以蠶絲蛋白為閘極介電層之肽菁銅有機薄膜電晶體的製備

Fabrication of copper phthalocyanine based organic thin-film transistors with silk fibroin as the gate dielectric

林怡婷(Yi-Ting Lin)

指導教授 ： 黃振昌

國立清華大學/工學院/材料科學工程學系/碩士(2013年)

摘要

本論文以蠶絲蛋白作為閘極介電層，P型有機半導體材料CuPc作為主動層，製作有機薄膜電晶體(Organic Thin Film Transitors, OTFTs)，探討不同蒸鍍基板溫度、半導體膜厚以及結構下，元件特性的改善。在基板溫度90℃，CuPc膜厚45 nm條件下，元件載子遷移率提升至0.96 cm2V-1s-1，開關特性比(on/off ratio)為1.1×103，臨界電壓為-2.08V，此電性結果是本研究最佳的製程參數。
利用原子力顯微鏡(AFM)、低掠角X光繞射儀(GIXRD)來探討薄膜表面形貌以及結晶情形，印證元件的電性結果。從AFM分析圖中，可發現在不同基板溫度下蒸鍍，CuPc薄膜晶粒特徵從30℃的針狀(needle-like)到90℃則變成棒狀(rod-like)。將CuPc分別沉積在蠶絲蛋白表面和SiO2上，從GIXRD分析圖可知，在蠶絲蛋白表面的結晶程度較佳，隨著基板溫度提高，結晶程度也提升，可促進載子傳輸，使元件的載子遷移率提升。
以蠶絲蛋白為閘極介電層的元件具有非理想效應的遲滯現象，在蠶絲蛋白表面加入鈍化層長鏈烷基TTC後，遲滯現象大幅減少，元件穩定度提升。
在雙載子有機薄膜電晶體(Ambipolar OTFTs)方面，採用雙層型(bilayer)的結構，利用CuPc/F16CuPc異質結構，以PET作為基板，符合有機薄膜電晶體可撓式元件發展的需求，調變下層F16CuPc的膜厚，推得當45 nm CuPc/30 nm F16CuPc時，電子和電洞載子遷移率較為相近，電子和電洞遷移率分別是0.14和0.03 cm2V-1s-1。
當在蠶絲蛋白表面加上一層TTC薄膜，製作45nm CuPc/17nm F16CuPc/TTC雙載子有機薄膜電晶體，有明顯的Ambipolar特性出現，電子和電洞載子遷移率分別是0.035和0.47 cm2V-1s-1。

關鍵字

有機薄膜電晶體 ； CuPc ； 蠶絲蛋白 ； 雙載子

並列摘要

In this thesis, we have used silk fibroin as the gate dielectric layer and CuPc as the p-type semiconductor material to fabricate organic thin-film transistors (OTFTs). Experimental parameters include the substrate temperature during thermal deposition, CuPc thickness and the passivation layer. When the depositing substrate temperature is 90℃ and the thickness of CuPc is 45nm, a field-effect mobility value of 0.96 cm2V-1s-1, an on/off ratio of ca. 1.1x103 and a threshold voltage of -2.08V are achieved.
AFM and GIXRD were used to characterize the CuPc thin film. The morphology of the CuPc thin film strongly depends on temperature, specifically in the grain size and shape. At 30℃, the CuPc grains are needle-like. When the temperature increases to 90℃, the CuPc grains become rod-like. When CuPc is deposted on silk fibroin, the degree of crystallization of CuPc thin film is better than that on the untreated SiO2.
TTC was used as the passivation layer to reduce the hysteresis loop and to increase the stability of the device.
Ambipolar OTFTs with a bilayer of CuPc and F16CuPc was also fabricated. A bilayer of 45nm CuPc/ 30nm F16CuPc exhibits the best performance of ambipolar characteristics. The field-effect mobilities of electrons and holes are 0.14 and 0.03 cm2V-1s-1 respectively.
With the assistance of the TTC passivation layer, 45 nm CuPc/ 17 nm F16CuPc ambipolar exhibits better ambipolar characteristics. The field-effect mobilities of electrons and holes are 0.035 and 0.47 cm2V-1s-1 respectively.

並列關鍵字

OTFTs ； CuPc ； silk fibroin ； ambipolar

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