Soh C B, Wang B, Chua S J, Lin Vivian K X, Tan Rayson J N, Tripathy S
Institute of Materials Research and Engineering, A*STAR (Agency for Science, Technology and Research), 3 Research Link, 117602, Singapore.
Nanotechnology. 2008 Oct 8;19(40):405303. doi: 10.1088/0957-4484/19/40/405303. Epub 2008 Aug 20.
We report on the fabrication of a nano-cone structured p-GaN surface for enhanced light extraction from tunable wavelength light emitting diodes (LEDs). Prior to p-contact metallization, self-assembled colloidal particles are deposited and used as a mask for plasma etching to create nano-cone structures on the p-GaN layer of LEDs. A well-defined periodic nano-cone array, with an average cone diameter of 300 nm and height of 150 nm, is generated on the p-GaN surface. The photoluminescence emission intensity recorded from the regions with the nano-cone array is increased by two times as compared to LEDs without surface patterning. The light output power from the LEDs with surface nano-cones shows significantly higher electroluminescence intensity at an injection current of 70 mA. This is due to the internal multiple scattering of light from the nano-cone sidewalls. Furthermore, we have shown that with an incorporation of InGaN nanostructures in the quantum well, the wavelength of these surface-patterned LEDs can be tuned from 517 to 488 nm with an increase in the injection current. This methodology may serve as a practical approach to increase the light extraction efficiency from wavelength tunable LEDs.
我们报道了一种用于增强可调谐波长发光二极管（LED）光提取的纳米锥结构p-GaN表面的制备方法。在进行p接触金属化之前，先沉积自组装胶体颗粒，并将其用作等离子体蚀刻的掩膜，以在LED的p-GaN层上创建纳米锥结构。在p-GaN表面生成了一个定义明确的周期性纳米锥阵列，其平均锥直径为300 nm，高度为150 nm。与没有表面图案化的LED相比，从具有纳米锥阵列的区域记录的光致发光发射强度提高了两倍。具有表面纳米锥的LED在70 mA的注入电流下，其光输出功率显示出明显更高的电致发光强度。这是由于纳米锥侧壁对光的内部多次散射所致。此外，我们还表明，通过在量子阱中引入InGaN纳米结构，这些表面图案化LED的波长可以随着注入电流的增加从517 nm调谐到488 nm。这种方法可能是提高波长可调谐LED光提取效率的一种实用方法。
