開發可撓性導電薄膜於光電元件之研究

Abstract

本研究主要為利用奈米碳管在軟性基板聚二甲基矽氧烷(Polydimethylsiloxane, PDMS)上製作導電電極，分別利用掀離法(Lift-off)和電泳鍍法(Electrophoresis plating)將奈米碳管在軟性基板上圖案化，並於光電元件之應用。本研究利用奈米碳管粉末，配合十二烷基硫酸鈉(Sodium dodecyl sulfate, SDS)作其分散劑以找尋最佳之導電和製作濃度，再分別利用掀離法和電泳鍍法探討其最佳之製程參數。在掀離法方面，先利用大氣電漿將PDMS表面親水化，再利用黃光微影直接在表面進行圖案化，最後利用浸泡的方式將奈米碳管沉積在PDMS表面，利用不同的浸泡方式和熱烤時間得到最佳之奈米碳管圖案化。另外，在電泳鍍方面，設定不同的電壓和時間來取得最佳之沉積結果，最後再將其轉印到PDMS基板上。試片完成後，利用四點探針和資料蒐集器測量試片的導電率，並利用掃描式電子顯微鏡(Scanning electron microscope, SEM)對奈米碳管的表面進行量測以檢測其經過攪拌後是否有產生團聚等現象，而紅外光譜(Fourier transform infrared spectroscopy, FTIR)和拉曼光譜(Raman spectrum)主要為對奈米碳管溶液進行分析，以測得溶液在經過分散劑後其奈米碳管是否改變。導電薄膜的製作完成後，將為先利用簡單的方式以檢測其導電能力，最後將導電薄膜應用於觸控和壓力微感測器。

The aim of this study is to use a simple process with a lift-off and electrophoresis plating technique to fabricate the conductive thin film on flexible substrate with CNTs (Carbon nanotubes). The CNTs are studied as the electrode material and have the potential owing to its high conductivity and the convenience of the fabricating process. To deploy the CNTs, we apply SDS (Sodium dodecyl sulfate) as the dispersant. Here, the substrate is employed PDMS (Polydimethylsiloxane), which is a group of polymeric organosilicon compounds. For the direct photolithography on PDMS, the surface of PDMS should be not only hydrophilic, but more flat so that the photoresist could be spun on the surface evenly. After the process of photolithography, the patterns of electrode can be defined on the surface. Based on this direct process, the complicated electrode patterns can be easily defined and its pattern would not be deformed. In electrophoretic plating technique, by applying different voltages and time for abtained optimized parameters, it can be deposited CNTs on PDMS well. After depositing, the CNTs can be transferred to PDMS. Finally, we use SEM, FTIR, and Raman Spectrum for measuring the surface and properties of CNT. Therefore, this study provides a novel and simple way to fabricate the conductive thin films and through the complicated electrode pattern defined, the application of thin films for photoelectric sensors could be easily used in this work.