針對發生在三明治型有機半導體元件裡的電性過程， 以金屬電極和有機半導體之間所形成的高載子能障為基礎，並研究其載子電流注入的情形， 我們已經建立了一套完整的數值模型。以聚二氧乙基噻吩╱聚對苯乙烯磺酸poly (3,4-ethylenedioxythiophene)-poly(styrenesulfo- nate)(PEDOT:PSS)作為陽極和金屬做為陰極， 並在其間夾著高能隙的聚芴所做成的單層發光二極體為例， 理論模型的預測已能夠對實驗結果提出量化的詳細說明。 在有著0.8電子伏特能量能障的陽極介面, 其電荷注入主要是由因為能量失序因素，使得能態在能帶附近有更寬廣的分佈， 而電荷就在所造成的半導體的能隙間態之間跳耀傳輸， 形成所謂的跳躍是電流注入。 而在低電壓的歐米行為已經被驗證是由導電團所形成的金屬細絲所造成而非如在無機半導體一樣的外來背景摻雜。 而在有著低功函數陰極的雙極發光二極體元件跟單極電洞元件相比較, 也證實在陽極附近， 電子缺陷的存在會大量地增強因Fowler-Nordheim穿隧機制所形成的電洞的注入因此造成電洞載子和其電流的快速增加。 除了在巨觀的電流之外，在微觀的世界觀測中， 載子密度已在不同的溫度之下利用電致紅外發光來獨立探測並且其結果也跟模型相吻合. 此外, 我們發現載子移動率對溫度的關係也因高載子密度的影響而減小。

A comprehensive numerical model is established for the electrical processes in a sandwich organic semiconductor device with high carrier injection barrier. The model prediction agrees in quantitative details with the experiments where high bandgap polyfluorene between poly(3,4-ethylenedioxythiophene)-poly(styrenesulfo- nate)(PEDOT:PSS) anode and metal cathode is taken as the example. The charge injection at the anode interface with 0.8 eV energy is dominated by the hopping among the gap states of the semiconductor caused by disorder. The Ohmic behavior at low voltage is demonstrated to be not due to the background doping but the filaments formed by conductive clusters. In bipolar devices with low work function cathode it is shown that near the anode the electron traps significantly enhance hole injection through Fowler-Nordheim tunneling, resulting in rapid increase of the hole carrier and current in comparison with the hole-only devices. In addition to current, carrier density is independently probed by electroluminescence-induced infrared absorption at various temperature and agree well with the model. It is found that temperature dependence of the carrier mobility is reduced at high carrier density.

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