Electronic states and phonon properties of Ge{sub x}Si{sub 1−x} nanostructures

• Published in: Annals of physics 2015-07, Vol.358
• Main Authors: Zhao, P.Q., National Laboratory of Solid State Microstructures and Department of Physics, Nanjing University, Nanjing 210093, Liu, L.Z., Yang, Y.M., Wu, X.L., Department of Physics, NingBo University, NingBo 3153001
• Format: Article
• Language: English
• Subjects: CLASSICAL AND QUANTUM MECHANICS, GENERAL PHYSICS; CONDENSED MATTER PHYSICS, SUPERCONDUCTIVITY AND SUPERFLUIDITY; ELECTRONIC STRUCTURE; GERMANIUM ALLOYS; NANOSTRUCTURES; PHONONS; RAMAN EFFECT; RAMAN SPECTRA; SILICON ALLOYS
• ISSN: 0003-4916; 1096-035X
• DOI: 10.1016/J.AOP.2014.12.024

Ge{sub x}Si{sub 1−x} nanostructures that can be manipulated through size reduction, geometry variation, and alloying, are considered as one of the key developments for next generation technologies, due to their easy processing, unique properties, and compatibility with the existent silicon-based microelectronic industry. In this review, we have thoroughly discussed the major advances in electronic structures and phonon properties of Ge{sub x}Si{sub 1−x} nanocrystals (NCs). Experimental and theoretical characterization related to several main factors, for example, size, composition, strain, temperature, and interface and surface were presented with special emphasis in low-frequency Raman scattering. Current difficulties in explaining the Raman spectra are the assignment of the low-frequency modes because of the complexity of the environment around the NCs, thus different theoretical models are introduced in detail to deal with different properties of Ge{sub x}Si{sub 1−x} alloy NCs including Lamb’s theory, complex-frequency (CF) model, core–shell matrix (CMS) model and spatial coherence effect model. - Highlights: • Major advances in electronic structures and phonon properties of Ge{sub x}Si{sub 1−x} nanocrystals are discussed thoroughly. • Experimental and theoretical characterization related to size, composition, strain, temperature, and interface/surface are elucidated. • Low-frequency Raman spectra are specially described based on spatial coherence effect model.