本論文主要探討由Pentacene/PTCDI-C13H27形成的異質型結構(p-n heterojunction)對有機N型記憶體元件之電特性與記憶效應的影響，利用P型半導體五苯環素(Pentacene)成長於N型半導體十三烷基駢苯衍生物(N,N′-ditridecylperylene-3,4,9,10- tetracarboxylic diimide, PTCDI-C13H27)上，製作出異質型結構的薄膜，並使用聚亞醯胺(Polyimide, PI)作為載子捕捉層材料，在此異質型結構上再透過物理氣相沉積製程製作15 nm厚的PTCDI-C13H27與80 nm厚銀電極，完成頂接觸式有機N型記憶體元件的製備。
經由TEM與AFM的分析結果顯示，當Pentacene厚度為2 nm~5 nm時，結晶形貌呈現出散佈狀的三維島嶼結構(island type)；當Pentacene厚度為10nm時，成長出傳統的樹突狀晶格結構，顯示在初期成長時，Pentacene分子的堆疊排列行為受到底層PTCDI-C13H27的影響，而有特殊的成長機制，而材料結晶度與晶格平面相關參數透過2D GI XRD來分析，當Pentacene分子在2 nm~5 nm厚度下時，較傾向往垂直於基板方向堆疊，水平方向的分子擴散能力較差，使得薄膜形成不連續性的結晶形貌；當Pentacene分子在8 nm~10 nm厚度時，橫向排列的有序度大幅提升，成長出連續性的晶格結構，且在厚度為10nm時，Pentacene薄膜具備高的結晶程度。
在電特性分析方面，當Pentacene的厚度在5nm時，記憶窗口有最大值48.9V，而在Pentacene的厚度為8 nm~10 nm時，記憶窗口卻逐漸下滑，此結果與異質結構薄膜分析結果相符，表示不連續的Pentacene結晶晶格，能在記憶體元件的操作中，提供額外的電洞載子，使得記憶窗口得到一定的增益，若Pentacene薄膜晶格連續性佳，可使得電洞載子傳輸通道被建立，使得上層PTCDI-C13H27的電子難以注入到下層結構及PI材料中，導致記憶窗口下降，由電容電壓分析與輸出特性曲線也能驗證上述結果。在記憶持久力方面，由於異質型結構中電子電洞覆合行為難以被抑制，使得記憶持久力的表現不佳，然而在記憶體耐久力方面卻表現出不錯的結果，元件在100次連續操作後，Pentacene 5 nm厚度的記憶體元件仍維持40V以上的記憶窗口。實驗最後一部分利用雷射光輔助的方式嘗試進一步提升記憶體元件的記憶效應，結果顯示由於被捕捉之電子已能被足量的電洞所清除，使得在Pentacene厚度5~10 nm時，光輔助方式對於記憶效應提升的效果並不顯著，然而在厚度為2 nm時，由於Pentacene結晶晶粒較為分散且結晶度不佳，使得光生載子的效應較為明顯。本研究發現了Pentacene分子在PTCDI-C13H27上特殊的晶格成長行為，並成功利用此異質型結構提升記憶體元件的記憶窗口。

The relationship between the thickness of pentacene in p-n heterojuntions and the electrical performance of non-volatile organic transistor memories (NVOTMs) was investigated in this study. The pentacene layer was deposited onto a 2.5 nm-thick PTCDI–C13H27 film to construct a heterostructure. The thicknesses of discontinuous pentacene films were found in the range between 2 and 5 nm measured by using atomic force microscope, while the completely continuous pentacene layer was about 10 nm. An ambipolar behavior in the output characteristics was observed in the NOVM with the continuous pentacene layer. Only n-type output characteristic was obtained in the NOVMs with the discontinuous pentacene layers. These results show that the continuous pentacene layer can improve the transport of holes, whereas the discontinuous pentacene layer cannot produce sufficient holes within the conductive channel. The memory windows of all NOVMs with p-n heterojunctions were studied. Among all the devices, the NOVM embedded the 5 nm-thick pentacene layer within the PTCDI–C13H27 has the largest memory window. This significant performance could be attributed to the appearance of discontinuous pentacene layer, which can provide the minority, i.e. holes, to promote the erasing ability. On the contrary, the continuous pentacene layer screens the trapped electrons during the programming operation and reduces the injection of holes during the erasing operation, yielding a decrease of memory window. In summary, we demonstrated an effective method to control the memory window by inserting p-n-heterojunction structure at polyimide/PTCDI-C13H27 interface.

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