Eur. Phys. J. B 79, 423-428 (2011)
https://doi.org/10.1140/epjb/e2011-10705-2

Long-wavelength, confined optical phonons in InAs nanowires probed by Raman spectroscopy

¹ IMEC, Kapeldreef 75, 3001 Leuven, Belgium
² Department of Physics and Astronomy, Katholieke Universiteit Leuven, Celestijnenlaan 200d, 3001 Leuven, Belgium
³ Department of Microbial and Molecular Systems, Katholieke Universiteit Leuven, Kasteelpark Arenberg 23, 3001 Leuven, Belgium
⁴ Department of Metallurgy and Materials Engineering, Katholieke Universiteit Leuven, Kasteelpark Arenberg 44, 3001 Leuven, Belgium
⁵ Department of Chemistry, Katholieke Universiteit Leuven, Celestijnenlaan 200f, 3001 Leuven, Belgium

Corresponding author: ^a cantoro@imec.be

Received: 14 September 2010
Revised: 6 January 2011
Published online: 1 February 2011

Abstract

Strongly confined nano-systems, such as one-dimensional nanowires, feature deviations in their structural, electronic and optical properties from the corresponding bulk. In this work, we investigate the behavior of long-wavelength, optical phonons in vertical arrays of InAs nanowires by Raman spectroscopy. We attribute the main changes in the spectral features to thermal anharmonicity, due to temperature effects, and rule out the contribution of quantum confinement and Fano resonances. We also observe the appearance of surface optical modes, whose details allow for a quantitative, independent estimation of the nanowire diameter. The results shed light onto the mechanisms of lineshape change in low-dimensional InAs nanostructures, and are useful to help tailoring their electronic and vibrational properties for novel functionalities.