二硫化鉬（MoS₂）具有原子級厚度、半導體能隙與良好的閘極調控能力，被視為具潛力之二維半導體材料。然而，在實際元件中，金屬與 MoS₂ 接觸界面常受到費米能階釘紮、界面態與蕭特基能障影響，使載子注入效率受到限制，進而影響元件之導通電流與輸出特性。本研究於 Au/MoS₂ 接觸界面中導入超薄硒（Se）中介層，製作 Au/Se/MoS₂ 接觸結構，並探討 Se 中介層對 MoS₂ 材料特性、接觸能階排列與電晶體電性傳輸之影響。 首先，利用 Raman 與 PL 光譜分析 Se 中介層與 Au 電極沉積後 MoS₂ 之晶格振動與光學特性變化，以觀察製程後可能產生之應力、電荷轉移與界面交互作用。接著，本研究製作背向閘極 MoS₂ 電晶體，並透過轉移特性與輸出特性分析 Se 中介層對 Au/MoS₂ 接面載子傳輸行為之影響。電性結果顯示，隨著 Se 中介層厚度增加，元件導通電流逐漸下降，且輸出特性於低偏壓區呈現較明顯之非線性，顯示 Se 中介層可能使接觸端載子注入受到更強限制。為進一步定量分析接觸能障變化，以變溫電性量測與 Arrhenius 分析萃取蕭特基能障。結果顯示，元件之平帶蕭特基能障呈現隨 Se 厚度增加而上升之趨勢。Se 中介層會提高 Au/MoS₂ 接面之電子注入障礙，對應電性中觀察到之電流下降與接觸限制增強。Au–MoS₂ / Au/Se–MoS₂ 非對稱接觸元件中，2 nm Se 非對稱元件之理想因子約為 1.31，較 1 nm Se 元件之 2.22 更接近理想二極體行為，且與其較高整流比相互呼應。此結果說明適當厚度之 Se 中介層可形成較明顯且較穩定的非對稱接觸能障，使元件呈現較佳之整流特性與二極體傳輸行為。;Molybdenum disulfide (MoS₂) is a promising two-dimensional semiconductor; however， its device performance is often limited by metal/MoS₂ contact barriers and Fermi-level pinning. In this study， an ultrathin selenium (Se) interlayer was inserted into the Au/MoS₂ contact interface to form Au/Se/MoS₂ junctions， and its influence on energy-level alignment， Schottky barrier height， and electrical transport behavior was investigated. Raman and photoluminescence measurements indicate that Au deposition and Se insertion modify the lattice vibration and optical response of MoS₂， suggesting interfacial interactions and local changes in the MoS₂ environment. UPS analysis shows that the Se interlayer shifts the Fermi level farther from the MoS₂ conduction band edge， with (EC-EF) increasing from approximately 0.09 eV for Au–MoS₂ to 0.20 eV for Au/Se–MoS₂， indicating an increased electron injection barrier. Back-gated MoS₂ transistors with Se interlayers maintained n-type behavior， but their on-current decreased and output characteristics became more nonlinear as the Se thickness increased. Temperature-dependent measurements further confirmed that the flat-band Schottky barrier height increased from 97 meV for the Au–MoS₂ device to 145， 242， and 334 meV for 1， 2， and 3 nm Se interlayers， respectively. Asymmetric Au–MoS₂/Au/Se–MoS₂ devices exhibited rectifying behavior， with maximum rectification ratios of approximately 480 and 630 for 1 and 2 nm Se interlayers. These results demonstrate that ultrathin Se acts as a barrier-modulating interlayer and can effectively tune the electrical transport properties and rectifying behavior of Au/MoS₂ junctions.
