| Summary: | 碩士 === 國立中央大學 === 光電科學研究所 === 98 === In this paper, the light pattern modulation is proposed for polymer (man-2403) micro-nano structures on transparent conductive layer in GaN light-emitting diodes (LEDs). By using the finite difference time domain (FDTD) method and E-beam lithography in the filling factor of 0.3 to discuss the influence of light pattern modulation.
Light pattern modulation of Type II , Type III and Type IV by using FDTD method. Type II : uniform light pattern within ±30° .Type III : maximum of two peak intensities at the angle = ±41°. Type IV : high directional light pattern within ±15°.
The point light source chosen for providing a good resolution for observing the light modulation caused by the polymer micro-nano structures.
The deviation of light pattern between the experimental and simulated results may result from the spatial intensity distribution resolution of Electroluminescence system and the surface roughness of transparent conductive layer.
At an injection current 20 mA, the polymer micro-nano structures on the conductive transparent layer results in an increase of optical output power by 5.97 %, 7.35 %, and 3.77 % for Type II, Type III and Type IV, respectively.
In electrical characteristics, the availability of polymer micro-nano structures made variation of forward bias voltage within 0.62 %. The damage of forward bias voltage was small.
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