AlGaInP LED with surface structure of two-dimensional photonic crystal

Some progress in the research of GaN based LED with photonic crystal structure has been made recently. Based on the photonic crystal's photonic band gap effect and photon grating diffraction principle, the extraction efficiency of LED with photonic crystal can be improved. In this paper, the restriction on AlGaInP LED's extraction efficiency is analyzed, and the photonic crystal is introduced in to the AlGaInP LED to improve the extraction efficiency. The theoretical analyses and the experiment results show that the output luminous intensity of LED with photonic crystal is improved by 16%, which results from some effect of the GaN based LED with photonic crystal.

Tunnel Junction AlGaInP Light Emitting Diode

The n-type GaAs substrates are used and their conductive type is changed to p-type by tunnel junction for AlGaInP light emitting diodes (TJ-LED), then n-type GaP layer is used as current spreading layer. Because resistivity of the n-type GaP is lower than that of p-type, the effect of current spreading layer is enhanced and the light extraction efficiency is increased by the n-type GaP current spreading layer. For TJ-LED with 3μm n-type GaP current spreading layer, experimental results show that compared with conventional LED with p-type GaP current spreading layer, light output power is increased for 50% at 20mA and for 66.7% at 100mA.

LP-MOCVD制备AlGaInP高亮度橙横色发光二极管

利用LP-MOCVD外延生长AlGaInP DH 结构橙黄色发光二极管。引入厚层Al_(0.7)Ga_(0.3)As电流扩展层和Al_(0.5)Ga_(0.5)As-AlAs分布布拉格反射器(KBR)。20mA工作条件下，工作电压1.9V,发光波长峰值在605nm,峰值半宽为18.3nm,管芯平均亮度达到20mcd,最大29.4mcd,透明封装成视角(2θ_(1/2)15°的LED灯亮度达到1cd。

Coupled AlxGa1-xAs-AlAs distributed Bragg reflectors for high brightness AlGaInP light emitting diodes

A novel coupled distributed Bragg reflector (DBR) with double thickness periods was theoretically analyzed based on the spontaneous radiation properties of high brightness AlGaInP light emitting diodes(LED). Several important factors were considered including spontaneous radiation angle distribution, absorption and FTR of DBR. Calculation results showed that the optimum optical thickness of single layer of the DBR deviates from 1/4 lambda. AIGaInP high brightness light emitting diodes both with Al0.5Ga0.5As/AlAs coupled DBR and with conventional DBR were fabricated by metalorganic chemical vapor deposition(MOCVD). X-ray double crystal diffraction and reflection spectrum were employed to determine the thickness and reflectivity of the DBR. It was found that reflectivity of coupled DBR is less sensitive to incident angle than conventional DBR, higher external quantum efficiency of light emitting diodes with coupled DBR was obtained than that with conventional DBR.

High brightness AlGaInP orange light emitting diodes

Orange AlGaInP high brightness light emitting diodes (LEDs) were fabricated by low pressure metalorganic chemical vapor deposition(LP-MOCVD) technology. AlGaInP double heterojunction structure was used as active layer. 15 pairs of Al0.5Ga0.5As/AlAs distributed Bragg reflector and 7 mu m Al0.8Ga0.2As current spreading layer were employed to reduce the absorption of GaAs substrate and upper anode respectively. At 20mA the LEDs emitting wavelength was between 600-610nm with 18.3nm FWHM, 0.45mW radiation power and 1.7% external quantum efficiency. Brightness of the LED chips and LED lamps with 15 degrees viewing angle(2 theta(1/2)) reached 30mcd and 1000mcd respectively.

一种均匀准直LED光源系统的设计

设计了一种新型的采用LED作光源的仪器光源系统,使之符合一些光学仪器采用平行光照明、光束截面光强均匀的要求。运用波前重组的光波均匀方法，将LED光源发光整形为光强均匀的光斑;通过控制出射光线的高度,设计并优化准直光路。软件模拟和实际测量的结果表明,该光源系统出射光束发散角小于1.5度,指定区域内光强均匀度大于90%,光束准直度、均匀度都很高,并且结构简单紧凑,使仪器向小型化方向发展成为可能。

GaN基材料的生长及蓝光LED的研制

Submitted by zhangdi (zhangdi@red.semi.ac.cn) on 2009-04-13T11:45:31Z

高亮度AlGaInP发光二极管的研制

Submitted by zhangdi (zhangdi@red.semi.ac.cn) on 2009-04-13T11:45:31Z

新型结构LED大屏显示系统的研制

Submitted by zhangdi (zhangdi@red.semi.ac.cn) on 2009-04-13T11:45:31Z

立方相InGaN的生长及LED有源区的研究

Submitted by zhangdi (zhangdi@red.semi.ac.cn) on 2009-04-13T11:45:31Z

大功率650 nm 波段AlGaInP/GaInP 应变量子阱半导体激光器的研究

Submitted by zhangdi (zhangdi@red.semi.ac.cn) on 2009-04-13T11:45:31Z

GaN基UV-LED材料生长和特性研究

Submitted by zhangdi (zhangdi@red.semi.ac.cn) on 2009-04-13T11:45:31Z

GaN基LED发光效率提高方法研究

Submitted by zhangdi (zhangdi@red.semi.ac.cn) on 2009-04-13T11:45:31Z