation of the charge transport of doped TMDCs will be directly relevant for pursuing molecular routes for efficient and controllable doping in TMDC nanoelectronic devices.
|Publication status||Published - 2021 Nov 2|
Bibliographical noteFunding Information:
J.‐K.K. and K.C. contributed equally to this work. The authors appreciate the financial support of the National Research Foundation of Korea (NRF) grant (Nos. 2021R1A2C3004783 and NRF‐2021R1C1C1010266) and the Nano Material Technology Development Program grant (No. 2021M3H4A1A02049651) through NRF funded by the Ministry of Science and ICT (MSIT) of Korea. K.C. appreciates the financail support of the NRF grant funded by the Korea government (MSIT) (No. 2021R1C1C2091728). J.‐H.L.'s work was supported by the KIST Institutional Program (Project No. 2E31201). Computational resources provided by KISTI Supercomputing Centre (Project No. KSC‐2020‐CRE‐0189) are gratefully acknowledged.
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All Science Journal Classification (ASJC) codes
- Materials Science(all)
- Mechanics of Materials
- Mechanical Engineering