LED based reference for wavelength and relative intensity

Abstract

Relative emission spectra of LEDs depend on the junction temperature. The high-energy region of the emission spectrum can be modelled with the joint density of states and the Maxwell-Boltzmann distribution as a function of energy and junction temperature. It can be shown that the normalized emission spectra at different junction temperatures intersect at a unique energy value. Thus the wavelength and the relative intensity of the intersection point do not depend on the junction temperature of the LED. The invariant intersection energy exists for all LEDs manufactured using the elements from groups III-V. The wavelength determined by the intersection energy can be used as a temperature invariant wavelength and relative intensity reference in spectral measurements.