2004年曼徹斯特大學物理學家Andre Konstantin Geim和Konstantin Novoselov團隊利用機械剝離法，運用膠帶反覆黏貼，將單層的石墨烯從石墨中剝離出來，此後便開啟了大量二維材料方面的研究，近年來最受矚目的材料便是過渡金屬二硫族化物(TMDs)。本論文利用WS2/WSe2梳狀異質結構作為與金屬接觸的部分，製作了NMOS與PMOS。其Type-II的能帶結構造成大量的電荷轉移，電子由WSe2轉移至WS2，而電洞由WS2轉移至WSe2，由此改善了以往接觸能障過大的問題。本論文中WS2電晶體其蕭特基能障為28 meV，而WSe2電晶體其蕭特機能障為 34 meV，載子遷移率分別為6.61 cm2
/V ·s與1.3 cm2
/V ·s，此外我們也有進行TLM量測，照光前接觸電阻為891 kΩ • µm，照光後接觸電阻降為585 kΩ • µm，這是由於照光後產生的電子電洞對被內建電場分離，電荷的轉移使得能障進一步下降。

In 2004, physicists Andre Konstantin Geim and Konstantin Novoselov from the University of Manchester utilized a mechanical exfoliation method, repeatedly using adhesive tape to peel off single layers of graphene from graphite, thus initiating extensive research on two-dimensional materials. In recent years, one of the most prominent materials in this field is Transition Metal Dichalcogenides (TMDs). In this work, a WS2/WSe2 strip shape heterostructure was employed as the contact region with metals to fabricate NMOS and PMOS devices. The Type-II band structure resulted in charge transfer, with electrons transferring from WSe2 to WS2 and holes transferring from WS2 to WSe2, thereby reduce the contact barrier. In this study, the Schottky barrier of the WS2 transistor was measured to be 4meV, while the Schottky barrier of the WSe2 transistor was 18meV. The carrier mobility was reported as 6.61 cm2
/V ·s and 1.3 cm2
/V ·s for WS2 and WSe2, respectively. Additionally, Transmission Line Measurement (TLM) was also conducted, showing that the contact resistance decreased from 891 kΩ • µm before illumination to 585 kΩ • µm after illumination. This decrease can be attributed to the separation of electron-hole pairs generated by illumination, facilitated by the built-in electric field, resulting in a further reduction of the barrier height.

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