Quantum efficiency of III-Nitride emitters: evidence for defect-assisted non-radiative recombination and its effect on the green gap

Abstract

Carrier lifetime measurements reveal that, contrary to common expectations, the high-current non-radiative recombination (droop) in III-Nitride light emitters is comprised of two contributions which scale with the cube of the carrier density: an intrinsic recombination --most likely standard Auger scattering-- and an extrinsic recombination which is proportional to the density of point defects. This second droop mechanism, which hasn't previously been observed, is likely caused by an impurity-assisted Auger process. Further, it is shown that longer-wavelength emitters suffer from higher point defect recombinations, in turn causing an increase in the extrinsic droop process. It is proposed that this effect leads to the green gap, and that point defect reduction is a strategy to both vanquish the green gap and more generally improve quantum efficiency at high current.

Second version: minor edits and figure updates, to match version published in Phys. Rev. Applied

References in corpus (6)

• Direct Measurement of Auger Electrons Emitted from a Semiconductor Light-Emitting Diode under Electrical Injection: Identification of the Dominant Mechanism for Efficiency Droop
• Unraveling the "Green Gap" problem: The role of random alloy fluctuations in InGaN/GaN light emitting diodes
• Atomistic analysis of the impact of alloy and well-width fluctuations on the electronic and optical properties of InGaN/GaN quantum wells
• First-principles calculations of indirect Auger recombination in nitride semiconductors
• Impact of carrier localization on recombination in InGaN quantum wells and the efficiency of nitride light-emitting diodes: insights from theory and numerical simulations
• Field-assisted Shockley-Read-Hall recombinations in III-Nitride quantum wells

Cited by in corpus (3)

• Polar InGaN/GaN quantum wells: Revisiting the impact of carrier localization on the green gap problem
• Observation of long-range carrier diffusion in InGaN quantum wells, and implications from fundamentals to devices
• Origin of the injection-dependent emission blueshift and linewidth broadening of III-nitride light-emitting diodes