Accurate determination of junction temperature in a GaN-based blue light-emitting diode using nonlinear voltage-temperature relation

Abstract

We investigate the junction temperature measurements for GaN-based blue light emitting diodes (LEDs) using nonlinear dependence of the forward voltage (V f ) on temperature. Unlike the conventional linear model of the dependence of V f on temperature, the modeling of the temperature dependent V f with a quadratic function showed good agreements with measured data in the temperature range between 20 and 100 o C. Using the proposed quadratic model, the junction temperature and thermal resistance of the measured LED could be accurately determined as the ambient temperature varied. It was observed that the junction temperature increment remained almost unchanged as the ambient temperature increased from 20 to 80 o C, which could be attributed to the interplay between the decrease in series resistance and the increase in non-radiative recombination with increasing temperature. The presented method for accurate determination of the junction temperature is expected to be advantageously employed for the thermal management of high-power LEDs.

Dynamic opto-electro-thermal characterization of solid state lighting devices: measuring the power conversion efficiency at high current densities

“…They stated that although the acceptor Mg in p-GaN material cannot ionize completely at-room temperature and the carrier density will change with temperature, this will not lead to a nonlinear relationship of T j -V f . Interestingly, a number of recent studies claim the non-linearity of T j -V f behavior for LEDs [32][33][34]. This is all while constant k values were reported in most of the previous FVM studies [27,28,35].…”

“…It can be seen that few pulses are performed and the value of 'n' rarely exceeds 10. This issue arises from the [36], Xi et al [37], Jiang et al [38], Keppens et al [27], Cheng et al [39], Liu et al [40], Kim and Han [41], Oh and Cho [42], Prinate et al [43], Lee et al [44], Tamdogan et al [45], Ozluk at al [46]., Zheng et al [47], and Onwukaeme et al [32]. Each colored line indicates the temperature difference between T p,1 and Tp,n.…”

Investigation of the Optimum Mg Doping Concentration in p-Type-Doped Layers of InGaN Blue Laser Diode Structures

“…Nevertheless, it would be meaningful to discuss the self-heating effect on the optimum doping concentration. In general, both the output power and forward voltage decrease as the temperature increases [48][49][50]. As shown in Figure 9, the output power and voltage also decreased with the increasing of the Mg doping concentration.…”

A Critical Review on the Junction Temperature Measurement of Light Emitting Diodes

“…In recent studies, it was claimed that the constant temperature coefficient voltage assumption for FVM is not always accurate. Onwukaeme et al [ 188 ] investigated the T j of GaN-based blue LEDs using the non-linear dependence of V f at temperature ranges of 20–100 °C. In their experiments, 100 mA pulses were used in the calibration process, and quadratic fitting was claimed to be more accurate than linear fitting for the temperature coefficient of voltage.…”

“…References from top to bottom are Xi et al [ 62 ], Xi et al [ 64 ], Jian et al [ 186 ], Keppens et al [ 184 ], Cheng et al [ 114 ], Liu et al [ 203 ], Kim and Han [ 190 ], Oh and Cho [ 196 ], Prinate et al [ 94 ], Lee et al [ 111 ], Tamdogan et al [ 164 ], Ozluk at al. [ 115 ], Zheng et al [ 145 ], and Onwukaeme et al [ 188 ]. Reprinted with permission from Ref.…”