Abstract
Nitride light-emitting diodes are a promising solution for efficient solid-state lighting, but their performance at high power is affected by the efficiency-droop problem. Previous experimental and theoretical work has identified Auger recombination, a three-particle nonradiative carrier recombination mechanism, as the likely cause of the droop. In this work, we use first-principles calculations to elucidate the dependence of the radiative and Auger recombination rates on temperature, carrier density and quantum-well confinement. Our calculated data for the temperature dependence of the recombination coefficients are in good agreement with experiment and provide further validation on the role of Auger recombination in the efficiency reduction. Polarization fields and phase-space filling negatively impact device efficiency because they increase the operating carrier density at a given current density and increase the fraction of carriers lost to Auger recombination.
Highlights
Auger recombination in nitride semiconductorsThe recombination rate of carriers in a single-quantum-well device is given by the so-called
Nitride light-emitting diodes are a promising solution for efficient solid-state lighting, but their performance at high power is affected by the efficiency-droop problem
Calculations by Hader et al [24] found that direct Auger recombination is too weak in nitride LEDs to account for the observed droop, a finding that was subsequently verified by other theoretical work [25]
Summary
The recombination rate of carriers in a single-quantum-well device is given by the so-called. An imaginary component with a value equal to 0.3 eV was added to the intermediate-state energies in the denominator of (5) in order to numerically handle singularities due to such resonant direct transitions The value of this broadening parameter does not affect the calculated phonon-assisted Auger recombination rates in the nitrides. Subsequent theoretical work by Bertazzi et al [34] found values much lower than our calculated results and argued that phonon-assisted Auger recombination in the nitrides may only be relevant in low-bang-gap alloys (yellow-green) These calculations include the electron–phonon interaction only as a lifetime-broadening mechanism that relaxes the energy conservation requirement in (4). Other effects such as lattice expansion or the temperature dependence of the band structure may play a secondary role but were not explicitly considered in our work
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Free) 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call
