This semiconductor-materials study varies substrate temperature and V/III flux ratio during molecular beam epitaxy to identify a stable vapor-liquid-solid window for homogeneous axial Bi incorporation up to 2.4% in GaAsBi wires, while probing carrier localization and thermal quenching.
Key findings
- Stable VLS growth produced homogeneous axial Bi up to 2.4%, while VS growth caused radial overgrowth and compositional averaging. Homogeneous wires reached about 0.2% internal quantum efficiency at 260 K and a slightly larger temperature-dependent band-gap shift than GaAs nanowires and bulk GaAsBi. Droplet-mediated axial heterostructures were feasible.
Why this matters globally
The quantified process window can aid III-V infrared optoelectronics and nanoscale band-structure engineering, but the reported IQE remains low and defect reduction and device integration are still needed.
Thai researcher contribution
Chulalongkorn, NANOTEC, and MTEC researchers combined epitaxial growth, nanoscale structural and compositional analysis, and optical characterization in a Thai structure-process-property collaboration.
Limitations to consider
Results concern specific MBE conditions and samples; wire-level homogeneity does not establish wafer-scale uniformity. An IQE near 0.2% is not device performance, and Arrhenius fits may not uniquely separate overlapping mechanisms.