Enhanced color-conversion efficiency between colloidal quantum dot-phosphors and nitride LEDs by using nano-patterned p-GaN
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We have demonstrated that color-conversion efficiency can be enhanced through the use of non-radiative energy transfer between CdSe/ZnS core/shell colloidal quantum dots(QDs) and nitride multi-quantum well(MQW) in light emitting diodes(LEDs) having nano-patterned p-GaN. The nitride LEDs having nano-patterned p-GaN were fabricated by selective deep etching of p-GaN by using self-assembled ITO nano-dots as a etch mask. For comparison, we also fabricated the nitride LEDs having groove-etched p-GaN as well as the LEDs having a normal p-GaN layer. The results show that the LEDs having nano-patterned p-GaN showed the higher color conversion efficiency of 15.5 % and the improved effective internal quantum efficiency of 71 %. The enhanced efficiency can be attributed to sufficient close QD-MQW separation due to deep etching of p-GaN by using nano-patterning, which resulted in faster energy transfer rate of 2.47 ns−1 for non-radiative QD-MQW energy-transfer.
KeywordsLight emitting diode Color-conversion efficiency Nano-patterning
This work was supported in part by the Industrial Technology Development Program funded by the Ministry of Knowledge Economy (MKE, Korea), by the National Research Foundation of Korea (NRF) grant funded by the Korea government (MEST) (No. 2011–0017325), and by BK21 PLUS at SCNU.
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