Size-controlled excitonic effects on electronic and optical properties of Sb2S3 nanowires

Abstract

In this work, the electronic and optical properties of one-dimensional (1D) Sb₂S₃ nanowires (NWs) with different sizes are investigated using first-principles calculations. The indirect–direct band transition of Sb₂S₃ NWs can be tuned effectively by the NW size and various uniaxial strains. In the Sb₂S₃ NWs, the quantum confinement effects result in wider bandgaps while the significantly enhanced electron–hole interaction that is expected to produce excitonic bound states generates a bandgap narrowing. The exciton binding energies for the Sb₂S₃ NWs are predicted by the effective masses of electrons and holes to lie in the range of 0–1 eV, which are larger than that of bulk Sb₂S₃, suggesting that excitons in Sb₂S₃ NWs may bind possible defects to promote luminescence. The size-controlled absorption edge blueshift and redshift of Sb₂S₃ NWs suggest that Sb₂S₃ NWs may be promising in the applications of nanoscale light emitting devices.