Photovoltaic investigations of GaAs/AlAs heterostructures.

We present the results of the application of photoresponse techniques to the study of the transport of electrons past an energy barrier. In this study, the barrier was provided by a thin layer of AlAs sandwiched between GaAs layers. The experiment measured the voltage resulting from the migration of optically excited electrons from one side of the barrier to the other. The voltage is measured as a function of the wavelength of the incident light. We also present the results of calculations which explain the nature of the observed spectra and how they change when the thickness of the top layer (the illuminated side) of GaAs is changed. [ABSTRACT FROM AUTHOR]