金屬奈米粒子製作緩衝層應用於有機薄膜電晶體元件特性探討

Effects Of Metallic-Nanoparticle Buffer Layer On Characteristics Of Organic Thin Film Transistors

洪玉娟(Hong, Yujuan)

指導教授 ： 何正榮 ； 許佳振

國立中正大學/工學院/光機電整合工程研究所/碩士(2012年)

摘要

本文旨在探討金屬奈米粒子（Metallic nanoparticles）對有機薄膜電晶體(Organic thin-film transistors, OTFTs)元件性能之影響。本研究所使用的金屬奈米粒子為表面帶負電之金屬奈米粒子，有金與銀兩種，其中，金奈米粒子之粒徑有11奈米與33奈米兩種，而銀奈米粒子之粒徑為11奈米。此金屬奈米粒子層放置於SiO2介電層與P3HT半導體層之間作為緩衝層(Buffer layer)。結果顯示，由於表面負電特性可在介電層上形成負電荷的金屬奈米粒子緩衝層，增強介電層電場效應，吸引更多載子，提升元件飽和電流。因此塗佈適量的金屬奈米粒子作為緩衝層是可明顯提升元件之載子遷移率(Mobility)、輸出飽和電流、開關電流比(on/off ratio)等特性，而且起始電壓(VT) 也可以降低。 比較兩種粒徑相近的金奈米粒子與銀奈米粒子之緩衝層差異，顯示銀奈米粒子所降低之起始電壓量其實比起金奈米粒子相對低些，這是因為銀奈米粒子表面負電強度低使整體元件電場增加較低，因此，起始電壓降低相對來的少。但銀奈米粒子仍可以有效地提升介電層之介電常數，因介電常數與電容值成正比，所以有銀奈米粒子緩衝層之元件其電容值提升有助於輸出飽和電流提升進而提升元件之開關電流比與載子遷移率。

關鍵字

P3HT、金屬奈米粒子、有機薄膜電晶體

並列摘要

This study aims to investigate the effects of surface, negatively charged metallic nanoparticles (NPs), as a buffer layer and residing between the SiO2 dielectric layer and the P3HT semiconducting layer, on the performance of organic thin-film trnasistors (OTFTs). The two studied nanoparticles were gold nanoparticles (Au-NPs) and silver nanoparticles (Ag-NPs) and the sizes for Au-NPs were 33 nm and 11 nm in diamerter, respectively, while the diameter of Ag-NPs were around 11 nm. Both the influence of the particle size and the particle type were investigated. Resutls show that, due to the negative surface charge, the existence of the metallic NPs buffer layer was able to enhance the strength of the electric field which led to attract more hole carriers at the dielectric-semiconduting layer interface and ehanance the saturation source-drain current. Consquently, the device’s characteristics, including the mobility, on/off raito, and threshold volotage, were effecitvely improved. Comparing with the Au-NPs buffer-layered OTFTs, the threshold voltage of the Ag-NPs buffer-layered device was higher. This was due to the intensity of the negative charge of the Ag-NPs was smaller than that of the Au-NPs, the induced electric field strength by the Ag-NPs was thus poorer than that by the Au-NPs. However, the Ag-NPs buffuer layer can still effectively enhance the dielectric constant of the dielectric layer that caused an increase of capacitance and gave rise to better device characteristics.

並列關鍵字

P3HT、Metallic-Nanoparticle、Organic Thin Film Transistor

參考文獻

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