Interface Effects on the Raman Spectra of Si/3C-SiC Superlattices
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Interface Effects on the Raman Spectra of Si/3C-SiC Superlattices E. F. Bezerra, A. G. Souza Filho, J. Mendes Filho, V. Lemos, and V. N. Freire Departamento de Física, Universidade Federal do Ceará, Centro de Ciências, Caixa Postal 6030, Campus do Pici, 60455-760 Fortaleza, Ceará, Brazil Y. Ikoma, F. Watanabe, and T. Motooka Department of Materials Science and Engineering, Kyushu University, Hakozaki, Fukuoka 812-8581, Japan ABSTRACT Theoretical calculations are performed on the role of smooth interfaces in the Raman spectra of Si/3C-SiC superlattices. The dispersion relations were obtained using a linear chain model with the alloyed interface δ-(3C-SiC)0.5(Si)0.5 described in the virtual crystal approximation. A modified bond-polarizability model was used to calculate the Raman spectra. The main results are the enhancement of the Raman spectra and the appearance of new peaks in between those related to the Si quasi confined and the 3C-SiC-confined modes with increasing number δ of interfacial monolayers (3C-SiC)0.5(Si)0.5. Some of the smooth interface related Raman peaks have intensity comparable with those of an abrupt Si/3C-SiC superlattice. INTRODUCTION Si/3C-SiC based heterostructures are very promising for the development of new semiconductors devices due either to the SiC properties as a large band gap material and the dominant role of silicon in the electronic industry [1]. In particular, Si/3C-SiC resonant tunneling diodes may be constructed by using very thin (
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