一維奈米材料與半導體材料表面摩擦性質之研究

Abstract

本文主要針對一維奈米材料與半導體表面之間的摩擦與吸附性質來做研究與討論，一維奈米材料將被放置在原子力顯微鏡中，利用原子力顯微鏡側向操控的特性，進而找出奈米管與半導體表面之間的摩擦吸附性，不但在設計奈米元件上有所助益，甚至可應用到能量儲存的元件上。本實驗將採用多層奈米碳管和氮化硼奈米管為實驗對象，並使用矽和二氧化矽做為半導體的基材，經側向操控後，奈米管於半導體表面上滑移轉動，而奈米材料與半導體之間的摩擦吸附性質將在文中一一討論。 第一利用原子力顯微鏡研究多層奈米碳管與二氧化矽的摩擦吸附性質。利用原子力顯微鏡的側向操控的特性，可觀察到多層奈米碳管於二氧化矽上滑移轉動，同步取得側向力曲線的變化，再經由整理之後，得知兩者之間的吸附力，再根據多層奈米碳管與二氧化矽的接觸面積，即可計算出多層奈米碳管與二氧化矽之間的剪應力，大約是60 MPa。再依據實驗結果，可發現剪應力與多層奈米碳管轉動角度是線性相關，我們也將在文中歸納出施力點與轉動支點的關係，再針對多層奈米碳管的轉動現象與吸附性逐步探討。 第二接著探討氮化硼奈米管與矽晶片的摩擦吸附性。同樣利用原子力顯微鏡的側向操控功能，也可以在實驗的過程中，也可觀察出氮化硼奈米管於矽的表面上滑移轉動情形後，藉由所得的側向力曲線得知，得知兩者之間的吸附力，再配合修正之後的接觸面積，與滑移轉動的面積，可以計算出氮化硼奈米管與矽晶片之間的剪應力與比滑移能量損耗，大約是0.5 GPa與0.2 J/m2，然後再與其他相關文獻比較之後，結果發現氮化硼奈米管吸附能力比較好，因此氮化硼奈米管非常適合運用於儲氫元件上。 最後本研究的結果驗證原子力顯微鏡可以拿來操控奈米材料，而且能精準的定位奈米材料的位置，對於研究奈米科技可以提高準確度，另外期望MWCNT與BNNT的研究結果，可以作為日後設計奈米元件的依據。

The target of this dissertation is the tribological interaction between one dimension nano material and semi-conductor surface. One dimension nano materials are manipulated in an atomic force microscope (AFM), and tribological properties of nanotube-surface are discovered. So we can use the information of the tribological properties of nanotube-surface to design nano devices or energy storage. In our experiments, we adopted the multi-walled carbon nanotubes (MWCNTs) and boron nitride nanotubes (BNNT) to be one dimension nano material. Silica and silicon which properties both are semi-conductor are used as substrate materials. Therefore, we discussed the tribological interaction between one dimension nano material and semi-conductor surface in detail. The tribological interaction between MWCNTs and silica surface using lateral manipulation in the AFM. The MWCNT is mechanically manipulated by a pyramidal silicon probe of an AFM using the same scan mechanism as in the imaging mode. With a controlled normal force of the AFM probe, it was found that lateral force applied to the MWCNT could overcome the tribological adhesion between MWCNT and silica surface, causing individual MWCNT to rotate on the silica. According to the results, the shear stresses due to tribological interacting with the MWCNTs and the silica are 59.6 MPa and 64.8 MPa for the MWCNT 1 (100 nm diameter) and the MWCNT 2 (60 nm diameter), respectively. Experimental results show that the shear stress increases with the increasing rotation angle for each manipulation, from which we determine the linear fitting function. In addition, we determine the relationship between push point and pivot point to realize the rotation behavior. The implications of tribological interaction between the MWCNTs and silica surface are discussed in detail. The tribological interaction between BNNTs and silicon was studied with lateral manipulation in AFM. The BNNTs was mechanically manipulated by the lateral force of an AFM pyramidal silicon probe using the scan mechanism in the imaging mode. With a controlled normal force of the AFM probe and the lateral motion, the lateral force applied to the BNNTs could overcome the tribological interaction between BNNTs and silicon surface. The individual BNNT is forced to slide and rotate on the silicon surface. Based on the recorded force curve, the calculated shear stress due to surface adhesion is 0.5 GPa. And the specific sliding energy loss is 0.2 J/m2. Comparing BNNTs and CNTs [24], the shear stress and specific sliding energy loss of BNNTs are an order of magnitude larger than that of CNTs. Therefore, the results show that the tribological interaction between BNNTs and silicon surface is higher than that of CNTs.