Inhomogeneous spectral broadening in deep ultraviolet light emitting diodes

摘要

We investigate the spectral broadening in deep ultraviolet (UV) multi quantum well light emitting diodes (LED)by modeling the emission spectra. Experimental emission spectra of deep UV LEDs exhibit a at tail towardslower energies and a steep decrease towards high energies that cannot be explained by convolution of the spectrumwith a broadening function. We devise a luminescence model based on the broadening of the density of states(DOS) function which is consistent with the experimental spectra. The broadening of the DOS also explainsthe emission red shift with respect to the quantum well subband transitions. In addition, we investigate theinuence of the DOS broadening on the carrier and luminescence in the active region.