Features of electrochemical processes at the boundary p-GaAs-HF water solution

Abstract

Investigated in this work are polarization curves typical for the interface p-GaAs-HF water solution with the concentration of fluoric acid between 1 and 10 mass.%. The shape of these curves has been compared with that following from analytical expressions obtained with account of the general equation for electrochemical kinetics. This equation was considered for partial cases of electrode potential re-distribution between the Helmholtz layers and the space charge region (SCR) in a semiconductor. It has been found that the shape of polarization curves corresponds to the state when exchange reactions at the above boundary for the used HF concentrations take place mainly via the valence band with participation of holes, while the electrode potential redistributes between the semiconductor SCR and the Helmholtz layer. Determined also have been the ranges of current density where transfer of current carriers takes place through the boundary p-GaAs-HF water solution (electrochemical stage), exchange currents for cathode and anode biases, coefficient of charge carrier transfer under the cathode bias.