Density Functional Study of Surface Passivation of Nonpolar Wurtzite CdSe Surfaces

The reconstructed geometries, surface energies, surfactant adsorption energies, and work function have been calculated for the nonpolar (101̅0) and (112̅0) surfaces of wurtzite CdSe. This study was undertaken in the framework of ab initio density functional theory. Passivation with an amine or phosphine group lowers the surface energy of both nonpolar surfaces. However, thiol passivation of (101̅0) increases its surface energy. Both (101̅0) and (112̅0) tend to maintain their bulklike structure more so when passivated. The surface work function of (101̅0) and (112̅0) decreased with amine and phosphine passivation; amine had a more marked effect. Thiol passivation, on the other hand, increased the work function of both surfaces studied.