Shafi Abde Mayeen, Uddin Md Gius, Cui Xiaoqi, Ali Fida, Ahmed Faisal, Radwan Mohamed, Das Susobhan, Mehmood Naveed, Sun Zhipei, Lipsanen Harri
Department of Electronics and Nanoengineering, Aalto University, Tietotie 3, FI-02150, Finland.
QTF Centre of Excellence, Department of Applied Physics, Aalto University, Aalto, FI-00076, Finland.
Adv Sci (Weinh). 2023 Oct;10(29):e2303437. doi: 10.1002/advs.202303437. Epub 2023 Aug 8.
Molybdenum ditelluride (MoTe ) exhibits immense potential in post-silicon electronics due to its bandgap comparable to silicon. Unlike other 2D materials, MoTe allows easy phase modulation and efficient carrier type control in electrical transport. However, its unstable nature and low-carrier mobility limit practical implementation in devices. Here, a deterministic method is proposed to improve the performance of MoTe devices by inducing local tensile strain through substrate engineering and encapsulation processes. The approach involves creating hole arrays in the substrate and using atomic layer deposition grown Al O as an additional back-gate dielectric layer on SiO . The MoTe channel is passivated with a thick layer of Al O post-fabrication. This structure significantly improves hole and electron mobilities in MoTe field-effect transistors (FETs), approaching theoretical limits. Hole mobility up to 130 cm V s and electron mobility up to 160 cm V s are achieved. Introducing local tensile strain through the hole array enhances electron mobility by up to 6 times compared to the unstrained devices. Remarkably, the devices exhibit metal-insulator transition in MoTe FETs, with a well-defined critical point. This study presents a novel technique to enhance carrier mobility in MoTe FETs, offering promising prospects for improving 2D material performance in electronic applications.
二碲化钼（MoTe₂）因其与硅相当的带隙，在硅基后电子学领域展现出巨大潜力。与其他二维材料不同，MoTe₂在电输运中易于进行相位调制且能有效控制载流子类型。然而，其不稳定的性质和低载流子迁移率限制了其在器件中的实际应用。在此，提出一种确定性方法，通过衬底工程和封装工艺引入局部拉伸应变来提高MoTe₂器件的性能。该方法包括在衬底中创建孔阵列，并在SiO₂上使用原子层沉积生长的Al₂O₃作为额外的背栅介电层。MoTe₂沟道在制造后用厚层Al₂O₃进行钝化。这种结构显著提高了MoTe₂场效应晶体管（FET）中的空穴和电子迁移率，接近理论极限。实现了高达130 cm² V⁻¹ s⁻¹的空穴迁移率和高达160 cm² V⁻¹ s⁻¹的电子迁移率。与未受应变的器件相比，通过孔阵列引入局部拉伸应变可使电子迁移率提高多达6倍。值得注意的是，这些器件在MoTe₂ FET中表现出金属 - 绝缘体转变，具有明确的临界点。本研究提出了一种增强MoTe₂ FET中载流子迁移率的新技术，为改善二维材料在电子应用中的性能提供了广阔前景。
