Nitride Semiconductors has launched a portfolio of ultra-high power, ultra-violet LEDs delivering output powers that can be in excess of 3W.

The NS380L-6SVR, produces 3200mW at 380 nm. According to the company, the output of this LED at this wavelength exceeds all other commercial devices based on a single chip.

Nitride Semiconductors has also launched a range of longer wavelength cousins, such as the NS400L-6SVR, which delivers an output of 3200mW at 400nm.

The new range of chips combines an operating voltage of 4V with very high efficiencies. For example, driven at 800 mA, the NS380L-5SVR produces 700 mW at 380 nm, equating to an external quantum efficiency of 35 percent. Meanwhile, the 400 nm-emitting equivalent, the NS400L-5SVR, delivers an external quantum efficiency of 38.7 percent when driven at 1000 mA, and emitting 1200mW.

Nitride Semiconductors’ ultraviolet LEDs are 2.2 mm square - they are claimed to be the biggest on the market.

Scaling the size of the chip while maintaining its performance is not trivial. Although increases in the chip’s size boost output, efficiency is often compromised, due to heating issues and inferior current spreading within the device.

To address these issues, the engineers at Nitride Semiconductors produce their UV LEDs in a different way. They have developed a new layer structure to release the heat efficiently and introduced an electrode designed to flow current uniformly. This has been accomplished by minimising crystal defects through optimisation of epitaxial growth, and developing a vertical chip design with an optimal electrode pattern.

The large size of these devices enables the company to produce a single-chip ultraviolet LED with an output of several Watts; competing designs tend to be based on multiple chips.

According to the company, the benefits of a single chip design include simplification of optics and a low driving voltage - when multiple chips are used, they are connected in series.

Ultra-violet LEDs are packaged in a surface mounted device format, and available in three sizes, ranging from 4.2 mm square to 5.6 mm square. They are designed for good heat transmission, and because the thickness of package is only 1.3mm, they can be mounted in high density by reflow soldering.

The range of LEDs, which have been produced at a manufacturing cost that is just one tenth of that of the previous generation of devices, will be available for sampling from April 2013.

Reliability is quoted at 10,000 hours, and guaranteed for 1000 hours.