Samsung-SKKU Graphene/2D Center (SSGC), Department of Nano Science and Technology, SKKU Advanced Institute of Nano-Technology (SAINT), Sungkyunkwan University, 2066 Seobu-ro, Jangan-gu, Suwon, Gyeonggi-do, 16419, Republic of Korea.
Center for Multidimensional Carbon Materials (CMCM), Institute for Basic Science (IBS), Ulsan, 44919, Republic of Korea.
Adv Mater. 2017 Oct;29(39). doi: 10.1002/adma.201606433. Epub 2017 Aug 28.
A systematic modulation of the carrier type in molybdenum ditelluride (MoTe ) field-effect transistors (FETs) is described, through rapid thermal annealing (RTA) under a controlled O environment (p-type modulation) and benzyl viologen (BV) doping (n-type modulation). Al O capping is then introduced to improve the carrier mobilities and device stability. MoTe is found to be ultrasensitive to O at elevated temperatures (250 °C). Charge carriers of MoTe flakes annealed via RTA at various vacuum levels are tuned between predominantly pristine n-type ambipolar, symmetric ambipolar, unipolar p-type, and degenerate-like p-type. Changes in the MoTe -transistor performance are confirmed to originate from the physical and chemical absorption and dissociation of O , especially at tellurium vacancy sites. The electron branch is modulated by varying the BV dopant concentrations and annealing conditions. Unipolar n-type MoTe FETs with a high on-off ratio exceeding 10 are achieved under optimized doping conditions. By introducing Al O capping, carrier field effect mobilities (41 for holes and 80 cm V s for electrons) and device stability are improved due to the reduced trap densities and isolation from ambient air. Lateral MoTe p-n diodes with an ideality factor of 1.2 are fabricated using the p- and n-type doping technique to test the superb potential of the doping method in functional electronic device applications.
本文描述了通过在受控 O 环境下（p 型调制）和苯甲脒（BV）掺杂（n 型调制）进行快速热退火（RTA），对二碲化钼（MoTe ）场效应晶体管（FET）中的载流子类型进行系统调节。然后引入 Al O 盖帽来提高载流子迁移率和器件稳定性。研究发现，MoTe 在高温（250°C）下对 O 非常敏感。通过在不同真空度下进行 RTA 退火的 MoTe 薄片中的电荷载流子在主要为原始 n 型双极性、对称双极性、单极性 p 型和简并型 p 型之间进行调节。MoTe 晶体管性能的变化被证实源于 O 的物理和化学吸附和解离，尤其是在碲空位处。通过改变 BV 掺杂剂浓度和退火条件来调节电子支。在优化的掺杂条件下，实现了具有超过 10 的高开关比的单极性 n 型 MoTe FET。通过引入 Al O 盖帽，由于陷阱密度降低和与环境空气隔离，载流子场效应迁移率（空穴为 41cm V s ，电子为 80cm V s ）和器件稳定性得到提高。使用 p 型和 n 型掺杂技术制造横向 MoTe p-n 二极管，理想因子为 1.2，以测试掺杂方法在功能电子器件应用中的优异潜力。
