alpha - HgS Nanocrystals: Synthesis, Structure and Optical Properties

TL;DR

This paper reports the synthesis of nearly spherical HgS nanocrystals, analyzes their structure and composition, and investigates their optical properties, highlighting quantum size effects and theoretical modeling of absorption spectra.

Contribution

It presents a wet chemical synthesis method for HgS nanocrystals and combines experimental characterization with theoretical modeling of optical absorption.

Findings

Nanocrystals are approximately 9 nm in size and in cinnabar phase.

Optical absorption shows blue-shifted excitonic peaks due to quantum confinement.

Theoretical model accurately simulates the absorption spectra considering size distribution.

Abstract

Well-separated mercury sulfide (HgS) nanocrystals are synthesized by a wet chemical route. Transmission electron microscopy studies show that nanocrystals are nearly spherical in shape with average size of 9 nm. Grazing angle X-ray diffraction confirms that HgS nanocrystals are in cinnabar phase. Particle induced X-ray emission and Rutherford back scattering spectrometry analysis reveal HgS nanocrystals are stoichiometric and free from foreign impurities. The optical absorption measurements show two excitonic peaks corresponding to electron-heavy hole and electron-light hole transitions, which are blue shifted by 0.1 and 0.2 eV, respectively, from its bulk value, due to quantum size effect. The experimental data obtained by optical absorption measurement is simulated with a theoretical model considering the particle size distribution as Gaussian.