Intersubband Excitations Research Articles

Observation of intersubband excitations in a multilayer two dimensional electron gas

We report the observation, by resonant inelastic light scattering, of intersubband excitations of the multilayer two dimensional electron gas, in modulation doped GaAsAlGaAs heterojunction superlattices. These are the first measurements of these transitions by any technique, and furnish intersubband energies in good agreement with calculated values. The spectral bands are broad, and nearly Lorentzian in shape: the implied relaxation rates scale linearly with band energy and are significantly faster than transport relaxation rates. Finally, the polarized spectra reveal differences between spin-flip and non spin-flip excitations which are unique to multilayer two dimensional electron gases.

Inelastic Light Scattering from a Quasi-Two-Dimensional Electron System in GaAs-AlxGa1−xAsHeterojunctions

Resonance enhanced inelastic light scattering from a quasi-two-dimensional electron gas confined at the interface of abruptly doped $\mathrm{GaAs}/n\ensuremath{-}{\mathrm{Al}}_{x}{\mathrm{Ga}}_{1\ensuremath{-}x}\mathrm{As}$ heterojunctions has been measured. The samples were fabricated using molecular-beam epitaxy with a high-contrast doping technique. The results show strong evidence for intersubband excitations in a two-dimensional electron system.