Manipulation of structural and optical behaviors in zincblende and wurtzite mercuric sulfide (HgS) nanocrystals: atomistic tight-binding theory

To obtain comprehensive information regarding the effect of size and geometric structure on the associated atomistic properties of mercuric sulfide (HgS) nanocrystals, the structural and optical properties of HgS semiconductor nanocrystals were explored numerically using atomistic tight-binding theory. The optical bandgap, charge density, density of states, electron–hole Coulomb energy, and optical spectrum were evaluated for different sizes and geometric structures. Size-dependent computations were realized by changing the diameter of the HgS nanocrystals. In addition, HgS nanocrystals with wurtzite and zincblende geometric structures were compared numerically. The theoretical results highlight that control of the electronic structure and optical properties of HgS nanocrystals can be achieved by changing their size and geometric structure. The dependence of the optical bandgap on the dimension of the HgS nanocrystals is mainly determined by quantum confinement. Finally, the optical properties of zincblende HgS nanocrystals are more promising than those of wurtzite HgS nanocrystals.