臺灣博碩士論文加值系統

　　有機薄膜半導體(Organic thin-flim transistors, OTFTs)擁有容易製造的潛在優勢，結構簡單，製程溫度低，和可彎曲的特性，未來可取代矽電晶體應用於在驅動各式各樣的軟性顯示器。本研究以聚(3-己烷基噻吩) (Poly(3-hexythiophene), P3HT)作為有機半導體，製作有機薄膜電晶體，研究P3HT的薄膜電晶體在不同彎曲的狀態下，其光電特性在不同的彎曲曲率下變化的情形。
　　本論文展示出使用水性聚脲酯(Polyurethane, PU)當作可彎曲式P3HT的有機薄膜電晶體之絕緣層，元件載子遷移率可達1.9×10^-2 cm^2/Vs，並在不同的彎曲曲率下量測電流特性與拉曼光譜圖。從研究結果中發現元件在不同的彎曲曲率下有良好的穩定特性，這個穩定的電流特性對一個驅動元件是很重要的條件；當一個可彎曲的顯示器面板，在被彎曲之後，薄膜電晶體的電性仍能保持，而不會去影響到映像點的區塊，可使顯示器保持原有的品質。

　　Organic thin film transistors (OTFTs) with advantages of easy processing, simple structure, low process temperature, and flexibility can be a candidate as the driver in many kind flexible displays. In this thesis, poly(3-hexythiophene) (P3HT) was used as organic semiconductor to fabricate OTFT on the flexible substrate. The optoelectronic characteristics of OTFTs were studying under various bending conditions.
　　This paper exhibits that the P3HT-based OTFT used polyurethane as gate dielectric layer has mobility of 1.9×10^-2 cm^2/Vs. The electrical characteristics and Raman spectrum were measured at different banding curves. P3HT-based OTFTs have good stability even if they were bended at different bending curves. The stability of electricity characteristics OTFTs is prerequisite for a flexible display to keep the characteristics of OTFs under bending condition High quality of OTFTs on flexible substrate will give rise to high performance quality.

摘要………………………………………………………………………Ⅰ
ABSTRACT………………………………………………………………Ⅱ
致謝………………………………………………………………………Ⅲ
目次………………………………………………………………………Ⅳ
表目錄……………………………………………………………………Ⅵ
圖目錄……………………………………………………………………Ⅶ
第一章　緒論……………………………………………………………1
1.1　有機半導體(organic semiconductor)………………………………1
1.2　水性光學塑膠材料…………………………………………………2
1.3　有機薄膜電晶體(Organic thin-film transistors)……………………3
1.3.1　元件結構…………………………………………………………4
1.3.2　原理………………………………………………………………5
1.3.3　描述有機薄膜電晶體電特性的基本公式………………………7
1.4　研究目的…………………………………………………………10
第二章　P3HT有機薄膜電晶體之元件設計…………………………19
2.1　前言…………………………………………………………………19
2.2　實驗方法……………………………………………………………19
2.2.1　有機材料…………………………………………………………19
2.2.2　樣品設計…………………………………………………………21
2.2.3　樣品製作…………………………………………………………22
2.3　實驗儀器……………………………………………………………23
第三章　P3HT有機薄膜電晶體元件電性分析…………………………44
3.1　前言…………………………………………………………………44
3.2　元件製作……………………………………………………………44
3.3　元件分析……………………………………………………………45
3.3.1　電性分析…………………………………………………………45
3.3.2　拉曼分析…………………………………………………………49
3.3.3　光激發光分析……………………………………………………50
第四章　結論與未來展望………………………………………………66
參考文獻…………………………………………………………………67

表目錄
表1-1　有機半導體與無機半導體間的比較……………………………11
表1-2　1984年到最近的p-type半導體的歷年最高載子移動率………12
表2-1　P3HT溶於二甲苯(Xylene)與甲苯(Toluene)之載子遷移率與
　　　　臨界電壓比較表…………………………………………………32
表3-1　OTFT元件連續量測之電性比較…………………………………52

