Murastov Gennadiy, Aslam Muhammad Awais, Leitner Simon, Tkachuk Vadym, Plutnarová Iva, Pavlica Egon, Rodriguez Raul D, Sofer Zdenek, Matković Aleksandar
Department Physics, Mechanics and Electrical Engineering, Montanuniversität Leoben, Franz Josef Strasse 18, 8700 Leoben, Austria.
Laboratory of Organic Matter Physics, University of Nova Gorica, Vipavska 13, SI-5000 Nova Gorica, Slovenia.
Nanomaterials (Basel). 2024 Mar 6;14(5):481. doi: 10.3390/nano14050481.
Tungsten diselenide (WSe2) has emerged as a promising ambipolar semiconductor material for field-effect transistors (FETs) due to its unique electronic properties, including a sizeable band gap, high carrier mobility, and remarkable on-off ratio. However, engineering the contacts to WSe2 remains an issue, and high contact barriers prevent the utilization of the full performance in electronic applications. Furthermore, it could be possible to tune the contacts to WSe2 for effective electron or hole injection and consequently pin the threshold voltage to either conduction or valence band. This would be the way to achieve complementary metal-oxide-semiconductor devices without doping of the channel material.This study investigates the behaviour of two-dimensional WSe2 field-effect transistors with multi-layer palladium diselenide (PdSe2) as a contact material. We demonstrate that PdSe2 contacts favour hole injection while preserving the ambipolar nature of the channel material. This consequently yields high-performance -type WSe2 devices with PdSe2 van der Waals contacts. Further, we explore the tunability of the contact interface by selective laser alteration of the WSe2 under the contacts, enabling pinning of the threshold voltage to the valence band of WSe2, yielding pure -type operation of the devices.
二硒化钨（WSe₂）因其独特的电子特性，包括可观的带隙、高载流子迁移率和显著的开关比，已成为一种有前途的用于场效应晶体管（FET）的双极性半导体材料。然而，对WSe₂的接触进行工程设计仍然是一个问题，高接触势垒阻碍了其在电子应用中充分发挥性能。此外，有可能调整与WSe₂的接触，以实现有效的电子或空穴注入，并因此将阈值电压固定在导带或价带。这将是在不掺杂沟道材料的情况下实现互补金属氧化物半导体器件的方法。本研究考察了以多层二硒化钯（PdSe₂）作为接触材料的二维WSe₂场效应晶体管的行为。我们证明，PdSe₂接触有利于空穴注入，同时保持沟道材料的双极性特性。这进而产生了具有PdSe₂范德华接触的高性能p型WSe₂器件。此外，我们通过对接触下方的WSe₂进行选择性激光改性来探索接触界面的可调性，从而将阈值电压固定在WSe₂的价带，实现器件的纯p型操作。
