聚3-己基□吩空間電荷限制電晶體對偏壓不穩定性之研究

Abstract

由於有機電晶體具有低臨界電壓、製程簡單、可大面積製造、成本較低與可用溶液製程等許多優點，使其具有相當潛力，並可應用於許多電子產品上，像是可撓式顯示器的驅動元件、互補式電路、射頻辨識和生醫感測器等等，這些在近年來被廣泛地開發，然而運用於商品的過程中以及對元件更進一步了解上，我們需要知道元件的穩定性，因此在本研究中針對基於P3HT (Poly(3-Hexylthiophene))做為主動層材料的空間電荷限制電晶體(space-charge-limited transistor, SCLT)來探討其環境及偏壓穩定性。在文獻[1]中，以pentacene作為主動層且閘極經自組裝分子處理過的水平結構OTFT元件，其在低偏壓條件VGS為-3V，VDS為-2V時，經過3500秒的偏壓下臨界電壓偏移量□Vt約為-0.2V，而在我們的元件以P3HT作為主動層且基極經自主裝分子處理後，於低偏壓條件下VBE為-1V，VCE為-1.5V時，經過3500秒的偏壓下臨界電壓偏移量□Vt約為-0.07V，顯示我們的元件具有不錯的偏壓穩定性，而在環境穩定性方面若於一般環境下元件良好封裝的情況時，在7小時內其□Vt的絕對值約為0.008V，電流變化比小於0.3%。除了有自組裝分子的元件，我們也比較沒有自組裝分子的元件，並且比較不同偏壓操作情形下□Vt對時間的改變。

Because organic transistors possess many advantages like low threshold voltage, simple making, large-area manufacturing, low cost, solution-processed, which let it have potential to be used in many electronic products such as driving component of flexible display, complementary circuits, radio-frequency identification, biosensor and etc. All of above are widely developed, however if we want to more understand our device mechanism and let it be applied as commercial products, we should more realize the stability of our device. Therefore, in this thesis we discuss environment and bias instability in our space-charge-limited transistor (SCLT) based on P3HT (Poly(3-Hexylthiophene)) as active layer. In some reports [1], they research horizontal-structure OTFT. The active layer is pentacene and the gate is dealt with self-assembled molecular. For low bias condition, VGS is -3V and VDS is -2V after 3500 seconds bias time, the threshold voltage shift □Vt is approximate -0.2V. For our SCLT, the active layer is P3HT and base is dealt with self-assembled molecular. if we give it low bias condition, VGS is -1V and VDS is -1.5V after 3500 seconds bias time, the threshold voltage shift □Vt is approximate -0.07V. It implies that our vertical structure device also possesses good bias stability. About environment stability, if we well seal our device and store it in atmosphere, within 7 hours the absolute value of □Vt is less than 0.008V, and the current variation ratio is less than 0.3%. Besides we make device which is not dealt with self-assembled molecular. Furthermore, we give device different bias condition and see the change of □Vt versus time.