The role of zinc pre-exposure in low-defect ZnSe growth on As-stabilized GaAs (001)

Zinc coverage and the structures of Zn-exposed As-stabilized $\mathrm{GaAs}\text{(001)-(2×4)}$ and -$\text{c(4×4)}$ surfaces have been studied using x-ray photoelectron spectroscopy and scanning tunneling microscopy in order to clarify the role of the Zn pre-exposure process in ZnSe growth on GaAs(001). Since Zn atoms stick on the $\mathrm{GaAs}\text{-(2×4)}$ surface even though their interaction is very weak, Zn may act as a balancer to form a neutral ZnSe/GaAs interface. Zn can also remove excess As atoms and make a “pure” $\text{(2×4)}$ structure that is the only possible starting surface for low-defect ZnSe heteroexpitaxy on a GaAs(001) surface.