摘要
Small contact resistance and low Schottky barrier height(SBH)are the keys to energy-efficient electronics and optoelectronics.Two-dimensional(2D)semiconductors-based field effect transistors(FETs),holding great promise for next-generation information circuits,still suffer from poor contact quality at the metal–semiconductor junction interface,which severely hinders their further applications.Here,a novel contact strategy is proposed,where Bi_(2)Te_(3)nanosheets with high conductivity were in-situ epitaxially grown on MoS_(2)as van der Waals contacts,which can effectively avoid the damage to MoS_(2)caused during the device manufacturing process,leading to a high-performance MoS_(2)FET.Moreover,the small work function difference between Bi_(2)Te_(3)and MoS_(2)(Bi_(2)Te_(3):4.31 eV,MoS_(2):4.37 eV,measured by Kelvin probe force microscopy(KPFM)),enables small band bending and Ohmic contact at the junction interface.Electrical characterizations indicate that the MoS_(2)FET device with Bi_(2)Te_(3)contacts possesses a high current on/off ratio(5×107),large effective carrier mobility(90 cm^(2)/(V·s)),and low flat-band SBH(60 meV),which is favorable as compared with MoS_(2)FET with traditional Cr/Au electrodes contacts,and superior to the vast majority of the reported chemical vapor deposition(CVD)MoS_(2)-based FET device.The demonstration of epitaxial van der Waals Bi_(2)Te_(3)contacts will facilitate the application of 2D MoS_(2)nanosheet in next-generation low-power consumption electronics and optoelectronics.
基金
The authors are grateful to the National Key R&D Program of China(No.2022YFA1402501)
the National Natural Science Foundation of China(Nos.51902098,62090035,U22A2013,and U19A2090)
the Key Program of Science and Technology Department of Hunan Province(Nos.2019XK2001 and 2020XK2001)
the Science and Technology Innovation Program of Hunan Province(Nos.2021RC3061,2020RC2028,and 2021RC2042)
the Natural Science Foundation of Hunan Province(No.2021JJ20016)
the Project funded by China Postdoctoral Science Foundation(Nos.2020M680112 and 2021M690953).