Park Min Joo, Kwon K W, Kim Y H, Park S H, Kwak Joon Seop
Department of Printed Electronics Engineering, Sunchon National University, Jeonnam 540-742, Korea.
J Nanosci Nanotechnol. 2011 May;11(5):4484-7. doi: 10.1166/jnn.2011.3703.
We have demonstrated that the light extraction efficiency of the InGaN based multi-quantum well light-emitting diodes (LEDs) can be improved by using a single die growth (SDG) method. The SDG was performed by patterning the n-GaN and sapphire substrate with a size of single chip (600 x 250 microm2) by using a laser scriber, followed by the regrowth of the n-GaN and LED structures on the laser patterned n-GaN. We fabricated lateral LED chips having the SDG structures (SDG-LEDs), in which the thickness of the regrown n-GaN was varied from 2 to 6 microm. For comparison, we also fabricated conventional LED chips without the SDG structures. The SDG-LEDs showed lower operating voltage when compared to the conventional LEDs. In addition, the output power of the SDG-LEDs was significantly higher than that of the conventional LEDs. From optical ray tracing simulations, the increase in the thickness and sidewall angle of the regrown n-GaN and LED structures may enhance photon escapes from the tilted facets of the regrown n-GaN, followed by the increase in light output power and extraction efficiency of the SDG-LEDs.
我们已经证明，通过使用单芯片生长（SDG）方法可以提高基于InGaN的多量子阱发光二极管（LED）的光提取效率。SDG是通过使用激光划片机对尺寸为单芯片（600×250微米²）的n-GaN和蓝宝石衬底进行图案化，然后在激光图案化的n-GaN上重新生长n-GaN和LED结构来实现的。我们制造了具有SDG结构的横向LED芯片（SDG-LED），其中重新生长的n-GaN的厚度在2到6微米之间变化。为了进行比较，我们还制造了没有SDG结构的传统LED芯片。与传统LED相比，SDG-LED显示出更低的工作电压。此外，SDG-LED的输出功率明显高于传统LED。通过光线追踪模拟，重新生长的n-GaN和LED结构的厚度和侧壁角度的增加可能会增强光子从重新生长的n-GaN的倾斜面逸出，进而提高SDG-LED的光输出功率和提取效率。
