Tip-Mediated Bandgap Tuning for Monolayer Transition Metal Dichalcogenides
Tip-Mediated Bandgap Tuning for Monolayer Transition Metal Dichalcogenides
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DOI：
10.1021/acsnano.2c05841
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发表时间：
2022-08-29
期刊：
影响因子：
17.1
通讯作者：
Lin，Chun-Liang
中科院分区：
文献类型：
--
作者：
Lin，Meng-Kai;Chen，Guan-Hao;Lin，Chun-Liang
单层过渡金属二硫属化物为开发石墨烯以外的先进电子产品提供了合适的平台。类似于二维分子框架，这样的单层的电子性质可以是敏感的扰动，从周围的电子结构的隐含的可调性是极大的兴趣。使用扫描隧道显微镜/光谱，我们展示了带隙工程技术在两个单层材料，MoS 2和PtTe 2，隧道电流作为控制参数。随着隧穿电流的增加，单层MoS 2的带隙呈指数下降，表明存在电场诱导的带隙重整化效应.单层PtTe 2，相比之下，表现出更强的间隙减少，和可逆的载流子到金属的过渡发生在一个温和的隧穿电流。这种不寻常的单层PtTe 2的开关行为，没有看到散装半金属PtTe 2，可以归因于其表面的电子结构，可以很容易地耦合到隧道尖端，如理论计算所示。
Monolayer transition metal dichalcogenides offer an appropriate platform for developing advanced electronics beyond graphene. Similar to two-dimensional molecular frameworks, the electronic properties of such monolayers can be sensitive to perturbations from the surroundings; the implied tunability of electronic structure is of great interest. Using scanning tunneling microscopy/spectroscopy, we demonstrated a bandgap engineering technique in two monolayer materials, MoS2and PtTe2, with the tunneling current as a control parameter. The bandgap of monolayer MoS2decreases logarithmically by the increasing tunneling current, indicating an electric-field-induced gap renormalization effect. Monolayer PtTe2, by contrast, exhibits a much stronger gap reduction, and a reversible semiconductor-to-metal transition occurs at a moderate tunneling current. This unusual switching behavior of monolayer PtTe2, not seen in bulk semimetallic PtTe2, can be attributed to its surface electronic structure that can readily couple to the tunneling tip, as demonstrated by theoretical calculations.