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 ( μLEDs) is greatly improved by non-radiative energy transfer (NRET) mechanism. An array of deep nano-holes with a diameter of about 1 μm was fabricated in μLED mesas ( 40×60 μm²) by nanoimprint lithography. The nano-holes were etched straight through the μLED 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- μLED hybrid devices. Compared to μLED devices with conventional spin-coated QDs, the CCE of novel nano-hole μLEDs with filled QDs has been enhanced by about 118%.