Abstract

Epitaxial and polycrystalline films of iron (Fe), chromium (Cr), and calcium (Ca) silicides of various thicknesses (from 3.2 to 380 nm) were grown on silicon and sapphire substrates in ultrahigh vacuum by three methods (solid-phase epitaxy, reactive epitaxy and molecular beam epitaxy). The crystal structure and matching with the silicon lattice were determined for them using the X-ray diffraction method. A comparative analysis of Raman scattering spectra and far-IR spectroscopy spectra showed that films of semiconductor silicides have the strongest Raman peaks, and the detected shifts in their positions are caused by distortions in the silicide lattices. It has been established that in films of iron and chromium monosilicides at a fixed laser excitation wavelength ( \(\lambda=628.3\) nm) and a power of 3.4 mW, the strength of the Raman peaks decreases with decreasing film thickness and they disappear completely at a thickness below 10 nm. Chromium trisilicide films were grown on single-crystal sapphire, which made it possible for the first time to detect for it active Raman phonons at \(\lambda=488\) nm and a power of 0.42 mW at wave numbers 214.3 and 273.1 cm \({}^{-1}\) . The studied films of transition metal monosilicides are of significant interest from the perspective of their possible use as materials for thermoelectronics and spintronics, and systematized information on active Raman phonons and IR active phonons will make it possible to quickly determine the type of phase formed immediately after film growth.

中文翻译：

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硅和蓝宝石上的 Fe、Cr 和 Ca 硅化物薄膜中的光拉曼散射

摘要

通过三种方法（固相外延、反应外延和分子束外延）。使用X射线衍射方法确定了它们的晶体结构和与硅晶格的匹配。拉曼散射光谱和远红外光谱的对比分析表明，半导体硅化物薄膜具有最强的拉曼峰，检测到的拉曼峰位置偏移是由硅化物晶格的畸变引起的。已经确定，在固定激光激发波长（\(\lambda=628.3\) nm）和功率 3.4 mW 的铁和铬单硅化物薄膜中，拉曼峰的强度随着薄膜厚度的减小而降低，并且消失厚度完全低于10 nm。在单晶蓝宝石上生长三硅化铬薄膜，这使得首次能够在\(\lambda=488\) nm处检测到其活跃拉曼声子，在波数214.3和273.1 cm \处的功率为0.42 mW \ ({}^{-1}\)。从其可能用作热电子学和自旋电子学材料的角度来看，所研究的过渡金属单硅化物薄膜具有重大意义，并且有关活性拉曼声子和红外活性声子的系统化信息将使得快速确定在过渡金属单硅化物薄膜之后立即形成的相类型成为可能。薄膜生长。