First-principles calculations of the vibrational properties of bulk CdSe and CdSe nanowires

TL;DR

This paper uses first-principles calculations to study the vibrational and electronic properties of bulk CdSe and nanowires, revealing size-dependent vibrational modes and surface effects on the band gap.

Contribution

It provides detailed first-principles analysis of CdSe nanowires' vibrational properties and their dependence on size and surface termination, which was not previously comprehensively studied.

Findings

Vibrational modes are strongly size-dependent.

Surface termination influences the band gap.

Calculated vibrational spectra agree with experimental Raman data.

Abstract

We present first-principles calculations on bulk CdSe and CdSe nanowires with diameters of up to 22 \AA. Density functional linear combination of atomic orbitals and plane wave calculations of the electronic and structural properties are presented and discussed. We use an iterative, symmetry-based method to relax the structures into the ground state. We find that the band gap depends on surface termination. Vibrational properties in the whole Brillouin zone of bulk CdSe and the zone-center vibrations of nanowires are calculated and analyzed. We find strongly size-dependent and nearly constant modes, depending on the displacement directions. A comparison with available experimental Raman data is be given.