The Influence of Temperature on the Lateral Photovoltaic Effect in the Fe3O4/SiO2/n-Si Structure

We report on the results of a study of the lateral photovoltaic effect in the Fe3O4/SiO2/n-Si(001) structure at temperatures of 300 and 122 K under continuous and pulsed illumination. It is found that when the temperature changes from 300 to 122 K, the LPE sensitivity decreases from 112 to 65 mV/mm. At pulsed illumination, an increase of rise time and a fall time is observed with decreasing temperature. From a consideration of the energy band diagrams and equivalent circuits of the Fe3O4/SiO2/n-Si structure, it is assumed that the detected temperature effects of LPE are due to the strong dependence of the magnetite film resistance on temperature.

The Lateral Photovoltaic Effect in the Fe3O4/SiO2/p-Si Structure

We report on the results of the study of the lateral photovoltaic effect in the Fe3O4/SiO2/p-Si structure. It is found that maximum of the lateral photovoltage is localized near the measuring contacts and rapidly attenuates when the light spot moves away from them. Correspondence of the photovoltage sign to the conductivity type of the silicon substrate is achieved only taking into account the interface states at the SiO2/p-Si interface. The extreme dependence of the lateral photovoltage on the thickness of the Fe3O4film is observed, which is due to the fact that the barrier height is laterally inhomogeneous at small thicknesses of magnetite film, whereas at higher thicknesses of the film the lateral photovoltaic effect is short-circuited by this film.

Effects of Deposition Potentials on the Morphology and Structure of Iron-Based Films on Carbon Steel Substrate in an Alkaline Solution

The purpose of this work is to investigate the effect of electrochemical deposition potential on the morphology and structure of iron-based films on the carbon steel in an alkaline Fe(III)-triethanolamine solution. The deposition potentials were controlled in the range from −1.05 to −1.23 VSCEfor 1800 s at 80°C. Total amount of electric charge for electrodeposition process was increased with increasing deposition potential in negative direction. Pure magnetite films with a columnar and defect-free structure were deposited in the potential range from −1.05 VSCEto −1.11 VSCE. However, petal-like magnetite film containing ferrihydrite and iron was formed at −1.17 VSCE. At more negative potential of −1.23 VSCE, two distinct layers were observed: a porous outer layer containing ferrihydrite and goethite and a compact inner layer consisting of columnar metallic iron. In the potential range from −1.05 to −1.11 VSCE, the pure magnetite films gradually increased the thickness and decreased the surface roughness with an increase of the overpotential. The magnetite film deposited at −1.11 VSCEshowed the most thick layer and smooth surface state.