Junction-temperature measurement in GaN ultraviolet light-emitting diodes using diode forward voltage method

A theoretical model for the dependence of the diode forward voltage (V-f) on junction temperature (T-j) is developed. An expression for dV(f)/dT is derived that takes into account all relevant contributions to the temperature dependence of the forward voltage including the intrinsic carrier concentration, the band-gap energy, and the effective density of states. Experimental results on the junction temperature of GaN ultraviolet light-emitting diodes are presented. Excellent agreement between the theoretical and experimental temperature coefficient of the forward voltage (dV(f)/dT) is found. A linear relation between the junction temperature and the forward voltage is found. (C) 2004 American Institute of Physics.