Li Hongjian, Li Panpan, Zhang Haojun, Chow Yi Chao, Wong Matthew S, Pinna Sergio, Klamkin Jonathan, Speck James S, Nakamura Shuji, DenBaars Steven P
Opt Express. 2020 Apr 27;28(9):13569-13575. doi: 10.1364/OE.384139.
We demonstrate a simple method to fabricate efficient, electrically driven, polarized, and phosphor-free white semipolar (20-21) InGaN light-emitting diodes (LEDs) by adopting a top blue quantum well (QW) and a bottom yellow QW directly grown on (20-21) semipolar bulk GaN substrate. At an injection current of 20 mA, the fabricated 0.1 mm size regular LEDs show an output power of 0.9 mW tested on wafer without any backside roughing, a forward voltage of 3.1 V and two emission peaks located at 427 and 560 nm. A high polarization ratio of 0.40 was measured in the semipolar monolithic white LEDs, making them promising candidates for backlighting sources in liquid crystal displays (LCDs). Furthermore, a 3dB modulation bandwidth of 410 MHz in visible light communication (VLC) was obtained in the micro-size LEDs (µLEDs) with a size of 20×20 µm and 40×40 µm, which could overcome the limitation of slow frequency response of yellow phosphor in commercial white LEDs combing blue LEDs and yellow phosphor.
我们展示了一种简单的方法，通过采用直接生长在（20-21）半极性块状GaN衬底上的顶部蓝色量子阱（QW）和底部黄色量子阱，来制造高效、电驱动、偏振且无磷的白色半极性（20-21）InGaN发光二极管（LED）。在20 mA的注入电流下，制造的0.1 mm尺寸的常规LED在未进行任何背面粗化处理的晶圆上测试时，显示出0.9 mW的输出功率、3.1 V的正向电压以及位于427和560 nm处的两个发射峰。在半极性单片白色LED中测得的偏振比高达0.40，这使其成为液晶显示器（LCD）背光源的有前途的候选者。此外，在尺寸为2×20 µm和40×40 µm的微型LED（µLED）中，在可见光通信（VLC）中获得了410 MHz的3dB调制带宽，这可以克服商用白色LED（结合蓝色LED和黄色磷光体）中黄色磷光体频率响应缓慢的限制。
