Studies on the Enhancement inthe Electrical Characteristics ofPoly(3-hexylthiophene)Organic Thin Film Transistorby Surface Treatment

• Main Authors: Shao-Hsin Lin, 林少鑫
• Other Authors: Chin-Tsou Kuo
• Format: Others
• Language: zh-TW
• Published: 2008
• Online Access: http://ndltd.ncl.edu.tw/handle/31315010452504909118

碩士 === 大同大學 === 化學工程學系(所) === 96 === The characteristics of organic thin-film transistors (OTFTs) fabricated with highly regioregular poly(3-hexylthiophene) (P3HT) as semiconducting layer have been investigated. It is found that the electrical characteristics of P3HT OTFT fabricated with both SiO2 insulator and gold electrode treated with self-assembled monolayer (SAM) can be improved significantly The charge transport mobility and on/off current ratio of P3HT OTFT with SiO2 insulator modified with 1,1,1,3,3,3-hexamethyldisilazane (HMDS) by vacuum evaporating method are about one order of magnitude larger than those of device with untreated SiO2. It is found that the carrier transport mobility of OTFT increases with decreasing surface energy, which is due to the surface treatment of insulator. The HMDS treated-SiO2 insulator not only can be changed Si-OH to S-OR to reduce trapping center, but also improve crystalline order of P3HT thin film deposited. On the other hand, the charge transport mobility of P3HT OTFT for gold electrodes modified with three kinds of organic thiols: 1-octadecanethiol (1-ODT)、thiolphenol (TP) and 4-nirothiophenol (4-NTP), respectively, can be increased one order of magnitude larger than those of device with untreated SiO2. It is found that the subthreshold slope can be enhanced significantly. The charge transport mobility, on/off current ratio, threshold voltage, and subthreshold slope of P3HT OTFT with 4-NTP treated gold electrodes are 4.03 x 10-2 cm2/Vs，3.27 x 103，2.32 V and 1.60 V/decade, respectively. Furthermore, the charge transport mobility, on/off current ratio, threshold voltage, and subthreshold slope of P3HT OTFT fabricated by combing capping both gold electrode with 4-NTP and SiO2 with HMDS are 9.54 x 10-2 cm2/ Vs, 6.68 ×104, 2.73 V and 1.92 V/decade (under ambient conditions) and 2.13 x 10-1 cm2/ Vs, 1.15 × 105, -1.47 V and 1.40 V/decade (under partial vacuum of 3.7 x 10-2 torr), respectively.