LED grown on semi-polar GaN emits green and yellow colors

LED grown on semi-polar GaN emits green and yellow colors

Technology News |
By eeNews Europe

The LEDs were grown on an overgrown semipolar (11-22) GaN on micro-rod array templates, which were fabricated on GaN grown on m-plane sapphire.

Compared to commercial LEDs grown on the c-Plane, the research team’s green LEDs grown on the semipolar material showed reduced blue-shift in the emission wavelength with increasing driving current. The same observations were made in blue-shifts for the yellow-green and yellow LEDs, which the researchers noted suggested an effective suppression in quantum confined Star effect in their LEDs.

Electroluminescence emission photos of (a) green, (b) yellow-green, (c) yellow, and (d) amber LEDs, taken at 5, 20, and 100mA. (Photo courtesy of Applied Physics Letter)

On-wafer measurements yielded a linear increase in the light output with the current, and external quantum efficiency demonstrated a significant improvement in the efficiency-droop compared to commercial c-plane LED. Electro-luminescence polarization measurements showed a polarization ratio of about 25% in the semipolar LEDs.

The researchers claim the preliminary results suggest that the overgrowth technology is a potentially cost-effective approach to achieving semipolar GaN emitters with high performance in a long wavelength region.

A full report of the research study is published in Applied Physics Letter.

Related articles and links:

News articles:

Novel LED technology collaboration tackles green gap challenge

Osram research claims to reduce LED green gap phenomenon

Super Yellow blends boost the light efficiency of PLEDs

If you enjoyed this article, you will like the following ones: don't miss them by subscribing to :    eeNews on Google News


Linked Articles