| Summary: | 碩士 === 國立成功大學 === 光電科學與工程學系 === 104 === 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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