Toshiba is showing the development of the near UV LED, the external quantum efficiency of 36%

Toshiba in the Nano Tech 2009 international nanotechnology comprehensive exhibition (February 2009 ~ 20, 2009, Tokyo Ming International Convention and Exhibition Center) on display for the next generation of lighting LED developed near ultraviolet LED. External quantum efficiency is high, reaching 36%. The luminous wavelength is 380nm. In order to improve the luminous efficiency, the defect of GaN crystal was restrained and the flatness was improved.

The company has improved the AlN buffer layer between the sapphire substrate and GaN crystal and the absorption of different lattice constants (lattice constant). After the AlN thin layer was fabricated on sapphire substrate, the two stage growth method of M unit AlN single crystal was made by using high temperature above 1300 DEG c". In this way, it is possible to inhibit the growth of GaN crystal defects on the AlN layer. In addition, the self developed technology is used to solve the problem that the AlN is thick and the thermal expansion coefficient of the sapphire substrate is different.

The near UV LED can be achieved by the combination of red (R), green (G), blue (B) phosphor, fluorescent lamps with almost the same 2800K color temperature, as well as the average color rendering index (Ra) more than 90 of the lighting effect.

Figure 1: Toshiba exhibits the development of near UV LED