Strain effect on the electronic and optical properties of CdSe nanosheet

The electronic and optical properties of CdSe nanosheet under uniform strain are investigated using first-principles calculations. The band structure, density of states and optical spectra of CdSe nanosheet are calculated. The conduction bands are found to move towards the Fermi energy when strain changes from compressive to tensile. This leads to a decrease in the energy bandgap. Optical properties also show strong dependence on strain. The peaks of the dielectric function are mapped with corresponding electron transitions between the bands. All peaks experiences redshifts under increasing strain. This phenomenon is explained via the analysis on the band structures. Other optical properties including the index of refraction, the extinction coefficient, the reflectivity, the absorption coefficient, and the energy-loss function were also calculated to investigate the mechanism of optical transitions of CdSe nanosheet.