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Surface and size effects of Raman redshift of semiconductor nanomaterials
M. Singh, B M Taele, S. Lara, N J Matjelo, M Kao and S.K. Singhal

Size and shape-dependent properties play a vital role in optimizing the performance of semiconductor nanomaterials for various applications. The Raman red shift of these materials is influenced by the reduction in particle size due to phonon confinement and the corresponding changes in vibrational modes. In this study, we propose a simple and unified model to characterize the size- and shape-dependent Raman shift in low-dimensional semiconductor nanomaterials. The properties of these materials are significantly affected by their packing fraction and relaxation factor. To estimate the Raman red shift, we developed a theoretical model based on the relaxation factor and packing fraction for nanomaterials such as InP, Si, CdSe, CeO₂, and SnO₂. Our findings show that the Raman frequency decreases as the particle size diminishes. Moreover, the reported results align closely with existing experimental and computational data for spherical nanomaterials, thereby validating the proposed model.

Keywords: Cohesive energy, Raman frequency, nanomaterials, dangling bonds, packing factor