電子束轟擊對背向閘極式單層二硫化鉬元件光學及電性之探討

Abstract

本研究在於利用電子束轟擊調變二硫化鉬之能帶結構及電子傳輸特性，藉由觀察PL光譜的變化以對應電性的傳輸特性改變。透過電子束轟擊二硫化鉬產生硫空缺，利用拉曼及PL光譜量測進而發現半高寬及Trion峰值訊號的改變，且觀察到PL藍移的現象，藉由不同電子束劑量對應到的PL特徵峰值位移及激子(excitonA、B)及Trion特徵峰值比例增減及對照三點電性量測結果，明顯改變電子傳輸性質及能力。在電子束特定劑量下轟擊，光學性質中PL光譜上藍移最大值及拉曼的半高寬最大值。電子傳輸性質由初始狀態下為P型，在轟擊之下轉為N型並且電子傳輸能力Ion / Ioff 由初始狀態 102在電子束的轟擊之下顯著提升至106，增強四個數量級。由實驗結果可以得知，藉由電子束的劑量調變，在二硫化鉬中產生適當的硫空缺不但改變電子躍遷行為及能帶結構，並能大幅提升二硫化鉬電子傳輸能力。未來能應用於光電元件上，調變二維材料元件的發光特性及增益光電晶體的電性傳輸。

This study consists in the use of electron beam bombardment to modify the energy band structure and electron transport properties of molybdenum disulfide, by observing changes in the PL spectrum to correspond to electrical transmission characteristics. Sulfur vacancy was generated by bombardment of molybdenum disulfide by electron beam, and the change of FWHM and Trion peak signal was found by Raman and PL spectroscopy, and the phenomenon of PL blue shift was observed, and PL corresponding to different electron beam doses was observed. The characteristic peak displacement and exciton A,exciton B) and Trion characteristic peak ratio increase and decrease and the comparison of three-point electrical measurement results significantly change the electron transport properties and capabilities. Bombardment at a specific dose of electron beam, the maximum value of the blue shift on the PL spectrum and the maximum half width of the Raman in the optical properties. The electron transport property is P-type from the initial state, and is converted to the N-type under bombardment and the electron transport capability Ion / Ioff is significantly increased from the initial state 102 to 106 under the bombardment of the electron beam, increasing by four orders of magnitude. It can be known from the experimental results that the appropriate sulfur vacancies in the molybdenum disulfide not only change the electronic transition behavior and the energy band structure, but also greatly enhance the electron transporting ability of molybdenum disulfide by the dose modulation of the electron beam. In the future, it can be applied to optoelectronic components to modulate the luminescence properties of two-dimensional material components and the electrical transmission of gain optoelectronic crystals.