In this work we study the optical properties of hydrogen-passivated, free-standing silicon and germanium nanowires, oriented along the [1 0 0], [1 1 0], [1 1 1] directions with diameters up to about 1.5 nm, using ab-initio techniques. In particular, we show how the electronic gap depends on wire’s size and orientation; such behaviour has been described in terms of quantum confinement and anisotropy effects, related to the quasi one-dimensionality of nanowires. The optical properties are analyzed taking into account different approximations: in particular, we show how the many-body effects, namely self-energy, local field and excitonic effects, strongly modify the single particle spectra. Further, we describe the differences in the optical spectra of silicon and germanium nanowires along the [1 0 0] direction, as due to the different band structures of the corresponding bulk compounds.

First-principles optical properties of silicon and germanium nanowires / M., Bruno; M., Palummo; Ossicini, Stefano; R., DEL SOLE. - In: SURFACE SCIENCE. - ISSN 0039-6028. - STAMPA. - 601:(2007), pp. 2707-2711. [10.1016/j.susc.2006.12.021]

First-principles optical properties of silicon and germanium nanowires

OSSICINI, Stefano;
2007

Abstract

In this work we study the optical properties of hydrogen-passivated, free-standing silicon and germanium nanowires, oriented along the [1 0 0], [1 1 0], [1 1 1] directions with diameters up to about 1.5 nm, using ab-initio techniques. In particular, we show how the electronic gap depends on wire’s size and orientation; such behaviour has been described in terms of quantum confinement and anisotropy effects, related to the quasi one-dimensionality of nanowires. The optical properties are analyzed taking into account different approximations: in particular, we show how the many-body effects, namely self-energy, local field and excitonic effects, strongly modify the single particle spectra. Further, we describe the differences in the optical spectra of silicon and germanium nanowires along the [1 0 0] direction, as due to the different band structures of the corresponding bulk compounds.
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First-principles optical properties of silicon and germanium nanowires / M., Bruno; M., Palummo; Ossicini, Stefano; R., DEL SOLE. - In: SURFACE SCIENCE. - ISSN 0039-6028. - STAMPA. - 601:(2007), pp. 2707-2711. [10.1016/j.susc.2006.12.021]
M., Bruno; M., Palummo; Ossicini, Stefano; R., DEL SOLE
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Utilizza questo identificativo per citare o creare un link a questo documento: https://hdl.handle.net/11380/459190
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