Self-assembled nanodisks in coaxial GaAs/GaAsBi/GaAs core-multishell nanowires.

Bin Zhang,Irina A Buyanova,Mattias Jansson,Yumiko Shimizu,Fumitaro Ishikawa,Weimin M Chen

doi:10.1039/d0nr05488g

Abstract

III-V semiconductor nanowires (NWs), such as those based on GaAs, are attractive for advanced optoelectronic and nanophotonic applications. The addition of Bi into GaAs offers a new avenue to enhance the near-infrared device performance and to add new functionalities, by utilizing the remarkable valence band structure and the giant bowing in the bandgap energy. Here, we report that alloying with Bi also induces the formation of optically-active self-assembled nanodisks caused by Bi segregation. They are located in the vicinity to the 112 corners of the GaAsBi shell and are restricted to twin planes. Furthermore, the Bi composition in the disks is found to correlate with their lateral thickness. The higher Bi composition in the disks with respect to the surrounding matrix provides a strong confinement for excitons along the NW axis, giving rise to narrow emission lines (<450 μeV) with the predominant emission polarization orthogonal to the NW axis. Our findings, therefore, open a new possibility to fabricate self-assembled quantum structures by combining advantages of dilute bismide alloys and lattice engineering in nanowires.

Highlights

Bin Zhang, a Mattias Jansson, a Yumiko Shimizu,b Weimin M
III–V semiconductor nanowires (NWs), such as those based on GaAs, are attractive for advanced optoelectronic and nanophotonic applications
Through detailed cross-sectional structural and compositional characterization, we show that the nanodisks are formed due to Bi segregation in twin planes near six 〈112〉 corners of the GaAsBi shell, which is likely driven by favorable strain relaxation

Summary

Introduction

Bin Zhang, a Mattias Jansson, a Yumiko Shimizu,b Weimin M. Nanoscale the formation of embedded nanostructures because of alloy phase segregation were commonly observed in ternary III–V NWs, including AlGaAs,[26,27,28,29,30] AlInP31 and GaAsP.[32,33] Such selfassembled nanostructures create an exciton confinement potential and, act as optically-active quantum disks and quantum dots.[26,28,34] This extends possible applications of the NW structures to e.g. future quantum information technologies.[35,36] The alloy fluctuations are known to be especially pronounced in highly-mismatched alloys (e.g. GaAsBi and GaNAs), strongly magnified due to the giant bowing in the bandgap energy.

Results

Conclusion