Observation of Surface Temperature distribution of Light- Emitting Diodes Grown on Patterned Sapphire Substrate by Infrared Camera

• Main Authors: Han-Wen Hsu, 許瀚文
• Other Authors: Jung-Chieh, Su
• Format: Others
• Language: zh-TW
• Published: 2016
• Online Access: http://ndltd.ncl.edu.tw/handle/2cx867

碩士 === 國立臺灣科技大學 === 電子工程系 === 104 === This current crowding effect of light-emitting diode (LED) resulted from the defects in the epilayers or arrangement of electrodes, and caused higher current density in partial region of light emitting layer. Since higher current density not only means higher light output, but also cause temperature rising and cause localized heating. Besides, the increasing non-radiative combination rate of of electrons and holes in emission layer of LED, and the total internal reflection effect also enhanced the temperature rise. Due to the abovementioned effects, the resulting self-heating effect reduces lifetime of LED and even do damage to epilayer materials. Therefore, LED chip temperature measurement becomes more important. Because of the size of LED chips is very small, is difficult to measure temperature by using contact thermometer. In this thesis, the non-contact thermometer (infrared camera) was used to measure LED chip surface temperature. However, the knowledge of emissivity for each epilayer materials is required to test the real temperature of LED surface epilayer. A black electrical insulation tape was used as a reference black body and referred to measure emissivity of each LED epilayer materials. After emissivity calibrating, the surface temperature of LED chip was tested by applying the emissivity of epilayers. Then, the temperature measured by infarred camera was compared with the temperature calculated by forward voltage method.