Pawbake Amit S, Island Joshua O, Flores Eduardo, Ares Jose Ramon, Sanchez Carlos, Ferrer Isabel J, Jadkar Sandesh R, van der Zant Herre S J, Castellanos-Gomez Andres, Late Dattatray J
School of Energy Studies, Department of Physics, Savitribai Phule Pune University , Pune 411007, India.
Physical & Materials Chemistry Division, CSIR-National Chemical Laboratory , Dr. Homi Bhabha Road, Pune 411008, India.
ACS Appl Mater Interfaces. 2015 Nov 4;7(43):24185-90. doi: 10.1021/acsami.5b07492. Epub 2015 Oct 22.
Titanium trisulfide (TiS3) has recently attracted the interest of the 2D community because it presents a direct bandgap of ∼1.0 eV, shows remarkable photoresponse, and has a predicted carrier mobility up to 10000 cm(2) V(-1) s(-1). However, a study of the vibrational properties of TiS3, relevant to understanding the electron-phonon interaction that can be the main mechanism limiting the charge carrier mobility, is still lacking. In this work, we take the first steps to study the vibrational properties of TiS3 through temperature-dependent Raman spectroscopy measurements of TiS3 nanoribbons and nanosheets. Our investigation shows that all the Raman modes linearly soften (red shift) as the temperature increases from 88 to 570 K due to anharmonic vibrations of the lattice, which also includes contributions from the lattice thermal expansion. This softening with the temperature of the TiS3 modes is more pronounced than that observed in other 2D semiconductors, such as MoS2, MoSe2, WSe2, and black phosphorus (BP). This marked temperature dependence of the Raman spectra could be exploited to determine the temperature of TiS3 nanodevices by using Raman spectroscopy as a noninvasive and local thermal probe. Interestingly, the TiS3 nanosheets show a stronger temperature dependence of the Raman modes than the nanoribbons, which we attribute to lower interlayer coupling in the nanosheets.
三硫化钛（TiS3）最近引起了二维材料领域的关注，因为它具有约1.0 eV的直接带隙，表现出显著的光响应，并且预测的载流子迁移率高达10000 cm² V⁻¹ s⁻¹。然而，目前仍缺乏对TiS3振动特性的研究，而这对于理解可能是限制电荷载流子迁移率的主要机制的电子 - 声子相互作用至关重要。在这项工作中，我们通过对TiS3纳米带和纳米片进行与温度相关的拉曼光谱测量，首次对TiS3的振动特性展开研究。我们的研究表明，随着温度从88 K升高到570 K，由于晶格的非谐振动（其中也包括晶格热膨胀的贡献），所有拉曼模式都会线性软化（红移）。TiS3模式随温度的这种软化比在其他二维半导体（如MoS2、MoSe2、WSe2和黑磷（BP））中观察到的更为明显。拉曼光谱这种明显的温度依赖性可被利用，通过将拉曼光谱用作一种非侵入性的局部热探针来确定TiS3纳米器件的温度。有趣的是，TiS3纳米片的拉曼模式比纳米带表现出更强的温度依赖性，我们将其归因于纳米片中较低的层间耦合。
