Thermal resistanse and nonuniform distribution of electroluminescence and temperature in high-power AlGaInN light-emitting diodes

Abstract

Thermal resistanse and nonuniform distribution of electroluminescence and temperature in high-power AlGaInN light-emitting diodes, St. Petersburg Polytechnical

Effects of interfaces and current spreading on the thermal transport of micro-LEDs for kA-per-square-cm current injection levels

“…Many techniques have been developed to characterize the thermal properties of multilayer materials. 6,7,10,[19][20][21]24,[27][28][29][30][31][32] Micro-Raman spectroscopy provides a temporal, spectral and spatial resolution for thermal measurement. 27 The micron-class spatial resolution cannot satisfy the specic structure of an LED.…”

“…7 The electrical methods are also popularly used. 6,10,19,[29][30][31]34,35 The forward voltage (V f ) is sensitive to the junction temperature. 34,35 Aer the temperature coefficient K is measured, the junction temperature can be obtained in real time according to the voltage.…”

“…A transient thermal measurement based on the forward voltage method was developed to analyze multilayer LED package structures. 6,10,[29][30][31] The instrument of the transient thermal measurement is easy for a technician to operate even on a commercial LED. By analyzing the cumulative structure function and/or the differential structure function, different components of the LED packages can be recognized.…”

“… 9 The spreading thermal resistance will increase further with the increase of the injection level. 10 When the proximate μLEDs work together, such as the pixels in the high brightness micro-display, 11,12 the complexity of the lighting and the visible light communication (VLC), 1 the thermal transport will become more difficult, since the heating μLED will be surrounded by other heavily heating neighbors. In these cases, the design of current spreading, pixel size and geometry may be not effective to obtain the low junction temperature.…”