Suppression of Auger-stimulated efficiency droop in nitride-based light emitting diodes

Abstract

We calculate the rate of nonradiative Auger recombination in InGaN/GaN quantum wells with rectangular and smooth confining potentials. The calculations show that the rate of Auger recombination in rectangular quantum wells is sufficiently high to explain the efficiency droop in nitride-based light emitting diodes (LEDs). This rate, however, can be reduced by softening of the confining potential and a three-fold suppression is demonstrated in the studied quantum wells. The suppression of the Auger recombination rate improves LED radiative efficiency and reduces the droop effect, as we show using the standard recombination (ABC) model.

Identification of nnp and npp Auger recombination as significant contributor to the efficiency droop in (GaIn)N quantum wells by visualization of hot carriers in photoluminescence

“…(3) Any asymmetry in the coefficients C nnp 6 ¼ C npp , for which various ratios are theoretically obtained, 11,24 leads to a further increase of the expected b beyond the theoretical lower limit 2.…”

Enabling area-selective potential-energy engineering in InGaN/GaN quantum wells by post-growth intermixing

“…3(d)]. The reduction of Auger recombination rate in potential profile softened QW was attributed to the suppression of large-momentum components of Fourier expansion in the wavefunctions of the bound carriers, as the integrals of these dominant components determines the probability of Auger recombination in III-nitride materials [34]. As a result, the efficiency droop in intermixed QW would be alleviated.…”

“…3(c), the strain distribution inside the InGaN QW was modified in intermixed QW, leading to the reduction in in-plane strain tensor in intermixed structure with Ld = 10 Å. Considering the quantum efficiency of InGaN QWs, the existing large nonradiative Auger recombination (RAuger) in conventional rectangular wells reduces the EL yield, and it is considered as the one of the causes of the efficiency droop [10,34]. Remarkably, the confining potentials in intermixed structure are smoothened, leading to a significant reduction in RAuger coefficient to 1/5 of its original value in intermixed structure at Ld = 10 Å [ Fig.…”

Effect of interface roughness on Auger recombination in semiconductor quantum wells

“…This discrepancy is most notable in III-nitride semiconductor alloys, [13][14][15][16][17][18][19][20][21][22][23][24][25][26][27][28] and complicates their advancement in important applications such as solid-state lighting and lasers. [29][30][31][32][33][34][35][36][37][38] It is now becoming clearer via experimental results that Auger recombination is present in III-nitrides, 14 and causes a detrimental decrease in radiative efficiency of light-emitting diodes (LEDs) operating at high operating current densities.…”

“…[2][3][4][5][6][7][8][9][10][11][12][13]21,22 However, in practice the roughness of this heterointerface is always present, in spite of advances in epitaxial crystal growth techniques such as molecular beam epitaxy (MBE) and metal organic chemical vapor deposition (MOCVD). 39,40 Specifically, for GaAs QWs with AlGaAs energy barrier layers the interface roughness is one to two monolayers (3-5 Å), 41 for InGaAs/InP QW/barriers it is one to four monolayers, 42 and InGaN/GaN QW/barriers it is one to six monolayers (3-18 Å).…”