A new approach to control chemically the atomic structure and electronic properties of III-V compound semiconductors
is developed. This approach is based on the modification of chemical properties of anionic adsorbates (such as HS<sup>-</sup> ions)
prior to their adsorption on the surface. This is achieved through the solvation of the ions with different amphiprotic
solvents (water, alcohols). <i>Ab initio</i> quantum-chemical calculations show that the reactivity of solvated HS<sup>-</sup> ions depends essentially on composition of the solvation shell: hydrated ions are slightly electrophilic, whereas ions solvated by
alcohols are nucleophilic. Mechanism of interaction of such solvated ions with the semiconductor surface depends on the
solvent solvating the ion. Experimentally it is found that on adsorption of HS<sup>-</sup> ions from different solvents the As-S
bonds with solvent-dependent ionicity are formed on the surface. These surfaces possess different ionization energy and
electronic properties though now traces of solvent molecules are found in XPS spectra.