Quantum Dot Color Conversion Efficiency Enhancement in Micro-Light-Emitting Diodes by Non-Radiative Energy Transfer

• Published in: IEEE electron device letters Vol. 42; no. 8; pp. 1184 - 1187
• Main Authors: Du, Zaifa, Li, Dianlun, Guo, Weiling, Xiong, Fangzhu, Tang, Penghao, Zhou, Xiongtu, Zhang, Yongai, Guo, Tailiang, Yan, Qun, Sun, Jie
• Format: Journal Article
• Language: English
• Published: New York IEEE 01-08-2021; The Institute of Electrical and Electronics Engineers, Inc. (IEEE)
• Subjects: <italic xmlns:ali="http://www.niso.org/schemas/ali/1.0/" xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance">μ LED; Color; color-conversion efficiency; Efficiency; Energy conversion efficiency; Energy transfer; Etching; Image color analysis; Light emitting diodes; Mesas; Microscopy; Nanolithography; non-radiative energy transfer; Quantum dots; Scanning electron microscopy; Semiconductor diodes; Spin coating
• ISSN: 0741-3106; 1558-0563
• DOI: 10.1109/LED.2021.3089580

The quantum dot (QD) color-conversion efficiency (CCE) in GaN micro-light-emitting diodes (<inline-formula> <tex-math notation="LaTeX">\mu </tex-math></inline-formula>LEDs) is greatly improved by non-radiative energy transfer (NRET) mechanism. An array of deep nano-holes with a diameter of about <inline-formula> <tex-math notation="LaTeX">1~\mu \text{m} </tex-math></inline-formula> was fabricated in <inline-formula> <tex-math notation="LaTeX">\mu </tex-math></inline-formula>LED mesas (<inline-formula> <tex-math notation="LaTeX">40\times 60\,\,\mu \text{m}^{2} </tex-math></inline-formula>) by nanoimprint lithography. The nano-holes were etched straight through the <inline-formula> <tex-math notation="LaTeX">\mu </tex-math></inline-formula>LED active region to ensure that the filled QDs were in extremely close contact with the active region. The absorption efficiency and emission efficiency of QDs are effectively improved by NRET, resulting in a superhigh CCE in QD-<inline-formula> <tex-math notation="LaTeX">\mu </tex-math></inline-formula>LED hybrid devices. Compared to <inline-formula> <tex-math notation="LaTeX">\mu </tex-math></inline-formula>LED devices with conventional spin-coated QDs, the CCE of novel nano-hole <inline-formula> <tex-math notation="LaTeX">\mu </tex-math></inline-formula>LEDs with filled QDs has been enhanced by about 118%.