Study of InGaN/GaN LEDs on sub-Micron Spacing Patterned Sapphire Substrate

• Main Authors: Shih-Kuang Hsiao, 蕭世匡
• Other Authors: Edward Yi Chang
• Format: Others
• Language: en_US
• Published: 2008
• Online Access: http://ndltd.ncl.edu.tw/handle/39547088795507890281

碩士 === 國立交通大學 === 材料科學與工程系所 === 97 === 475-nm InGaN/GaN light-emitting diode (LED) structure successfully grown and fabricated on high density patterned sapphire substrate (PSS). Sub-micron fine pattern and inclined facet 45° pillar ideal for PSS was achieved using thermally reflow technique. GaN grown on such substrate has good crystalline quality, as observed from HRXRD. The full width at half maximum (FWHM) of the (102) plane rocking curve for GaN grown on flat sapphire substrate and PSS are 540 and 280 arcsec, respectively. Such improvement is thought to be due to the elimination of the threading dislocation density. For 350×350 µm2 PSS LED operating at the forward current of 20mA under room temperature, the forward voltage of 3.8V, the light emitting intensity is found to be 96.6mcd. Compared with the LED on the flat substrate, there was a drastic enhancement on brightness. This improvement could be attributed to the better quality of the material and increase of the light extraction by the inclined facet of the pillar pattern.