Temperature-dependent growth of the Na/GaP(110) interface

The adsorption of Na onto GaP(110) surfaces is markedly different when the substrate is held below 120 K and above 140 K. At 120 K, the development of core and valence level photoelectron emission spectra is consistent with charge transfer between the alkali metal and the surface atoms of a chemically undisrupted substrate. However, at 140 K, similar measurements show very different spectral changes, resembling more closely a reactive interface, involving interaction between the Na and bulk GaP atoms.