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Alternating-Current InGaN/GaN Tunnel Junction Nanowire White-Light Emitting Diodes

2015; American Chemical Society; Volume: 15; Issue: 10 Linguagem: Inglês

10.1021/acs.nanolett.5b02515

1530-6992

Sharif Md. Sadaf, Yong‐Ho Ra, Hieu Pham Trung Nguyen, Mehrdad Djavid, Zetian Mi,

Photocathodes and Microchannel Plates

The current LED lighting technology relies on the use of a driver to convert alternating current (AC) to low-voltage direct current (DC) power, a resistive p-GaN contact layer to inject positive charge carriers (holes) for blue light emission, and rare-earth doped phosphors to down-convert blue photons into green/red light, which have been identified as some of the major factors limiting the device efficiency, light quality, and cost. Here, we show that multiple-active region phosphor-free InGaN nanowire white LEDs connected through a polarization engineered tunnel junction can fundamentally address the afore-described challenges. Such a p-GaN contact-free LED offers the benefit of carrier regeneration, leading to enhanced light intensity and reduced efficiency droop. Moreover, through the monolithic integration of p-GaN up and p-GaN down nanowire LED structures on the same substrate, we have demonstrated, for the first time, AC operated LEDs on a Si platform, which can operate efficiently in both polarities (positive and negative) of applied voltage.