Determination of Junction Temperature in InGaN.pdf

1450 IEEE JOURNAL OF QUANTUM ELECTRONICS, VOL. 46, NO. 10, OCTOBER 2010 Determination of Junction Temperature in InGaN and AlGaInP Light-Emitting Diodes Ya-Ju Lee, Chia-Jung Lee, and Chih-Hao Chen Abstract —The junction temperature of a light-emitting diode important. Although there are many different approaches to (LED) directly and greatly affects its performances. Therefore, measure junction temperature [13]–[15], the physical depen- the reliable measurement and accurate estimation of the junction dence of junction temperature on injected currents was rarely temperature of an LED is extremely important. This paper proposes an approach for directly determining the dependence of discussed. In this paper, a series of temperature-dependent junction temperature on injected currents in InGaN and AlGaInP electrical and optical measurements of InGaN and AlGaInP LEDs. Various important physical parameters that affect the LEDs are made to estimate their junction temperatures. The junction temperature of an LED are also considered. theoretical derivation and possible determinants of the physical Index Terms—Junction temperature, light-emitting diode dependence of the junction temperature of an LED on the (LED), thermal resistance. injected current are also analyzed and discussed. I. Introduction II. Theoretical Model -V-BASED light-emitting diodes (LEDs) are of cur- IIIrent technological interest owing to t