交流白光非晶碳氫薄膜發光二極體之光電特性改善

Improvement of Optoelectronic Characteristics of a-C:H Alternating-Current White Thin-film Light-Emitting Diodes

王子綱(Tzu-Kang Wang)

指導教授 ： 洪志旺

國立中央大學/資訊電機學院/電機工程學系/碩士(2007年)

摘要

本研究的主要目的是改善交流白光非晶質薄膜發光二極體的特性。先前的研究已成功地運用一層很薄的本質非晶碳氫做為發光層，且利用PECVD系統在位氫電漿處理發光層薄膜，提高薄膜中的氫含量並且修補其中懸鍵來提高元件發光效率。在本研究中，主要是藉由調整發光層的厚度及在外部電極與i-a-C:H層之間加入i-a-Ge:H, i-a-SiGe:H, i-a-Si:H, and i-a-SiC:H 層來降低外部電極與非晶矽半導體間的接面電阻。實驗結果顯示，不同的膜厚與結構會明顯地影響元件發光效率。同時，我們也對元件光電特性做一系列量測，包括發光亮度、發光頻譜以及交流頻率響應等等。量測結果顯示，固定頻率下，不同大小的電壓值幾乎不會改變元件發光波段，但是在固定的交流電壓下，隨著頻率的增加卻會導致發光頻譜出現紅移的現象，而且我們也發現當薄膜發光二極體被操作在特定頻率範圍時可有效提昇元件的發光亮度。

關鍵字

光電特性 ； 發光二極體 ； 非晶碳氫 ； 薄膜 ； 白光 ； 交流

並列摘要

The main purpose of this study is to improve the optoelectronic characteristics of the previously reported alternating-current (AC) white amorphous thin-film light-emitting diodes, which have been fabricated with i-a-C:H luminescent layer treated with in-situ H2-plasma. The device optoelectronic characteristics had been successfully improved with the adjustment of i-a-C:H luminescent layer thickness and the insertion of i-a-Ge:H, i-a-SiGe:H, i-a-Si:H, and i-a-SiC:H layers between the external electrode and i-a-C:H layer to lower the contact resistances between the external electrode and amorphous semiconductor. A series of measurements including device brightness, electroluminescence (EL) spectrum, and frequency response had been taken to investigate the device characteristics. The results showed that the peak wavelength of device EL spectrum was almost independent of the applied-voltage. However, the EL spectrum would be red-shifted with the increasing AC frequency.

並列關鍵字

optoelectronic characteristics ； light-emitting diodes ； alternating-current ； a-C:H ； white ； thin-film

參考文獻

[23] G. H. Chen, “Design and fabrication of alternating current a-SiC:H thin-film light-emitting diodes,”M. S. Thesis, NCU, Taiwan, R.O.C., 2005.

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