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 (10 (1) over bar0) and (11 (2) over bar0) 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 (10 (1) over bar0) increases its surface energy. Both (10 (1) over bar0) and (11 (2) over bar0) tend to maintain their bulklike structure more so when passivated. The surface work function of (10 (1) over bar0) and (11 (2) over bar0) 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.