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We have studied the composition, electron emission, and optical properties of CdS single crystals covered by a surface film of adsorbed Ba atoms with thickness Θ from 0.5 to 5 monolayers (ML). It is established that, as Θ increases up to 1 ML, yield depth λ of true secondary electrons (and photoelectrons) in the emission zone exhibits significant growth, which is explained by decreasing work function of the material surface. The further increase in Θ is accompanied by a decrease in both λ and photocurrent intensity values. It is found that no significant mutual diffusion of atoms at the Ba-CdS interface takes place at room temperature. Upon heating to T = 700 K, sulfur atoms exhibit intense diffusion into the Ba film and form a surface compound of the Ba 2 S type.

Auger electron spectroscopy combined with ion etching was used to study the effect of ion doping on the distribution profiles of atoms in silicon in contact with its surface. It has been established that preliminary implantation of Ba+ ions with E0=0.5-1 keV leads to a sharp decrease (by a factor of 10-12) in the diffusion length of oxygen and nickel atoms.

The composition, structure, and physicochemical properties of the surface and near-surface layers of silicon doped with low-energy (E0<5 keV) Ba+ and O2+ ions have been studied using a set of photoelectron and secondary electron spectroscopy methods. It has been established that in the process of ion implantation, chemical bonds are formed between the atoms of the alloying element and the matrix, the width of the energy bands and the density of electronic states in the bands change.