Enhanced TE-polarized emission of AlGaN-based deep-ultraviolet light emitting diodes by using an InAlN insertion layer

The optical properties of Al0.44Ga0.56N/Al0.59Ga0.41N multiple quantum well structures with an InxAl1-xN insertion layer between the barrier layer and the well layer are investigated by using the effective mass theory. The numerical results show the TE-dominated emission can be realized by using the InxAl1-xN insertion layer, which can be mainly attributed to the larger separation of the electron-hole wave-function for the TM-dominated transition. Note that the rearrangement of valence subbands is also an important factor to enhance the TE polarization emission for the InxAl1-xN insertion layer with the lower In-content. The ratios of TE-polarized total spontaneous emission rate between the InxAl1-xN insertion layer structures (x = 0.11, 0.13, 0.15) and the conventional structure can reach 1.76-2.05 in the current density range of 2-300 A cm(-2) due to the larger product of Fermi-Dirac distribution functions of electron and hole. Furthermore, the InxAl1-xN insertion layer structures with x = 0.15-0.17 show the largest TE polarization emission. (C) 2019 The Japan Society of Applied Physics