研究二維硫硒化鉬之特性及其用於金氧半互補式電晶體之設計

Abstract

近幾年出現的非對稱過渡金屬二硫屬化物(JTMD)因其卓越的光學和電學特性，吸引了廣泛關注。與傳統二維材料相比，JTMD額外的本質偶極矩可以產生 n 型和 p 型接觸，可用於太陽能電池和針型二極體等器件。在本論文中，我們利用這一特性來構建同時包含 n 型和 p 型的金屬氧化物半導體互補式場效電晶體。首先，我們通過密度泛函理論計算研究了三層二維硫硒化鉬(MoSSe)中的自發偶極矩電場強度。再來，我們探討 MoSSe 的自發偶極矩與不同金屬在接觸時產生的能帶彎曲，並探討電子和電洞的如何在介面累積而形成 p 型、n 型甚至歐姆接觸。利用後續這該接觸特性，透過二维有限元的泊松漂移擴散求解器進行電晶體元件模擬，透過這些模擬幫助我們構建最佳的互補型場校電晶體維度。我們最終的研究結果顯示，透過適當的設計，我們可以只使用單一個 JTMD 材料作為通道層，設計同時包含 n 型與 p 型的互補型場校電晶體，且無需額外掺雜就能形成高濃度載子區域。除此之外，我們也針對二維硫硒化鉬進行光學吸收性值的探討，並將吸收相關之關鍵參數取出，以供未來光電元件模擬做使用。

Janus transition metal dichalcogenides (JTMDs) have attracted extensive attention due to their exceptional optical and electrical properties. The extra intrinsic dipole moment of JTMDs can generate n-type and p-type contacts, which can be used for devices such as solar cells and pin diodes. Our work explores JTMDs for complementary metal-oxide-semiconductor field-effect transistors (CMOSFETs), enabling n- and p-type channels in a single material. Firstly, we investigate the spontaneous dipole field strength in layered MoSSe through density-functional theory. The MoSSe spontaneous polarization influences how it interacts with contacts, leading to Ohmic, p-type, or n-type contact formations. Utilizing these contact properties, we employed a finite element Poisson-drift-diffusion two-dimensional method to simulate the transistor device, and these simulations guided us to design the best dimensions for CMOSFETs. Our final results demonstrate that, through appropriate design, we can design CMOSFETs containing both n-type and p-type transistors using only a single JTMD material as the channel layer, and form high-carrier-density regions without additional doping. In addition, we investigated the optical absorption properties of two-dimensional MoSSe, extracting key absorption-related parameters for use in future optoelectronic device simulations.