期刊
ACS APPLIED MATERIALS & INTERFACES
卷 14, 期 27, 页码 31121-31130出版社
AMER CHEMICAL SOC
DOI: 10.1021/acsami.2c06968
关键词
epitaxial growth; WS2; NiTe2; vdW heterostructures; photodetector
资金
- National Natural Science Foundation of China [51772088, 51872198, 52172151]
- Natural Science Foundation of Hunan Province [2022JJ30172]
- Natural Science Foundation of Tianjin [18JCYBJC42500]
This study demonstrates the fabrication of p-type WS2 field-effect transistors and enhanced optoelectronic performance using NiTe2/WS2 heterostructures formed by van der Waals epitaxy.
Two-dimensional (2D) transition metal dichalcogenides (TMDCs) have great potential applications in the electronic and optoelectronic devices. Nevertheless, due to the difficulty in the efficient doping of atomic-thickness TMDCs or Fermi level pinning (FLP) effects at the metal/semiconductor interface, most TMDC devices exhibit the n-type conduction polarity, which significantly limits their functional applications based on the p-n junction. Here, 2D semi-metal NiTe2 nanosheets were epitaxially grown on the WS2 monolayer by a two-step chemical vapor deposition route. The microstructure and optical characterizations confirm that the vertically stacked NiTe2/WS2 heterostructures are formed by van der Waals epitaxy. Interestingly, p-type WS2 field-effect transistors can be obtained with the hole mobility of similar to 4.22 cm(2)/Vmiddots, when the epitaxial NiTe2 sheets act as the source/drain electrodes. This is attributed to the decreased FLP effect and hence the low potential barrier for holes at the van der Waals contacts. Furthermore, the photodetectors based on the heterostructures show a 2 orders of magnitude increase in the switch ratio, responsivity, and detectivity and a 1 order of magnitude increase in the rise and decay speeds relative to those based on pristine WS2. This work paves the way to realize the p-type contact for monolayer WS2 with significantly enhanced optoelectronic performance.
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