QDev Seminar: Mikelis Marnauza, Lund University

GaSb nanowire growth revealed using in-situ Environmental TEM

Understanding how growth conditions affect the resulting III-V nanowire morphology, composition and properties is crucial to increase the usefulness of these materials in applications. However, conventional growth methods do not allow the real time investigation of the growth processes occurring at the nanoscale, which forces conclusions to instead rely on theoretical predictions and extrapolation from post growth analysis. In recent years, through development of specialized environmental transmission electron microscopes (ETEMs), we have been able to finally look inside this “black box” seeing the growth process in real time which has allowed to obtain first hand experimental data on nanowires during the steady state growth process.

In my talk I will showcase some of the recent results obtained from the ETEM at Lund University with the specific focus of our ongoing work in studying the growth of Au-seeded GaSb nanowires. By acquiring compositional data during growth, we demonstrate how the precursor flows affect the seed particle composition during growth. Furthermore, we observe that changes in the precursor flow affect the particle composition and can not only lead to dramatic changes in nanowire diameter but also drastic changes in the growth dynamics. Lastly, I will demonstrate preliminary results into our work in growth of GaSb-GaAs heterostructures through analysis real-time videos of the junction formation process.

Figure 1: (a) Au-seeded GaAs-GaSb nanowire heterostructure imaged during in-situ growth. (b-c) GaSb nanowires grown at different V/III ratios.