Effect of Auger Electron–Hole Asymmetry on the Efficiency Droop in InGaN Quantum Well Light-Emitting Diodes

The effect of Auger electron–hole asymmetry on the efficiency droop in indium gallium nitride quantum well (InGaN-QW) light-emitting diodes (LEDs) is investigated through a new open boundary quantum solver based on variational principles: Open Boundary Quantum LED Simulator (OBQ-LEDsim). OBQ-LEDsim eliminates the need for forcing artificial boundary conditions in LED simulations and features explicit expression of wavefunction with high generality, enabling incorporation of wavefunction penetration into barriers, quantum-confined Stark effects, and excitonic effects. As such, the Auger recombination’s primary channel is found to be the
hhe
Auger recombination because holes are more localized than electrons in the quantum well. Varying the ratio of electron (
$\text{C}_{\mathrm {n}}$
) to hole (
$\text{C}_{\mathrm {p}}$
), Auger coefficient
$\text{C}_{\mathrm {n}}/\text{C}_{\mathrm {p}}$
, from 0 to
$\infty $
suppresses the
hhe
Auger recombination, resulting in 25% higher electron and hole sheet charge densities in the LED active layer. This increases carrier screening of the polarization-induced electric fields and weakens quantum-confined Stark effects. One observes a 75% increase in the electron and hole square wavefunction overlap and an 8 nm blueshift in the peak emission wavelength. As a result, the efficiency droop in an InGaN-QW LED is reduced by a factor of 2 when the
$\text{C}_{\mathrm {n}}/\text{C}_{\mathrm {p}}$
is increased from 0 to
$\infty $
, whereas the ambipolar Auger coefficient is overestimated by as much as 62% if the Auger electron–hole asymmetry is neglected (
$\text{C}_{\mathrm {n}}/\text{C}_{\mathrm {p}} \sim ~1$
).