Kinetics and the crystallographic structure of bismuth during liquefaction and solidification on the insulating substrate

TL;DR

This study investigates the real-time kinetics and crystallographic structure of bismuth thin films during liquefaction and solidification on insulating substrates, revealing a two-step growth mechanism and controlled nanostructure formation.

Contribution

It demonstrates that pulsed laser deposition and molecular beam epitaxy enable precise control over bismuth nanostructure growth and orientation during phase transitions.

Findings

Instantaneous liquefaction and solidification observed.

Formation of (110)-oriented nanodots during phase transition.

PLD and MBE are effective for controlled bismuth nanostructure growth.

Abstract

Here we study the kinetics of liquefaction and solidification of thin bismuth films grown on the insulating substrate by the pulsed laser deposited (PLD) and molecular beam epitaxy (MBE) and investigated by in situ electron and X-ray diffraction. By PLD, we can grow films similar to those obtained using MBE, studied by ex-situ AFM, KPFM, XRR, and XRD. The liquefaction-solidification transition is monitored in real-time by RHEED and synchrotron XRD, resulting in a dewetting phenomenon and the formation of spherical droplets which size depends on the initial film thickness. Studying this phase transition in more detail, we find instantaneous liquefaction and solidification, resulting in formation of the nanodots oriented with a (110) crystallographic plane parallel to the substrate. Furthermore, we propose a two-step growth mechanism by analyzing the recorded specular diffraction rods. Overall, we show that the PLD and MBE can be used as a method for the highly controlled growth of Bi nanostructures, including their crystallographic orientation on the substrate.