On the electrostatic contribution to the interfacial tension of semiconductor/gas and semiconductor/electrolyte interfaces
The concept of electrically charged surface states, which is well known in semiconductor surface physics, is connected with the thermodynamics of charged interfaces as developed in colloid chemistry and electrochemistry. Along these lines an interpretation is suggested of the phenomenon of the spontaneous bending of InSb wafers, discovered by Hanneman, Finn and Gatos. Experiments are described concerning contact angles of ionic solution droplets placed on etched Ge-surfaces, the droplets being provided with a Pt wire shaped electrode. The observations are interpreted in terms of slow states on these surface because the known relaxation times and state densities of slow states can easily be connected with the behaviour of the contact angles. Slow states are rather loosely defined as nonstable ionic, atomic and molecular configurations in which the chemical compounds which meet at the surface participate.