LED Lighting

Edit this paragraph LED lighting principle:
LED is Ⅲ - Ⅳ compound, such as GaAs (gallium arsenide), GaP (gallium phosphide), GaAsP (gallium arsenide phosphorus) and other semiconductor processing, and its core is PN junction. Therefore, it has the general characteristics of PN junction of the IN, ie the forward and reverse cut-off, breakdown characteristics. In addition, certain articles
Conditions, it also has light-emitting properties. In the forward voltage, electron injection from the P N Zone area, hole injection from the P area N area. Into other areas of the minority carriers (minority carriers) part of the carrier with the majority (more children) composite and light. Suppose P area in the light occurs, then the injected electrons and valence band holes recombine directly to light, or luminescence center was first captured, and then with the hole recombination. In addition to this light-emitting compound, but also some of the electrons are non-luminescent center (the center between the conduction band, medium band near the middle) to capture, and then with the hole recombination, the energy released each time is not, can not form a visible light. The amount of light relative to the composite light-emitting compound of the proportion of non-larger, higher quantum efficiency. Since minority carrier diffusion zone compound is light, so light only in the PN junction near the surface within a few μm generated. Theory and Practice shows that the peak wavelength λ of light emitting regions of semiconductor material with band gap Eg a photoelectric Orr
Off, that is???? λ ≈ 1240/Eg (mm) where Eg the unit electron volt (eV). If we can produce visible light (wavelength of 380nm ~ 780nm violet red), Eg of semiconductor materials should be between 3.26 ~ 1.63eV. Longer wavelength than the red light to infrared light. Now have infrared, red, yellow, green and blue LEDs, but the cost of Blu-ray diode, the price is high, use of non-universal.