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

The quantum dot (QD) color-conversion efficiency (CCE) in GaN micro-light-emitting diodes ($\mu $ LEDs) is greatly improved by non-radiative energy transfer (NRET) mechanism. An array of deep nano-holes with a diameter of about $1~\mu \text{m}$ was fabricated in $\mu $ LED mesas ($40\times 60\,\,\mu \text{m}^{2}$) by nanoimprint lithography. The nano-holes were etched straight through the $\mu $ 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- $\mu $ LED hybrid devices. Compared to $\mu $ LED devices with conventional spin-coated QDs, the CCE of novel nano-hole $\mu $ LEDs with filled QDs has been enhanced by about 118%. [ABSTRACT FROM AUTHOR]