Title :
Control of the color contrast of a polychromatic light-emitting device with CdSe-ZnS nano-crystals on an InGaN-GaN quantum-well structure
Author :
Dong-Ming Yeh ; Chi-Feng Huang ; Horng-Shyang Chen ; Tsung-Yi Tang ; Chih-Feng Lu ; Yen-Cheng Lu ; Huang, J.-J. ; Yang, C.C. ; I-Shuo Liu ; Wei-Fang Su
Author_Institution :
Dept. of Electr. Eng., Nat. Taiwan Univ., Taipei
fDate :
3/1/2006 12:00:00 AM
Abstract :
Blue-red polychromatic light-emitting devices are fabricated by attaching red-emitting CdSe-ZnS nano-crystals on a blue-emitting InGaN-GaN multiple-quantum-well (MQW) structure. To improve the red/blue intensity contrast, holes of different diameters are fabricated for increasing the direct contact area between the MQW active regions and CdSe-ZnS nano-crystals. By comparing the devices of 10-, 50-, 60-, and 70-mum hole diameters, and a reference device of no hole, it is found that the hole diameter of 60 mum represents an optimized condition from the viewpoint of maintaining high quantum efficiency. However, the device of 10-mum holes has the highest red/blue intensity ratio, which corresponds to a 36% increase. This result is attributed to its largest side-wall area in the holes among various samples
Keywords :
cadmium compounds; colorimetry; colour; gallium compounds; indium compounds; light emitting diodes; nanostructured materials; optical fabrication; optical variables control; quantum well devices; zinc compounds; 10 to 70 mum; CdSe-ZnS; CdSe-ZnS nanocrystals; InGaN-GaN; InGaN-GaN quantum-well; color contrast; polychromatic light-emitting device; quantum efficiency; red/blue intensity ratio; Absorption; Costs; Fabrication; Joining processes; LED lamps; Light emitting diodes; Lighting control; Nanoscale devices; Phosphors; Quantum well devices; CdSe–ZnS nano-crystal; InGaN–GaN quantum well; light-emitting device; white light;
Journal_Title :
Photonics Technology Letters, IEEE
DOI :
10.1109/LPT.2006.870056
