Phosphor-Free InGaN White Light Emitting Diodes Using Flip-Chip Technology

Materials

Dan Zhou¹  Lee Chow²  Chia-Yi Yen³  Ke-Wei Pan³  Hou-Jen Chen³  Ying-Chang Li³  Liann-Be Chang³  Wen-Yu Kuo⁴  Bohr-Ran Huang⁴  Ewa Popko⁵ 

[1] Department of Materials Science and Engineering, University of Central Florida, Orlando, FL 32816, USA;Department of Physics, University of Central Florida, Orlando, FL 32816, USA;Graduate Institute of Electro-Optical Engineering, Chang Gung University, Taoyuan 333, Taiwan;Graduate Institute of Electro-Optical Engineering, National Taiwan University of Science and Technology, Taipei 10607, Taiwan;Institute of Physics, Wroclaw University of Technology, 50-370 Wroclaw, Poland;

关键词: InGaN/GaN;    quantum dot;    quantum well;    phosphor free;    white LED;   

DOI  :  10.3390/ma10040432

来源: DOAJ

【 摘 要 】

Monolithic phosphor-free two-color gallium nitride (GaN)-based white light emitting diodes (LED) have the potential to replace current phosphor-based GaN white LEDs due to their low cost and long life cycle. Unfortunately, the growth of high indium content indium gallium nitride (InGaN)/GaN quantum dot and reported LED’s color rendering index (CRI) are still problematic. Here, we use flip-chip technology to fabricate an upside down monolithic two-color phosphor-free LED with four grown layers of high indium quantum dots on top of the three grown layers of lower indium quantum wells separated by a GaN tunneling barrier layer. The photoluminescence (PL) and electroluminescence (EL) spectra of this white LED reveal a broad spectrum ranging from 475 to 675 nm which is close to an ideal white-light source. The corresponding color temperature and color rendering index (CRI) of the fabricated white LED, operated at 350, 500, and 750 mA, are comparable to that of the conventional phosphor-based LEDs. Insights of the epitaxial structure and the transport mechanism were revealed through the TEM and temperature dependent PL and EL measurements. Our results show true potential in the Epi-ready GaN white LEDs for future solid state lighting applications.

【 授权许可】

Unknown