Jao Yu-Ming, Huang Bo-Ming, Chang Ching, Lin Fang-Zhong, Lee Guan-Ying, Huang Chung-Ping, Kuo Hao-Chung, Shih Min-Hsiung, Lin Chien-Chung
Graduate Institute of Photonics and Optoelectronics, National Taiwan University, Taipei 10617, Taiwan.
Institute of Lighting and Energy Photonics, College of Photonics, National Yang Ming Chiao Tung University, Tainan City 71150, Taiwan.
Nanomaterials (Basel). 2024 May 27;14(11):938. doi: 10.3390/nano14110938.
A special micro LED whose light emitting area is laid out in a U-like shape is fabricated and integrated with colloidal quantum dots (CQDs). An inkjet-type machine directly dispenses the CQD layer to the central courtyard-like area of this U-shape micro LED. The blue photons emitted by the U-shape mesa with InGaN/GaN quantum wells can excite the CQDs at the central courtyard area and be converted into green or red ones. The U-shape micro LEDs are coated with AlO by an atomic layer deposition system and exhibit moderate external quantum efficiency (6.51% max.) and high surface recombination because of their long peripheries. Low-temperature measurement also confirms the recovery of the external quantum efficiency due to lower non-radiative recombination from the exposed surfaces. The color conversion efficiency brought by the CQD layer can be as high as 33.90%. A further continuous CQD aging test, which was evaluated by the strength of the CQD emission, under current densities of 100 A/cm and 200 A/cm injected into the micro LED, showed a lifetime extension of the unprotected CQD emission up to 1321 min in the U-shape device compared to a 39 min lifetime in the traditional case, where the same CQD layer was placed on the top surface of a squared LED.
制造了一种特殊的微型发光二极管(micro LED),其发光区域呈U形布局,并与胶体量子点(CQD)集成。一台喷墨式机器将CQD层直接分配到这种U形微型发光二极管的中央庭院状区域。具有InGaN/GaN量子阱的U形台面发射的蓝光光子可以激发中央庭院区域的CQD,并将其转换为绿光或红光。U形微型发光二极管通过原子层沉积系统涂覆AlO,由于其周边较长,表现出适度的外部量子效率(最高6.51%)和较高的表面复合率。低温测量也证实了由于暴露表面的非辐射复合较低,外部量子效率得以恢复。CQD层带来的颜色转换效率可高达33.90%。在注入微型发光二极管的电流密度为100 A/cm²和200 A/cm²的情况下,通过CQD发射强度评估的进一步连续CQD老化测试表明,与传统情况(相同的CQD层放置在方形发光二极管的顶表面,寿命为39分钟)相比,U形器件中未受保护的CQD发射寿命延长至1321分钟。