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

Abstract

A theoretical model for the dependence of the diode forward voltage (Vf) on junction temperature (Tj) is developed. An expression for dVf∕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 (dVf∕dT) is found. A linear relation between the junction temperature and the forward voltage is found.