A study was made of the growth and interface properties of the intimate Pb-ZnSe contact using soft X-ray photo-electron spectroscopy. Metal films were deposited on two different ZnSe (001) reconstructed surfaces at room temperature, and the affect of subsequent in situ annealing was monitored. The results suggest the absence of extensive Pb-ZnSe reaction and interdiffusion, although the appearance of extra components in overlayer and substrate emission peaks suggest the formation of Pb-Se bonds at the interface for both reconstructed ZnSe surfaces. However, the thickness of this Pb-Se interface layer was strongly dependent on the surface stoichiometry, and this governed the subsequent metal growth mode. On the Zn-rich c(2 x 2) surface, a highly clustered Pb film was formed, while for the Pb layer grown on the Se-rich (2 x 1) ZnSe (001) surface, the Pb-Se interlayer was more prominent and the Pb growth mode was less clustered. On annealing, the desorption temperature of the Pb layer was similar, although a stable Pb---Se terminated surface was only observed for the initially Se-rich (2 x 1) ZnSe surface. This Pb-Se phase was fully desorbed at 480C, leaving a disordered Zn-rich surface. The interface potential barrier was determined in each case from the substrate core level positions, and a small difference was consistently found between the two ZnSe surfaces. The barrier height for Pb was however significantly lower than for other inert metals on n-ZnSe.

Influence of Surface Reconstruction on Pb-ZnSe Interface Formation. D.Wolfframm, D.N.Gnoth, M.Evans, K.Prince, D.Westwood, D.A.Evans: Applied Surface Science, 1998, 123-124, 575-9