Zhou Zuoping, Lin Jun-Fa, Zeng Zimeng, Ma Xiaoping, Liang Liang, Li Yuheng, Zhao Zhongyuan, Mei Zhen, Yang Huaixin, Li Qunqing, Wu Jian, Fan Shoushan, Chen Xi, Xia Tian-Long, Wei Yang
Department of Physics, Tsinghua University, Beijing 100084, China.
Tsinghua-Foxconn Nanotechnology Research Center, Tsinghua University, Beijing 100084, China.
Nano Lett. 2024 Apr 17;24(15):4408-4414. doi: 10.1021/acs.nanolett.4c00056. Epub 2024 Apr 3.
Tuning the interfacial Schottky barrier with van der Waals (vdW) contacts is an important solution for two-dimensional (2D) electronics. Here we report that the interlayer dipoles of 2D vdW superlattices (vdWSLs) can be used to engineer vdW contacts to 2D semiconductors. A bipolar WSe with BaTaS (BTS) vdW contact was employed to exhibit this strategy. Strong interlayer dipoles can be formed due to charge transfer between the BaTaS and TaS layers. Mechanical exfoliation breaks the superlattice and produces two distinguished surfaces with TaS and BaTaS terminations. The surfaces thus have opposite surface dipoles and consequently different work functions. Therefore, all the devices fall into two categories in accordance with the rectifying direction, which were verified by electrical measurements and scanning photocurrent microscopy. The growing vdWSL family along with the addition surface dipoles enables prospective vdW contact designs and have practical application in nanoelectronics and nano optoelectronics.
通过范德华（vdW）接触来调节界面肖特基势垒是二维（2D）电子学的一个重要解决方案。在此，我们报道二维vdW超晶格（vdWSLs）的层间偶极子可用于设计与二维半导体的vdW接触。采用具有BaTaS（BTS）vdW接触的双极WSe来展示这一策略。由于BaTaS层和TaS层之间的电荷转移，可形成强层间偶极子。机械剥离会破坏超晶格，并产生具有TaS和BaTaS终端的两个不同表面。因此，这些表面具有相反的表面偶极子，从而具有不同的功函数。所以，所有器件根据整流方向可分为两类，这通过电学测量和扫描光电流显微镜得到了验证。不断发展的vdWSL家族以及额外的表面偶极子使得前瞻性的vdW接触设计成为可能，并在纳米电子学和纳米光电子学中有实际应用。
