Microscopic origin of inhomogeneous transport in four-terminal tellurene devices
Microscopic origin of inhomogeneous transport in four-terminal tellurene devices
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DOI：
10.1063/5.0025955
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发表时间：
2020-12
影响因子：
4
通讯作者：
Benjamin M. Kupp;G. Qiu;Yixiu Wang;C. Casper;T. Wallis;J. Atkin;Wenzhuo Wu;P. Ye;P. Kabos;S. Berweger
中科院分区：
文献类型：
--
作者：
Benjamin M. Kupp;G. Qiu;Yixiu Wang;C. Casper;T. Wallis;J. Atkin;Wenzhuo Wu;P. Ye;P. Kabos;S. Berweger
碲-元素碲的2D形式-提供了一个有吸引力的替代传统的2D半导体，由于其高双极迁移率，容易的溶液处理，和掺杂剂嵌入到其1D货车德瓦尔斯晶格的可能性。在这里，我们研究的微观起源的运输各向异性光刻定义的四端碲设备使用空间分辨近场扫描微波显微镜（SMM）。我们的电导率和载流子类型敏感的SMM成像显示，相邻和相对的终端之间测量的整体p型传输源于设备边缘的强p型字符。尽管使用原子层沉积生长的保形外涂层，n掺杂的设备内部，我们只观察到弱的n型运输沿着在正背栅电压的主要器件沟道。这种弱的n-型传输沿着器件沟道被示出产生于电极的几微米内的局部p-掺杂，其产生从n-型内部到电极的传输势垒。这些结果揭示了如何利用背栅相关的导电各向异性来权衡非冯诺依曼架构的不同输入。
Tellurene—the 2D form of elemental tellurium—provides an attractive alternative to conventional 2D semiconductors due to its high bipolar mobilities, facile solution processing, and the possibility of dopant intercalation into its 1D van der Waals lattice. Here, we study the microscopic origin of transport anisotropy in lithographically defined four-terminal tellurene devices using spatially resolved near-field scanning microwave microscopy (SMM). Our conductivity- and carrier type-sensitive SMM imaging reveals that the overall p-type transport measured between adjacent and opposite terminals originates from strong p-type character at the device edges. Despite using an atomic layer deposition-grown conformal overcoat that n-dopes the device interior, we observe only weak n-type transport along the main device channel at positive backgate voltages. This weak n-type transport along the device channel is shown to arise from local p-doping within a few micrometers of the electrodes, which produces a transport barrier from the n-type interior to the electrodes. These results reveal how the backgate-dependent conduction anisotropy could be leveraged to weigh different inputs for non-von Neumann architectures.