The fabrication of GaN-based light emitting diodes (LEDs)

In this paper, we report on the fabrication of blue GaN based light emitting diodes (LEDs), and then on coating procedures to obtain white LED lamps from blue LED chips. Firstly, the multi-layers of nanometer thickness GaN are grown on quarters of 2-inch diameter (0001)-orientation (c-plane) sapphire substrates by using metal organic chemical vapor deposition (MOCVD) for a subsequent realization of the LED structures. Then, the blue GaN based LEDs are fabricated by using several standard microfabrication techniques, including mesa etching, metal deposition, lift-off and annealing. The luminous intensity of the fabricated blue LED chips, measured with a current of 20 mA, is approximately 80 millicandela (mcd). Afterward, a solution of phosphor (Y3Al5O12:Ce): epoxy is prepared to coat the blue LED chips, thus obtaining the white LED lamps. After the coating procedure, the power of the fabricated white LED lamps is about 40 lm W-1 at 20 mA current. All the obtained results have proved the success of the GaN-based LED fabrication and white LED lamps produced.

[1]  Y. Su,et al.  High-efficiency InGaN-GaN MQW green light-emitting diodes with CART and DBR structures , 2002 .

[2]  Y. Sung,et al.  Y3Al5O12:Ce0.05 phosphor coatings on a flexible substrate for use in white light-emitting diodes , 2004 .

[3]  W. Yong,et al.  Synthesis of Ce:YAG Phosphor via Homogeneous Precipitation under Microwave Irradiation , 2006 .

[4]  Jinn-Kong Sheu,et al.  Influence of Si-doping on the characteristics of InGaN-GaN multiple quantum-well blue light emitting diodes , 2002 .

[5]  Yu-Cheng Lin,et al.  High power nitride based light emitting diodes with Ni/ITO p-type contacts , 2003 .

[6]  W. Zhuang,et al.  A novel method for the synthesis of YAG:Ce phosphor , 2009 .

[7]  Fernando Ponce,et al.  High dislocation densities in high efficiency GaN‐based light‐emitting diodes , 1995 .

[8]  T. Wen,et al.  InGaN/GaN multiple quantum well green light-emitting diodes prepared by temperature ramping , 2003 .

[9]  Yan-Kuin Su,et al.  InGaN-GaN multiquantum-well blue and green light-emitting diodes , 2002 .

[10]  S. Nakamura,et al.  High-Brightness InGaN Blue, Green and Yellow Light-Emitting Diodes with Quantum Well Structures , 1995 .

[11]  T. Wen,et al.  InGaN/GaN tunnel-injection blue light-emitting diodes , 2002 .

[12]  S.J. Chang,et al.  White-light emission from InGaN-GaN multiquantum-well light-emitting diodes with Si and Zn codoped active well layer , 2002, IEEE Photonics Technology Letters.

[13]  A. Thompson.  MOCVD technology for semiconductors , 1997 .

[14]  Yan-Kuin Su,et al.  Nitride-based LEDs fabricated on patterned sapphire substrates , 2003 .

[15]  Yan-Kuin Su,et al.  InGaN/GaN light-emitting diodes with a reflector at the backside of sapphire substrates , 2003 .