Contact potential difference (CPD) measurements using a Kelvin probe coupled with synchrotron radiation are used to investigate various aspects of the problem of surface photovoltage (SPV) induced by the synchrotron radiation at (110) and (100) GaAs surfaces. A large and quasipermanent SPV is found at surfaces of low doped and low temperature (110) samples. SPV discharge mechanisms are investigated. Finally, the CPD technique is used to define conditions which minimize SPV and allow accurate measurements of band bending at low temperature. Band bending measurements are reported for interfaces between metals and (110) and (100) GaAs surfaces.
Christian Ludwig, Ajay Bhagwan Patil, Mohamed Tarik
Andras Kis, Dumitru Dumcenco, Olivier Renault, Dmitrii Unuchek, Hokwon Kim, Nicolas Chevalier
Marco Grioni, Helmuth Berger, Alberto Crepaldi, Daniela Pacilè