气相生长与表征：半导体MoS2上的范德瓦尔斯BiSbTeSe薄片
Vapor phase growth and characterization of van der Waals BiSbTeSe platelets on semiconducting MoS2
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中文总结 AI 辅助
本研究报道了在半导体MoS2上直接气相生长范德瓦尔斯BiSbTeSe薄片，通过拉曼和能谱分析揭示了厚度相关的组成变化，为拓扑绝缘体异质结构提供了基础。
中文摘要 AI 辅助
三维拓扑绝缘体中的四方族材料，如BiSbTeSe（BSTS），因其具有补偿的、体绝缘的特性，在自旋电子学和量子器件应用中颇具吸引力。纳米结构的BSTS薄片有望用于基于拓扑绝缘体的实用器件。然而，它们的生长通常需要复杂的设备、有机金属前驱体或电绝缘衬底。在技术相关的半导体衬底上的简单生长在很大程度上仍未得到探索。在此，我们报道了使用预合成的BiSbTe1.5Se1.5晶体作为源材料，直接在半导体MoS2上气相生长范德瓦尔斯BSTS薄片。生长的BSTS薄片厚度范围为4纳米至246纳米，单个薄片的平均横向尺寸为1.4微米。结合原子力显微镜厚度测量获取的薄片拉曼光谱显示，光谱贡献来自BSTS和底层MoS2衬底。在特征BSTS模式中，A21g模式对薄片厚度和局部组成表现出最高的敏感性。能谱分析揭示了薄片组成对厚度的系统性依赖，在约49纳米处出现明显的交叉点，这与E2g拉曼带低波数分量的厚度依赖性变化相吻合。这种相关性表明拉曼行为具有与组成相关的起源，组成变化被初步归因于生长过程中各组成元素的挥发性差异。这些结果表明，MoS2是BSTS沉积的有前景的范德瓦尔斯平台，并为未来BSTS-MoS2异质结构的研究提供了结构和组成基线。
英文摘要
Three dimensional topological insulators of the tetradymite family, such as BiSbTeSe (BSTS), are attractive for spintronic and quantum device applications because of their compensated, bulk-insulating character. Nanostructured BSTS platelets are promising for practical TI based devices. However, their growth often requires complex equipment, organometallic precursors, or electrically insulating substrates. Simple growth on technologically relevant semiconducting substrates remains largely unexplored. Here, we report the vapor phase growth of van der Waals BSTS platelets directly on semiconducting MoS2 using a presynthesized BiSbTe1.5Se1.5 crystal as the source material. The grown BSTS platelets exhibit thicknesses ranging from 4 nm to 246 nm, with an average lateral size of 1.4 mkm for individual platelets. Raman spectra of platelets, acquired in correlation with AFM thickness measurements, reveal contributions from both BSTS and the underlying MoS2 substrate. Among the characteristic BSTS modes, A21g mode shows the highest sensitivity to platelet thickness and local composition. EDS analysis reveals a systematic thickness dependence of the platelet composition, with an apparent crossover around 49 nm that coincides with a change in the thickness dependence of the low-wavenumber component of the E2g Raman band. This correlation suggests a composition-related origin of the Raman behavior, with the compositional variations tentatively attributed to the differential volatility of the constituent elements during growth. These results demonstrate that MoS2 is a promising van der Waals platform for BSTS deposition and provide a structural and compositional baseline for future studies of BSTS-MoS2 heterostructures.
发表机构
- A.B. Nalbandyan Institute of Chemical Physics（A.B. 纳尔班扬化学物理研究所）
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