aInstitute of Physics, Wroclaw University of Technology, Wybrzeże Wyspiańskiego 27, 50-370 Wrocław, Poland
bInstitute of Microsystem Technology, Wroclaw University of Technology, Janiszewskiego 11/17, 50-372 Wrocław, Poland
Abstract:
Photoreflectance (PR) spectroscopy has been applied to the investigation of Si δ-doped GaAs, Al0.35Ga0.65As and AlAs layers grown by metal–organic vapor phase epitaxy (MOVPE) on GaAs substrates. The observation of Franz–Keldysh oscillations (FKO) and the application of fast Fourier transform (FFT) has allowed us to determine the internal electric field and, hence, the potential barrier between surface and δ-doped region of the layer. The FFT of the photoreflectance spectra has exhibited two separate heavy and light hole frequencies showing that the FKO in the PR signal are always the superposition of these two components.