共振腔發光二極體(Resonant Cavity Light emitting Diodes, RCLED)是一種介於面射型雷射(Vertical Cavity Surface Emitting Laser, VCSEL)與發光二極體(Light-Emitting Diode, LED)之間的特別元件。相較於LED，RCLED有更好的方向性、光譜純度和溫度可靠性，也有更高的光萃取效率和調制帶寬。

為了形成共振腔，在 RCLED 的上、下介面，通常需要高反射率的分散式布拉格反射 (distributed Bragg reflector, DBR) 結構，才能在元件表面發出半高寬極窄(< 10 nm)的光訊號。目前與 RCLED 相關的文獻，多為可見光範圍的研究結果，紫外光 RCLED 由於磊晶、製成難度較高，相關文獻較少，電激發的紫外光 RCLED 就更少了。

本研究利用簡單的磊晶、製程步驟，在藍寶石基板上成長氮化鋁鎵 (AlGaN) 量子井，並利用空氣分別與氮化鎵(GaN)、藍寶石形成的介面，作為元件的共振腔，最後在磊晶片表面得到波長 340 nm 的RCLED。雖然操作電壓高達70 V，且光譜也出現明顯的缺陷光，但此種新式的 RCLED 結構，可大幅簡化磊晶、製程步驟，有潛力提升深紫外光LED的發光效率。

Resonant Cavity Light emitting Diodes (RCLED) can be regarded as the combination of Vertical Cavity Surface Emitting Laser (VCSEL) and Light-Emitting Diode (LED). It has the advantages of LED and VCSEL. Comparing with the typical LED, RCLED has higher power, efficiency and modulation bandwidth, as well as better directionality, spectral purity and temperature reliability. In order to form the resonant cavity, RCLED often requires highly reflective upper and bottom interfaces, like distributed Bragg reflector (DBR), to enable the surface emission peak with narrow full width at half maximum. Most of the relevant literatures focus on the research results of visible RCLEDs. The results on ultraviolet (UV) RCLEDs, particularly by electrical-pumping, are scarcely found because of the challenges in growth and fabrication.

In this study, we attained an electrical-pumping RCLED spectrum with the peaks centering at 340 nm, without resorting to the DBR interfaces. Although the spectrum comes with a high bias of 70 V and noticeable impurity emission, this unique UV RCLED greatly simplifies the growth/fabrication processes, benefiting the development of UV emitters.

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