2D semiconductors are poised to revolutionize the future of electronics and photonics, much like transparent oxide conductors and semiconductors have revolutionized the display industry. Herein, these two types of materials are combined to realize fully transparent 2D electronic devices and circuits. Specifically, a large-area chemical vapor deposition process is developed to grow monolayer MoS2 continuous films, which are, for the first time, combined with transparent conducting oxide (TCO) contacts. Transparent conducting aluminum doped zinc oxide contacts are deposited by atomic layer deposition, with composition tuning to achieve optimal conductivity and band-offsets with MoS2. The optimized process gives fully transparent TCO/MoS2 2D electronics with average visible-range transmittance of 85%. The transistors show high mobility (4.2 cm2 V−1 s−1), fast switching speed (0.114 V dec−1), very low threshold voltage (0.69 V), and large switching ratio (4 × 108). To our knowledge, these are the lowest threshold voltage and subthreshold swing values reported for monolayer chemical vapor deposition MoS2 transistors. The transparent inverters show fast switching properties with a gain of 155 at a supply voltage of 10 V. The results demonstrate that transparent conducting oxides can be used as contact materials for 2D semiconductors, which opens new possibilities in 2D electronic and photonic applications.
Bibliographical noteKAUST Repository Item: Exported on 2020-10-01
Acknowledgements: Z.D. and Z.W. contributed equally to this work. Z.D., Z.W., X.-X.Z., and H.N.A. designed the work. Z.D. and Z.W. performed the CVD growth of MoS2. Z.D. and Z.W. performed the transfer and material characterization of MoS2. X.H. performed the e-beam lithography. Z.W. performed the ALD AZO and HfO2 deposition. Z.W. performed the design, fabrication, and characterization of the transparent circuit. Z.D., Z.W., X.H., X.-X.Z., and H.N.A. composed and thoroughly discussed this report. All authors contributed to the technical parts developed in this report. Research reported in this publication was supported by King Abdullah University of Science and Technology (KAUST).