| 摘要: | 近幾年矽基電子元件 (Si-based electronics) 隨著元件尺寸微縮 (scaling down) ，除了改良電晶體結構之外，尋找高效能次世代電子元件材料也是積極開發的目標；而二維材料因厚度只有幾個的原子層以及多樣且優異的材料特性吸引各大領域爭相研究。其中石墨烯 (graphene) 雖然具有優異的電子特性但是本質上為無能隙 (gapless) 材料以及高品質石墨烯合成技術產能仍需改善。為了解決前述問題，在此將多孔隙 (porosity) 材料與銅箔堆疊繞捲於一吋傳統水平爐管，能有效提升爐管空間使用率。並且藉由孔隙材料幫助氣體擴散至整個結構中，使產率 (yield) 達到2348 cm2/h為一般水平堆疊的四倍；而當加熱爐管系統延伸至八吋大小，產率能達到至少18 m2/h。為了研究異質原子參雜石墨烯的電性調控，利用高能量離子佈植技術 (keV ion implantation) ，將磷離子 (phosphorous-ion) 注入於金薄膜披覆的大面積石墨烯上，藉由此保護層減少注入離子的能量以及降低石墨烯的損傷程度，更能使用此保護層將摻雜石墨烯直接轉印到目標基板上；並且藉由後退火 (post-annealing) 修復晶格結構得到乾淨且低缺陷以及2 – 4個原子百分比的磷摻雜石墨烯。其載子遷移率 (mobility) 仍然可以維持450 cm2/V·s以及4.85 – 4.15 eV的功函數 (work function) 調控；並且在大氣環境下其摻雜效果以及電子特性可以維持至少數個月。此外，由於大多二維材料因能隙小於2 eV因此較難於高電壓元件；而新興的二維材料 – 銻烯 (antimonene) ，因具有2.28 eV寬能隙、優異的電子傳輸特性以及長時間的大氣穩定性，也被譽為下世代元件材料之一。然而，目前所發表的文獻大多以模擬分析為主；合成方法則以分子束磊晶 (molecular beam epitaxy) 以及液相剝離 (liquid-phase exfoliation) 較為廣泛使用，因此所能觀察到的單層銻烯面積過小 (< 1 ?m) 較難用以後續探討材料特性。因此，此研究將藉由調控氣相傳輸沉積法 (vapor transport deposition) 的環境參數並研究各條件對銻烯生長的影響以及機制的探討。從合成的銻烯厚度和面積呈現面積變大也增厚的正相關 (positive correlation) 變化，可以推測銻烯的成長模式偏好為Volmer-Weber的島狀成長；而提升氫氣比例時能有效降地Sb2O3蒸氣比例並增加銻烯的成長密度，但是過多的氫氣也會抑制銻烯的成長。後續使用雙層石墨烯封裝銻烯，藉由封裝退火 (encapsulated annealing) 發現銻烯在400 – 600℃範圍內具有高熱穩定性 (thermal stability) 。本研究中提出的高產率繞捲合成方式以及穩定的離子佈植摻雜方法，可延伸至其他二維材料進行高產率合成以及可控性摻雜，並相容現有的半導體製程；以及二維半導體材料的合成機制探討，有利於未來新穎奈米電子材料以及元件製程開發。;Due to the upcoming physical limit in the scaling down of semiconductor components, the killer material is necessary and urgent. Hundreds of two-dimensional (2D) materials expect to apply in various applications with their specific outstanding properties. Among them, graphene has been considered the promising material of electronic and optoelectronic components due to its excellent material properties. However, even graphene has outstanding electrical properties, tuning the electronic structures is an urgent issue due to the essential gapless. More important, the high-yield synthesis technology of high-quality graphene still needs to be developed. Herein, high porosity material is helically stacked with Cu foil for increasing furnace tube utilization. Also, with the computational fluid dynamics simulation, the porosity material is the critical component for reaction gas to diffuse inside the whole helical structure. Thus, the yield of a traditional 1-inch furnace is 2348 cm2/h is almost 4 times higher than the vertically stacked method. When the size of the furnace system is up to 8-inch, the yield can be up to at least 18 m2/h. Next, the industrial-level ion implantation approach was proposed to implant phosphorous ions, where phosphorus doping can provide more effective n-type behavior in graphene. Also, the gold protecting layer is employed to decline the keV implant energy and reduce the damage caused by the ions together with the post-annealing to heal the crystal defect. Thus, the low-damaged graphene with 2 – 4 at% doping concentration can obtain. In addition, the doped graphene with tunable work functions (4.85 – 4.15 eV) and stable n-type doping while keeping high carrier mobility, 450 cm2/V·s, are realized. Besides, the emerging two-dimensional material, antimonene, has attracted intensive attention because of the 2.28 eV bandgap, excellent electrical properties, and high atmospheric environmental stability. Due to the lack of a reliable synthesis method, the current reports focused on the theoretical calculation. Therefore, in this study, the vapor transport deposition was applied to exploiting the synthesis mechanism of antimonene film by the comprehensive parametric investigation, including the pressure, temperature, powder weight, and growth time. This study contributes essential results to advance the growth mechanism based on vapor transport deposition. It found out that antimonene tends to form the single-crystal structure than the layered structure; the adatom cohesive between Sb atoms is considered to be stronger than surface adhesive force. Therefore, the growth model of Sb thin-film growth belongs to the Volmer-Weber mode, where it limits the increase of lateral size when extending growth time and blocks the continuous synthesis of monolayer films. Also, the density of the single-crystal antimonene could suppress by regulating the hydrogen flow, which increases the Sb vapor by reducing the Sb2O3. Besides, the overflowing hydrogen could limit the synthesis of single-crystal antimonene due to the abundant by-product (H2O) reacting and etching or saturating the edge of Sb flake at down steam. In addition, the synthesized single-crystal antimonene encapsulated in bilayer graphene can observe the stability of antimonene near the vaporized temperature, 400 to 600℃. This work contributes to tailoring 2D materials′ electrical properties with an exceptional low defect density, suggests surpassing potential for integrating with modern semiconductor technology for next-generation 2D-based nanoelectronics, and provides the investigation of synthesis mechanism on the novel semiconductor materials. |
