Taking into account the novel layered structure and unusual electronic properties of MoS2 and WS2 on the side the lack of dangling bonds between these two components and donor-acceptor linkage effects, growth of the MoS2/WS2 vertical heterojunction film on the amorphous SiO2/Si substrate have created high demand. In this study, we reported the continuous, scalable, and vertical MoS2/WS2 heterostructure film by using a sputtering without a transfer step. The WS2 film was continuously grown on MoS2 and eventually led to the formation of the MoS2/WS2 vertical heterojunction film. Dozens of FETs fabricated on MoS2/WS2 continuous heterojunction film were created on the same substrate in a single lithographic fabrication step, allowing them to be commercialized and not only used in research applications. RAMAN spectra proved the formation of the MoS2/WS2 heterostructure film. In XPS measurements, it was shown that a separate MoS2 and WS2 layer was grown instead of the alloy structure. The polarity behavior of the MoS2/WS2 heterostructure FET was found to be modulated with different drain voltages as p-type to ambipolar and finally n-type conductivity because of the transition of band structure and Schottky barrier heights at different drain voltages. Electron mobility (7.2 cm(2) V.s(-1)) and on/off ratio (10(4)-10(5)) exhibited by the MoS2/WS2 heterostructure FETs displayed a more improved electrical performance than that of individual WS2, MoS2 devices. It was observed that the mobility value of MoS2/WS2 FET was approximately 514 times greater than WS2 FET and 800 times greater than MoS2 FET. Additionally, the MoS2/WS2 FET on/off ratio was larger than 2 order MoS2 FET and 1 order WS2 FET. The film of continuous vertical heterojunctions as in the MoS2/WS2 currents in the study would be a promising candidate for nanoelectronics fields. This work demonstrated the progress towards realizing carrier-type controlled high-performance MoS2/WS2 heterojunction-based FETs for future logic devices.
展开▼
