S. N. Kozlov

Sensitivity of porous silicon-nickel composite to methane adsorption

The effect of adsorbed methane molecules on the current-voltage characteristics of structures based on a porous silicon-nickel nanocomposite has been studied. The sample response exhibits a significant sensitivity to methane adsorption at temperatures above 75°C. A model is proposed that explains the observed effect.

Features of the charge transfer in nanoporous silicon nd silicon oxide with adsorbed water

The experimental plots of electric conductivity versus temperature for a porous silicon and a silicon oxide with adsorbed water exhibit features at temperatures significantly below 0°C, which are related to an ice-water phase transition in nanopores of the solid matrix.

Sensitivity of porous silicon-ferromagnetic metal composites to molecular hydrogen adsorption

The effect of molecular hydrogen adsorption on the current-voltage characteristics of structures based on porous silicon (por-Si) nanocomposites with nickel (por-Si-Ni) and cobalt (por-Si-Co) has been studied. The samples exhibit significant sensitivity to molecular hydrogen adsorption at a temperature of about 150°C. A model is proposed that explains the observed phenomena.

Optical charging of real surface of germanium over a wide range of temperatures

A study is made of the charging of a real germanium surface under the effect of light. Mechanisms of electron and hole transport from germanium to the oxide layer are discussed. Conclusions are drawn as to the nature of the deep electron and hole traps in the oxide.

Studying the interaction of methane and oxygen with the surface of a porous silicon-ferromagnetic metal nanocomposite

The influence of the adsorption of methane and oxygen on the current-voltage characteristics of metal/porous silicon-ferromagnetic metal/crystalline silicon heterostructures has been studied. A qualitative model is proposed that explains the obtained results. It is established that structures based on the silicon-porous silicon system can be used to create methane sensors capable of detecting this gas on the background of atmospheric air at elevated temperatures.

The effect of illumination on the electric and photoelectric properties of μc-Si: H films weakly doped with boron

The electric conductivity and photoconductivity of μc-Si: H films weakly doped with boron increase upon exposure of the samples to light in the band of intrinsic absorption. It is shown that the effect is related to changes in the ambient medium, probably, to the photoinduced charging of oxygen molecules adsorbed on the μc-Si: H films.

Adsorption-controllable channel conductivity in oxidized porous silicon

It is shown that an adsorption field acting on a silicon-oxidized-porous-silicon-metal structure can create a “frozen” state with conductivity increased by a factor of hundreds or thousands. The effect is associated with the modulation of the channel conductivity of oxidized silicon filaments of fractal material by ionic charge migrating along the surface of the oxidized layer.

Determination of the energy diagram of a dielectric-semiconductor structure from the photocharging spectra of the dielectric

The Ge-GeO2 and Si-SiO2 structures are investigated by the method of optical charging of traps in the dielectric. It is shown that by measuring the photocharging spectrum in a wide temperature range, one may obtain information on the boundaries of delocalized states of the dielectric as well as on the dimensions of the “tails” of fluctuation localized states.

Effect of doping germanium oxide with metal ions on optical charge “memory” in Ge-GeO2 system

The paper presents the results of experiments aimed at ascertaining the possibility of controlling the “photomemory” in the Ge-GeO2 system by the technique of doping the oxide layer with metal ions. It is shown that under certain conditions doping of such a system with Na, K, Cs, Cr, and Ti ions results in the formation of deep electron traps which are recharged under illumination. A study was made of how heating in a vacuum and in oxygen as well as adsorption of water and ammonia affect the optical charging and the density of fast surface states for doped specimens.

“Superslow” processes in the Ge-GeO2 system

A study was made of the charged state on a natural or an oxidized germanium surface during heat-and-field treatment. This study dealt with the kinetics of charging and discharging of “superslow” surface states. The thermal activation energy of these charging and discharging processes has also been evaluated. Conclusions are drawn about the possible nature of “superslow” traps in the Ge-GeO2 system.