Electro-reflectance in conducting thin films in the infra-red

Most electro-reflectance experiments have been carried out in the visible and UV parts of the electromagnetic spectrum. Axe and Hammer (1967), however, are the only research workers who observed a qualitative modulation peak in the IR and in the vicinity of the reflectance plasma edge of Ge- and tin-doped GaAs. Large absorption corrections were required due to the absorption by the saturated methanol–NaCl electrolyte solution used. Their results were not reproducible, but indicate that a rather large effect should be expected. The scope of the work reported here was to extend ER studies associated with free electron effects into the near IR and obtain valuable quantitative results in order to develop and evaluate a microscopic theory.