Deformation potential dominated phonons in ZnS quantum dots

TL;DR

This paper reports on the dominance of deformation potential in phonon interactions within ZnS quantum dots, revealing unique multi-phonon processes and zone boundary phonons enabled by quantum confinement effects.

Contribution

It demonstrates the presence of deformation potential dominated Raman spectra and multi-phonon processes specific to quantum confined ZnS nanoclusters under off-resonance conditions.

Findings

Zone boundary phonons observed in Raman spectra.

Even order overtones of TO modes suggest two-phonon dominance.

Two-phonon TO modes with specific symmetries are demonstrated.

Abstract

Strong deformation potential (DP) dominated Raman spectra are reported for quantum confined cubic ZnS nanoclusters under off-resonance conditions allowed only in quantum dots. A flurry of zone boundary phonons is demonstrated in the scattering process. Transverse optic (TO) mode in the multi-phonon process shows only even order overtones suggesting the dominance of a two-phonon process (having large DP value in ZnS) and its integral multiples. Two-phonon TO modes corresponding to A1 and B2 symmetries are also demonstrated under off-resonance conditions which are allowed only in quantum dots.