Impact of structural design and bismuth segregation on GaAsBi/GaAs quantum wells for near-infrared emitters: A numerical study

In this work, we perform 8-band k·p simulations using the nextnano software to evaluate how Bi composition, quantum well width, and barrier thickness influence the interband transition energy and electron–hole envelope function overlap in GaAsBi/GaAs single- and multiple-quantum-well structures.The results show that the optimization of Bi content, well width, or barrier thickness lead to the improved electron–hole overlap of up to approximately 10%, indicating enhanced radiative recombination efficiency. We additionally model Bi surface segregation using experimentally reported segregation probabilities and observe substantial modifications of the confinement potential, redshifts of 17–26 meV in the conduction band heavy-hole transition energy, and reductions of 5–7% in the electron–hole overlap. These effects arise from electron delocalization into Bi-enriched barriers. The study highlights that Bi segregation must be explicitly considered in the design of GaAsBi-based emitters and provides quantitative guidelines for achieving efficient and 1 µm wavelength-stable devices.