在本論文研究中，我們提出一具有前瞻性的策略來探討利用免轉移基板技術將薄層石墨烯片直接成長於n型氧化鋅奈米柱/p型氮化鎵異質接面發光二極體(LED)以提升該元件紫外發光之特性。我們利用射頻磁控濺鍍系統將非晶碳與金屬鎳薄膜鍍在LED元件上，再經由快速熱退火處理形成薄層石墨烯片於元件表面。結果發現，在低溫退火階段(~攝氏400度)，非晶碳會擴散至金屬鎳的上面並形成碳化鎳；在高溫退火階段(攝氏800-1100度)，我們發現鎳會自動蒸發，亞穩態的碳化鎳逐漸地轉變為石墨烯。經由一系列測試我們發現在鎳/碳比為65奈米/5奈米、退火溫度為攝氏1100度以及升溫速率為每秒攝氏15度的條件下，該實驗有最佳化的條件；經由拉曼光譜量測在最佳化條件下的石墨烯I2D/IG訊號比為0.42。與對照組(無石墨烯)相比，我們提出的元件結構搭配薄層石墨烯片其導通電壓縮小了3倍，這意味著其片電阻有顯著的下降情形。在電致發光部分，由於大部分注入的載子會局限在氧化鋅奈米柱一側，隨著注入電流的增加，我們提出的元件結構其紫外發光亦跟著增加，其現象可歸因於量子侷限效應。根據上述結果充分說明了我們提出的元件結構對於未來高效率LED在紫外發光的發展具有相當的前瞻性。

In this study, a promising strategy for enhanced UV emissions through a growth of transfer-free graphene on the n-ZnO nanorods(NRs) /p-GaN heterojunction light-emitting diodes (LED) is described. Few graphene layers are directly formed atop the LED device by the post-RTA treatment on sputtered amorphous carbon (a-C) and nickel (Ni) layers. It was found that in the low-temperature annealing stage (~400℃), the a-C diffuses into the Ni top layer to form Ni3C, while in the high-temperature annealing stage (800-1100℃), the metastable Ni3C transforms gradually into graphene by autonomous evaporation of Ni. Under the optimized fabrication condition (Ni/C=65nm/5nm, RTA=1100 ℃ with a heating rate~15 ℃/s), the I2D/IG ratio of 0.42 by Raman spectrum was obtained. As compared with the reference LED without graphene atop, the turn-on voltage of proposed hybridized structure is decreased by about 3 times, implying a significant decrease in the sheet resistance of the proposed device. The UV emission of electroluminescence (EL) spectra of treatment LED increases with the increasing injection currents, mainly attributed to the quantum confinement effect because the most of injected carriers are confined within the ZnO NRs. It suggests that the proposed hybridized structure will pave the way for the development of high efficient LED in the UV emission regime.

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