Van der Waals Epitaxy of Pulsed Laser Deposited Antimony Thin Films on Lattice-matched and Amorphous Substrates

TL;DR

This study demonstrates scalable pulsed laser deposition of high-quality, textured antimony thin films on various substrates, highlighting the role of interface phases and seed layers in achieving epitaxy and smoothness for applications in memory and photonics.

Contribution

It introduces a reliable bottom-up method for growing high-quality antimony thin films on different substrates using pulsed laser deposition, with insights into interface engineering.

Findings

Successful growth of textured Sb thin films on lattice-matched and amorphous substrates.

Identification of an intermediate phase at the Sb$_2$Te$_3$-Sb interface crucial for epitaxy.

Production of smooth, uniform Sb films suitable for phase-change and optoelectronic applications.

Abstract

Monatomic antimony thin films have recently attracted attention for applications in phase change memory, nanophotonics, and 2D materials. Although some promising results have been reported, the true potential of Sb thin films is still hindered by the scalability issue and the lack of reliable bottom-up production. Here we demonstrate the growth of Sb thin films on a lattice-matching and amorphous substrates using pulsed laser deposition (PLD). C-axis out-of-plane textured Sb thin films were successfully deposited on Sb$_2$Te$_3$ and SiO$_2$\Si$_3$N$_4$ substrates. In the case of growth on Sb$_2$Te$_3$, we show that an intermediate phase is formed at the Sb$_2$Te$_3$-Sb interface playing a crucial role in forming a solid coupling and thus maintaining epitaxy leading to the production of high-quality Sb thin films. A 3 - 4 nm amorphous Sb seed layer was used to induce texture and suitable surface termination for the growth of Sb thin films on amorphous substrates. The deposition parameters were fine-tuned, and the growth was monitored in situ by a Reflective High Energy Electron Diffraction (RHEED). Scanning/Transmission Electron Microscopy (S/TEM) unveiled the local structure of produced films showing the formation of $\beta$-phase Sb thin films. Our results demonstrate the feasibility to produce very smooth high-quality antimony thin films with uniform coverage, from few layers to large thicknesses, using pulsed laser deposition. We believe the results of our work on scalable and controllable Sb growth have the potential to open up research on phase-change materials and optoelectronics research.