在本研究中，我們報導一種在室溫下透過聚苯乙烯奈米球微影術結合金屬輔助催化蝕刻法與電化學蝕刻法的新穎製程技術，成功在(001)矽單晶基材上以一步驟、安全以及低成本的方式製備出大面積規則準直之矽單晶奈米管陣列結構，不需要額外複雜且昂貴的光照顯影設備以及技術，克服由先前文獻報導製備矽晶奈米管所遭遇到的製程問題。在此新穎製程方法中，我們首先在矽晶基材表面形成尺寸均勻且規則有序之內含奈米尖孔洞之蜂巢狀金薄膜結構作為後續催化與蝕刻位置，透過調控聚苯乙烯奈米球之尺寸與電化學蝕刻時間可以分別控制矽單晶奈米管的外徑以及長度。再經由SEM、TEM影像圖與其相對應之電子選區繞射圖譜鑑定分析可得知所製備出之矽單晶奈米管具有高度準直性且為單晶結構。而所獲得之高長寬比矽單晶奈米管因中空結構能避免孔洞間的空氣薄膜逸出，其疏水性質相較於同樣利用金屬輔助電化學蝕刻法所製備之相同尺寸矽晶奈米線更加優異。在波長範圍400-800 nm的光譜量測結果顯示，因矽單晶奈米管可視為是由奈米線與奈米洞共同組成之複合式奈米材料，相較於矽晶基材與矽單晶奈米線擁有更優異的光吸收能力。實驗結果呈現出令人興奮的前景，所提出之新穎製程技術及結構，相信對各式先進一維奈米中空半導體元件之開發將能提供製程改善之參考。;In this study, we propose and demonstrate a novel and room-temperature approach combing the polystyrene nanosphere lithography, metal-assisted catalyzed etching and electrochemical etching process. This method successfully fabricates large-area and well-order arrays of vertically-aligned silicon nanotubes on (001)Si substrate. In contrast to earlier techniques, the new approach proposed in this study does not require the use of toxic chemicals, expensive facilities and metal hard masks or sacrificial templates. In this approach, a unique, hexagonally-ordered Au honeycomb consisted of nanohole patterning with uniform size and spacing was first produced on the surface of (001)Si substrate. The Au honeycomb used as the catalyst and the nanohole used as initial pits to etch vertically downward into the Si substrate by Au-catalyzed chemical etching and electrochemical etching respectively. The outer diameter and the length of silicon nanotubes are modulated by controlling the size of the polystyrene nanosphere and the etching time. From SEM, TEM and SAED analysis indicated the silicon nanotubes are highly collimated and single crystalline. Comparing with the flat Si substrate and the Si nanowire samples, the H-terminated hydrophobic Si nanotubes with open-ended and uncovered hollow interiors that fabricated in this study can prevent the air from escaping from the structures and exhibit higher water contact angles. The visible light band spectroscopic measurement revealed that the silicon nanotubes considered as a hole-in-wire structure exhibited excellent light absorption characteristics compared to silicon nanowires. The field emission measurement results show that the turn-on field was 7.22 V μm-1, owing to their thick wall. To achieve the excellent electronic field emission devices, there are many aspects that need to be overcome and improved. The obtained results present the exciting prospects that the new approach proposed here can be extended to the design and fabrication of various 1-D hollow semiconductor nanodevices with multi-function.
