V. Schwegler et al., Ohmic heating of InGaN LEDs during operation: Determination of the junction temperature and its influence on device performance, PHYS ST S-A, 176(1), 1999, pp. 783-786
Heat:generated by ohmic losses is a critical parameter for performance and
lifetime of light-emitting diodes (LEDs). The temperature of InGaN MQW LEDs
during operation has been investigated depending on the forward current us
ing three independent methods. First, the temperature of the active region
was derived from the electroluminescence spectra of the devices. Second, te
mperature dependent micro-Raman scattering by phonons was used to determine
,the local temperature. Finally a finite element simulation was performed t
o get a full temperature profile of the device. While the first method yiel
ds the temperature of the active region, the latter two can map the thermal
distribution. All three independent methods reveal maximum operation tempe
ratures about 120 to 130 degrees C at a forward current of 30 mA, correspon
ding to a power density of 705 W cm(-2).