Northeastern University, and roma will ZnO ultraviolet LED power up to 100 mu W

Tohoku university and roma will ZnO ( Zinc oxide) Kind of uv LED luminous intensity increased to 100 mu W, for 10000 times that of the original products. The luminous intensity is about 1/10 of the InGaN and GaN uv LED, 'clear the way forward after GaN products' ( Atomic molecular material science at Northeastern University in higher institutions, kawasaki, yaws) 。 Manufacturing LED components when using the MBE ( Molecular beam epitaxy) Method, and developed without the use of free radical gas doping ( 掺杂) Method. In this way, 'is expected to adopt more mass production of MOCVD ( Organic metal vapor deposition) Method '( Kawasaki) 。 Target is used for LCD back light and light white leds. This is by Northeastern University, kawasaki, metal material research institute, Northeastern University, northeast university institute of material science and common research results with roma.

with the LED element excitation green phosphor, can get the green light.

the team made of LED components, with p type MgZnO with n type ZnO layer structure, formed on the conductive ZnO base plate. Luminescence center wavelength of 380 nm. With the LED components stimulate green phosphor, available for the center with 520 nm wavelength of green light. Although the luminous efficiency is less than 1%, but the estimate that 1016 cm - as long as the p-type MgZnO Hole concentration up to about 3 cm - 1018 About 3, can be made to improve the luminous efficiency digits '( Northeastern University, kawasaki) 。

the structure of the traditional ZnO LED components ( Left) With the element structure ( Right) 。

the team in 2004 by pulsed laser deposition ( PLD） Method, developed by the p-type ZnO with leds composed of n-type ZnO layer structure. The element LED the luminous intensity of components is lower than the 4 digits, luminescence center wavelength of 440 nm, belong to the blue area. The band gap ( Forbidden bandwidth) The bigger p type MgZnO instead of p-type ZnO. So the 'can prevent electrons from the n type into p-type ZnO MgZnO, so that the carrier in the n type recombine and shine in the ZnO layer. In this way, can support ZnO forbidden bandwidth uv light source '( Northeastern University, kawasaki) 。

uv LED luminous intensity of components.

according to introducing, the MBE method is used to form the LED components, mainly from two aspects of improvement, significantly improve the luminous intensity of LED. 1 point is to improve the MgZnO with ZnO layer interface quality, 2 points is for doping nitrogen in MgZnO layer ( N) And use the ammonia ( NH3） , so as to improve the hole concentration will exert beneficial effects on light. On the latter, and in order to MgZnO layer doped N with nitric oxide ( 没有) Compared to the base method, luminous intensity raised about two digits. According to introducing, even if you don't use free radicals gas, also can grow high quality crystals, so the future is expected to adopt more MOCVD method is suitable for mass production.

traditional element and the component of ZnO LED light-emitting spectral compare.

the research team, said using uv LED white leds, and the collocation with blue leds and yellow phosphor InGaN and GaN, compared to white leds is expected to improve the color and the color reproducibility. Manufacturing, in addition, the panel said, GaN class is difficult to purchase LED to high quality single crystal slab at a lower price, but can be easily synthesized ZnO class LED single-crystal base plate. Therefore, is expected to be at a low cost production adopts single crystal slab LED components, this bottom can make the light emitting layer with the mesh easily match.