遲滯現象於雙極性有機薄膜電晶體中的抑制

Abstract

本論文利用pentacene與PTCDI-C8兩種有機半導體作為主動層，製作成雙層結構的雙極性有機薄膜電晶體。由於在大氣環境下受到水、氧的影響，使N型通道電性難以在SiO2介電層上呈現，但若將介電層改為有機高分子材料後，即能夠在大氣環境下呈現N型通道的電性。由於介電層上表面上可能含有氫氧根或其它電荷缺陷，造成電性上的遲滯現象，因此選用無氫氧根的高分子PVCN作為介電層可改善雙極性有機薄膜電晶體的遲滯現象。另外，經過電容特性曲線分析後，發現與傳統的單一極性點晶體不同，雙極性有機薄膜電晶體在正負閘極偏壓都會累積載子。最後將兩顆相同的雙極性有機薄膜電晶體串接作成反相器，發現其能夠操作在第一與第三象限，如此的雙極性反相器可以大量簡化複雜的電路設計。

Suppression of hysteresis in ambipolar organic thin-film transistors (OTFTs) made of pentacene / N,N'-Dioctyl-3,4,9,10-perylenedicarboximide (PTCDI-C8) heterojunction structure have been demonstrated. Under ambient conditions, the n-channel performance is easily affected by water and oxygen, the devices made on SiO2 surface only exhibited ambipolar properties in inert condition. However, using the hydroxyl-free polymers as the insulators, the devices could exhibit ambipolar characteristics under ambient condition. More importantly, we also observed that the hysteresis has been suppressed. Furthermore, from the capacitance-voltage measurements, we observed the ambipolar OTFTs accumulated holes and electrons under negative and positive voltages respectively. Finally, a CMOS-like inverter has been constructed by using tow identical ambipolar transistors. The inverter could operated in both the first and third quadrants, thereby simplifying the IC design. iv