Lee Chia-Yu, Tzou An-Jye, Lin Bing-Cheng, Lan Yu-Pin, Chiu Ching-Hsueh, Chi Gou-Chung, Chen Chi-Hsiang, Kuo Hao-Chung, Lin Ray-Ming, Chang Chun-Yen
Department of Photonics and Institute of Electro-Optical Engineering, National Chiao Tung University, Hsin-Chu 30010, Taiwan.
Department of Photonics and Institute of Electro-Optical Engineering, National Chiao Tung University, Hsin-Chu 30010, Taiwan ; Department of Electrophysics, National Chiao Tung University, Hsin-Chu 30010, Taiwan.
Nanoscale Res Lett. 2014 Sep 16;9(1):505. doi: 10.1186/1556-276X-9-505. eCollection 2014.
The flip chip ultraviolet light-emitting diodes (FC UV-LEDs) with a wavelength of 365 nm are developed with the ex situ reactive plasma deposited (RPD) AlN nucleation layer on patterned sapphire substrate (PSS) by an atmospheric pressure metal-organic chemical vapor deposition (AP MOCVD). The ex situ RPD AlN nucleation layer can significantly reduce dislocation density and thus improve the crystal quality of the GaN epitaxial layers. Utilizing high-resolution X-ray diffraction, the full width at half maximum of the rocking curve shows that the crystalline quality of the epitaxial layer with the (RPD) AlN nucleation layer is better than that with the low-temperature GaN (LT-GaN) nucleation layer. The threading dislocation density (TDD) is estimated by transmission electron microscopy (TEM), which shows the reduction from 6.8 × 10(7) cm(-2) to 2.6 × 10(7) cm(-2). Furthermore, the light output power (LOP) of the LEDs with the RPD AlN nucleation layer has been improved up to 30 % at a forward current of 350 mA compared to that of the LEDs grown on PSS with conventional LT-GaN nucleation layer.
通过常压金属有机化学气相沉积（AP MOCVD），在图案化蓝宝石衬底（PSS）上采用非原位反应等离子体沉积（RPD）AlN成核层，开发出了波长为365 nm的倒装芯片紫外发光二极管（FC UV-LEDs）。非原位RPD AlN成核层可显著降低位错密度，从而提高GaN外延层的晶体质量。利用高分辨率X射线衍射，摇摆曲线的半高宽表明，具有（RPD）AlN成核层的外延层的晶体质量优于具有低温GaN（LT-GaN）成核层的外延层。通过透射电子显微镜（TEM）估计位错密度（TDD），结果表明其从6.8×10^7 cm^(-2)降低到2.6×10^7 cm^(-2)。此外，与在具有传统LT-GaN成核层的PSS上生长的LED相比，具有RPD AlN成核层的LED在350 mA正向电流下的光输出功率（LOP）提高了30%。
