Electroreflectance bias-wavelength mapping of the modulation Si delta-doped pseudomorphic GaAs/InGaAs/AlGaAs structure

The electroreflectance bias-wavelength mapping is proposed as a tool for ch aracterization of low-dimensional structures. The results of room-temperatu re measurements on modulation Si delta-doped pseudomorphic GaAs/InGaAs/AlGa As heterostructure with high mobility two-dimensional electron gas are pres ented. Franz-Keldysh oscillations (FKO) in GaAs layer are analyzed using fa st Fourier transform (FFT) mapping in order to find an electric field in th e GaAs layer. Two frequencies of FKO are identified in the FFT spectra, whi ch are attributed to transitions involving heavy and light holes. Two trans itions within the InGaAs quantum well are found at zero bias and an additio nal transition becomes apparent in reversely biased structure. Spectral fea tures due to spin-orbit split holes in GaAs, back AlGaAs barrier, and AlGaA s/GaAs superlattice are also identified. (C) 1999 American Institute of Phy sics. [S0003-6951(99)02540-1].