十八硫醇與十八烯分子藉由一步化製成自組裝於矽(111)表面的製備與鑑定
Abstract
在之前的文獻中,單層自組裝分子膜在矽化氫表面的成長製程總是先進行氧化矽的蝕刻,使成為氫化矽表面,然後再將氫化矽置入充滿惰性氣體的反應瓶中進行分子自組裝反應,在這過程中,不可避免地,氫化矽表面會與空氣接觸,使的氫化矽在轉移的過程中會被氧化或吸附空氣中的氧氣,影響分子膜的成長。
本篇論文探討藉由兩層溶液的系統來改良分子自組裝製程,兩層溶液系統的組成是由上層的有機層與下層的水相層所組成,藉由此系統,在下層蝕刻完成的矽化氫將不必經過空氣而進入有機相溶液,進而進行自組裝分子膜反應。反應完成的自組裝分子膜藉由水滴接觸角來判斷成膜品質,而原子力顯微鏡則用來觀察分子膜表面狀態,橢圓儀測量厚度和IR來鑑定分子官能基,另外,X光光電子能譜儀可用來鑑定矽表面的氧化狀態。
我們利用octadecylthiol和octadecene來進行自組裝反應,實驗結果顯示octadecylthiol及octadecene分子膜的水滴接觸角分別達到101度及102度,表現出疏水的性質。另外透過AFM的表面鑑定,兩者在表面構形上皆呈現階梯狀的形貌,與蝕刻過的氫化矽表面有同樣的構形,不過粗度卻下降些許,顯示分子膜的存在;膜厚的部分大約在2奈米左右,而IR的官能基鑑定也證實CH3及CH2的存在,另外X光光電子能譜儀顯示C 1s的訊號,以上的資訊都顯示分子膜確實存在於氫化矽上。
另外,為了測試分子膜對氫化矽的保護效果,我們將分子膜修飾後的矽化氫置於空氣中一天到七天,然後藉由XPS觀察矽的氧化程度,結果顯示我們所修飾的分子膜有抗氧化能力。透過以上的量測和鑑定,我們可以確認利用兩層溶液的方法,可以成功的製備單層分子膜於氫化矽表面,並且達到抗氧化效果
In previous studies of SAMs on oxide-free Si(111), the SAM procedures always begin at the etching of the silicon surface; afterward, the etched silicon wafers are enclosed in reaction vase which provides inner surrounding to avoid SiOx forming while SAMs molecules react with silicon. In this work, we utilized a two-layer system which consists of organic phase and aqueous phase to proceed the SAM process without attachment to air. And the characterization of composition of SAM was carried out with X-ray photoelectron spectroscopy (XPS), atomic force microscopy (AFM), water contact angle (CA), and attenuated total reflectance infrared spectroscopy (ATR-IR). The result of contact angle shows that our SAMs possess hydrophobic property that the angle is 102゚ for octadecene (ODC) SAMs and 101゚for octadecythiol (ODT) SAMs. The AFM images show the step by step morphologies of both ODC and ODT SAMs. The XPS data show nearly no remaining silicon oxide in the Si 2p region (95-104 eV) from 1day to 7 days oxidation test. According to these data, we successfully fabricated a monolayer on oxide-free Si(111) surface, and our strategy of one-step method can be applied on the fabrication of ODT and ODC SAMs on oxide-free Si(111) surface. The one-step method providing an oxygen free surroundings can be applied on many surface-modification manufactures of semiconductors in the future.
In previous studies of SAMs on oxide-free Si(111), the SAM procedures always begin at the etching of the silicon surface; afterward, the etched silicon wafers are enclosed in reaction vase which provides inner surrounding to avoid SiOx forming while SAMs molecules react with silicon. In this work, we utilized a two-layer system which consists of organic phase and aqueous phase to proceed the SAM process without attachment to air. And the characterization of composition of SAM was carried out with X-ray photoelectron spectroscopy (XPS), atomic force microscopy (AFM), water contact angle (CA), and attenuated total reflectance infrared spectroscopy (ATR-IR). The result of contact angle shows that our SAMs possess hydrophobic property that the angle is 102゚ for octadecene (ODC) SAMs and 101゚for octadecythiol (ODT) SAMs. The AFM images show the step by step morphologies of both ODC and ODT SAMs. The XPS data show nearly no remaining silicon oxide in the Si 2p region (95-104 eV) from 1day to 7 days oxidation test. According to these data, we successfully fabricated a monolayer on oxide-free Si(111) surface, and our strategy of one-step method can be applied on the fabrication of ODT and ODC SAMs on oxide-free Si(111) surface. The one-step method providing an oxygen free surroundings can be applied on many surface-modification manufactures of semiconductors in the future.
Description
Keywords
自組裝分子膜, 十八硫醇, 十八烯, 矽(111), self-assembled monolayer, octadecylthiol, octadecene, Si(111)