垂直式高分子金屬基極電晶體

Abstract

本論文旨在實現新穎有機電子元件並且探討其特性。本論文展示了高分子熱載子電晶體與高分子空間電荷限制電晶體這兩種垂直式高分子金屬基極電晶體，以及一種發光高分子空間電荷限制電晶體。首先將討論具有不同射極材料的高分子熱載子電晶體。當熱載子電晶體使用具有高能隙之高分子為射極材料時，共射電流增益為25。當元件使用具有低能隙之高分子為射極材料時，共射電流增益為31且輸出電流密度為31 mA/cm2。當元件的射極材料是混合有低能隙與高能隙的高分子時，電流密度可以達到428 mA/cm2。使用此電晶體去驅動高分子發光二極體時，可以達到3000 cd/m2的亮度。接著將討論高分子空間電荷限制電晶體的操作原理與特性。柵極上的孔洞大小與孔洞密度可以控制空間電荷限制電晶體的操作特性。在高真空下退火與增加絕緣層於柵極旁更可提升高分子空間電荷限制電晶體的特性。目前高分子空間電荷限制電晶體的最大輸出電流密度是27 mA/cm2，開關比為428，電流增益約為104。最後將討論由上發光高分子發光二極體垂直堆疊於高分子空間電荷限制電晶體所製成之發光高分子空間電荷限制電晶體。當柵極電壓調變於-0.9伏到0.9伏時，發光強度將可以被調變並且最亮可達1208 cd/m2。此發光高分子空間電荷限制電晶體的電流效率為10 cd/A。由於向上發出的光將不會被在下方的高分子金屬基極電晶體所阻擋，當電晶體與發光二極體面積相同時，基本上可以達到100 %的開口率。

This dissertation aims to realize and characterize novel organic electronic devices. Two vertical polymer metal-base transistors, namely polymer hot-carrier transistor and polymer space-charge-limited transistor, and one light-emitting polymer space-charge-limited transistor are demonstrated. First, polymer hot-carrier transistors with various emitter materials are discussed. For the metal-base hot-carrier transistor with high bandgap emitter, common-emitter current gain of 25 is obtained. For the metal-base hot-carrier transistor with low bandgap emitter, common-emitter current gain of 31 and the current density as high as 31 mA/cm2 are obtained. Furthermore, for the device using blend of high and low bandgap polymer as the emitter, the current density 428 mA/cm2 is achieved. The brightness of 3000 cd/m2 is obtained as a polymer light-emitting diode is driven by the hot-carrier transistor. Second, operation principles and electrical properties of the polymer space-charge-limited transistor are studied. The characteristics of the transistor can be tuned by the diameters and the density of the openings on the grid. Annealing in high vacuum as well as adding insulator on grid metal can further enhance the performance of the polymer space-charge-limited transistor. So far, output current density is about 27 mA/cm2, on/off ratio is 428, and current gain is around 104. Finally, a light-emitting polymer space-charge-limited transistor is realized by vertically stacking a top-emitting polymer light-emitting diode on a polymer space-charge-limited transistor. As the grid base voltage varies from −0.9 V to 0.9 V, the light emission is turned on and off with on luminance up to 1208 cd/m2. The current efficiency of the light-emitting transistor is 10 cd/A. The aperture ratio is basically 100 % because the light emitted upward is not shielded by the vertical metal-base transistor underneath with roughly the same area.