Observations of GaAs/CaF2 heterointerface formation by electron beam surface modification and its effects

We investigated the electron beam induced surface modification of CaF2(111) and initial stage of GaAs growth on the modified CaF2 surface using the surface photoabsorption (SPA) method and atomic force microscopy (AFM). The CaF2 surface was modified by 300 eV electron beam irradiation at 200 degrees C in a As-4 molecular beam. The amount of adsorbed As atoms increased with electron dose and it follows Langmuir adsorption principle and saturated at a value equivalent to 1 monolayer (ML) adsorption. AFM observation of GaAs grown on this modified surface clarified that the sticking coefficient and the wettability of GaAs on CaF2 surface was drastically improved by the surface modification.