Electronic structure of twinned ZnS nanowires

Abstract

The electronic properties of twinned ZnS nanowires (NWs) with different diameters were investigated based on first-principles calculations. The energy band structures, projected density of states and the spatial distributions of the bottom of conduction band and the top of the valence band were presented. The results show that the twinned nanowires exhibit a semiconducting character and the band gap decreases with increasing nanowire diameter due to quantum confinement effects. The valence band maximum and conduction band minimum originate mainly from the S-p and Zn-s orbitals at the core of the nanowires, respectively, which was confirmed by their spatial charge density distribution. We also found that no heterostructure is formed in the twinned ZnS NWs since the valence band maximum and conduction band minimum states are distributed along the NW axis uniformly. We suggest that the hexagonal (2H) stacking inside the cubic (3C) stacking has no effect on the electronic properties of thin ZnS NWs.

Intrinsic nanotwin effect on thermal boundary conductance in bulk and single-nanowire twinning superlattices

“…These so-called coherent twinning superlattices with lamellar twinning running either perpendicular or parallel to the growth direction have been observed in various types of semiconductor NWs [16], including Si and SiC materials [17][18][19][20][21][22]. Given their high atomic-scale order and symmetry, TBs are considered as near-perfect interfaces for their reduced phonon and electron scattering characteristics compared to general grain boundaries [23][24][25][26][27][28][29]. As such the electronic band energies can change sharply across a TB, since this type of interface is a flat, atomicallythin hexagonal layer between two diamond-cubic grains [18].…”

Growth and properties of coherent twinning superlattice nanowires

“…Past first-principles simulation studies have revealed that twin boundaries in NWs are somewhat transparent to electron transport. [43][44][45] However, Tsuzuki et al 43 have found that applying an external strain along the NW axis can significantly shift the bottom of the conduction band in the quantum barriers associated with twin boundaries, and that different electronic properties can rise by tuning both the applied strain and TBS in InP NWs. This phenomenon stems from inhomogeneous stress fields caused by twinning and surface faceting under an applied strain, which locally affects the conduction and valence band potentials.…”

Phase equilibrium of Cd 1– x Zn x S alloys studied by first-principles calculations and Monte Carlo simulations

“…Both CdS and ZnS are II-VI direct band gap semiconductors, and their band gaps are 2.40 eV and 3.65 eV, respectively. [1][2][3] The former is a typical material for the buffer layer of the high-efficiency CuIn 1−x Ga x Se 2 thin film solar cells. [4] However, cadmium, a kind of heavy metal toxic element, can do harm to the environment and human health.…”