Stoichiometry control and epitaxial growth of AgCrSe2 thin films by pulsed-laser deposition

TL;DR

This paper demonstrates the successful epitaxial growth of high-quality AgCrSe2 thin films using pulsed-laser deposition, enabling future exploration of its thermoelectric and spintronic properties at interfaces.

Contribution

It introduces a novel method for growing single-phase, epitaxial AgCrSe2 thin films with controlled stoichiometry via pulsed-laser deposition on lattice-matched substrates.

Findings

Achieved c-axis-oriented, single-phase AgCrSe2 thin films.

Confirmed epitaxial growth with twisted and polar domains.

Measured optical and magnetic properties consistent with bulk values.

Abstract

We report on epitaxial growth in thin-film synthesis of a polar magnetic semiconductor AgCrSe2 on lattice-matched yttria-stabilized zirconia (111) substrate by pulsed-layer deposition (PLD). By using Ag-rich PLD target to compensate for Ag deficiency in thin films, the nucleation of impurity phases is suppressed, resulting in the c-axis-oriented and single-phase AgCrSe2 thin film. Structural analysis using x-ray diffraction and cross-sectional scanning transmission electron microscopy reveals epitaxial growth with the presence of both twisted and polar domains. Optical absorbance spectrum and magnetization measurements show absorption edge at around 0.84 eV and magnetic transition temperature at 41 K, respectively. These values are consistent with the reported values of direct bandgap and N\'eel temperature of bulk AgCrSe2, reflecting a single-phase and stoichiometric feature of the obtained film. Our demonstration of epitaxial thin-film growth of AgCrSe2 serves as a bedrock for exploration of its potential thermoelectric and spintronic functionalities at surface or heterointerfaces.