圖目錄
圖1-1　常見有機半導體的化學結構………………………………………13
圖1-2　(a) Top-contact (b) Bottom-contact OFET剖面結構圖……………14
圖1-3　底部接觸電極與頂部接觸電極的FET元件………………………14
圖1-4　(a) 理想p型半導體MOS場效電晶體的能帶圖…………………15
圖1-4　(b) 施加於金屬電極的偏壓V < 0，Accumulation mode…………15
圖1-4　(c) 施加於金屬電極的偏壓V > 0，Depletion mode………………16
圖1-4　(d) 施加於金屬電極的偏壓V >> 0，Inversion mode……………16
圖1-5　(a) 有機薄膜電晶體的VGS < 0 ，而VS = VD = 0………………17
圖1-5　(b) 薄膜電晶體之間閘極電壓VGS < 0且汲極電壓VD < 0，
　　　　VS = 0………………………………………………………………17
圖1-5　(c) 閘極電壓VGS > 0，而VS = VD = 0…………………………18
圖1-6　典型OTFT之次臨界特性…………………………………………18
圖2-1　RR-P3HT化學結構…………………………………………………32
圖2-2　P3HT結晶結構示意圖……………………………………………33
圖2-3　一般聚塞吩衍生物的合成方法……………………………………34
圖2-4　PU結構化學式………………………………………………………35
圖2-5　電極與修飾層間孔洞之示意圖……………………………………35
圖2-6　改變PU塗佈轉速比較OTFT元件在VGS = -40 V時的VDS-ID
　　　　特性圖………………………………………………………………36
圖2-7　P3HT溶於Xylene或Toluene之VDS-ID比較圖………………………36
圖2-8　P3HT溶於Xylene或Toluene之VGS-ID比較圖………………………37
圖2-9　數位定量點膠機之正反面示意圖…………………………………38
圖2-10　PVD蒸鍍狀況示意圖………………………………………………39
圖2-11　PVD機台示意圖……………………………………………………40
圖2-12　為單層弱吸收之光譜圖，虛線為光譜之包絡線，假設n >ns……41
圖2-13　拉曼散射原理圖……………………………………………………41
圖2-14　P3HT分子鍵結與振動模式的拉曼圖譜…………………………42
圖2-15　半導體載子基本躍遷模型…………………………………………42
圖2-16　光激螢光實驗架構…………………………………………………43
圖3-1　做在可彎曲基板上的OTFT元件結構……………………………53
圖3-2　將OTFT元件彎曲量測……………………………………………53
圖3-3　玻璃基板與塑膠基板上的OTFT元件之 VDS - ID比較圖………54
圖3-4　玻璃基板與塑膠基板上的OTFT元件之 VGS - ID比較圖………54
圖3-5　使用分光光度計量測PU薄膜的波長對應穿透率圖………………55
圖3-6　塑膠基板上的OTFT元件之VDS - ID 電性圖……………………55
圖3-7　塑膠基板上的OTFT元件之VGS - 電性圖………………………56
圖3-8　塑膠基板上的OTFT元件之VGS - log(ID)電性圖…………………56
圖3-9　重複量測OTFT元件之VDS - ID電性圖……………………………57
圖3-10　OTFT元件向外彎曲之載子遷移率比較圖…………………………58
圖3-11　OTFT元件向外彎曲之VDS -ID 比較圖…………………………58
圖3-12　OTFT元件向外彎曲之臨界電壓比較圖……………………………59
圖3-13　OTFT元件向外彎曲之 VGS -ID 比較圖…………………………59
圖3-14　OTFT元件向內彎曲之載子遷移率比較圖…………………………60
圖3-15　OTFT元件向內彎曲之VDS -ID 比較圖……………………………60
圖3-16　OTFT元件向內彎曲之臨界電壓比較圖……………………………61
圖3-17　OTFT元件向內彎曲之 VGS -ID 比較圖…………………………61
圖3-18　OTFT元件在向內彎曲1cm下的VDS - ID 圖……………………62
圖3-19　OTFT元件在向外彎曲1cm下的VDS - ID 圖……………………62
圖3-20　彎曲OTFT元件之拉曼比較圖—平行偏振…………………………63
圖3-21　彎曲OTFT元件之拉曼比較圖—垂直偏振…………………………63
圖3-22　基板彎曲而PU當做緩衝層示意圖…………………………………64
圖3-23　OTFT基板逐漸向內彎曲做光激螢光量測比較圖…………………64
圖3-24　OTFT基板逐漸向外彎曲做光激螢光量測比較圖…………………65
圖3-25　OTFT基板彎曲做光激螢光激光激發光譜量測比較圖……………65

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