Raman Fingerprint of Pressure-Induced Phase Transitions in TiS3 Nanoribbons: Implications for Thermal Measurements under Extreme Stress Conditions

TL;DR

This study investigates pressure-induced phase transitions in TiS3 nanoribbons using Raman spectroscopy, revealing structural changes and thermal expansion properties crucial for nano-electronic applications under extreme stress.

Contribution

It provides the first detailed analysis of pressure-dependent Raman modes and phase transitions in TiS3 nanoribbons, including thermal expansion coefficient estimation.

Findings

Identification of four prominent Ag Raman bands under pressure.

Observation of a reversible structural transition around 13 GPa.

Complete structural phase transition at 43 GPa.

Abstract

Two-dimensional layered trichalcogenide materials have recently attracted the attention of the scientific community because of its robust mechanical, thermal properties and applications in opto and nanoelectronics devices. We report the pressure dependence of out-of plane Ag Raman modes in high quality few-layers titanium trisulfide (TiS3) nanoribbons grown using a direct solid-gas reaction method and infer their cross-plane thermal expansion coefficient.Both mechanical stability and thermal properties of the TiS3 nanoribbons are elucidated using phonon-spectrum analyses. Raman spectroscopic studies at high pressure (up to 34 GPa) using a diamond anvil cell identify four prominent Ag Raman bands; a band at 557 cm-1 softens under compression, and others at 175, 300, and 370 cm-1 show normal hardening. Anomalies in phonon mode frequencies and excessive broadening in line-width of the soft phonon about ~ 13 GPa are attributed to the possible onset of a reversible structural transition. A complete structural phase transition at 43 GPa is inferred from Ag soft mode frequency (557 cm-1) versus pressure extrapolation curve, consistent with recent reported theoretical predictions. Using the experimental mode Gr\"uneisen parameters i of Raman modes, the cross-plane thermal expansion coefficient Cv of the TiS3 nanoribbons at ambient phase is estimated to be1.32110-6K-1. The observed results are expected to be useful in calibration and performance of next generation nano-electronics and optical devices under extreme stress conditions.