Energy and spin polarization analysis of near band gap photoemission in AlGaAs/GaAs heterostructures

Near band gap photoemission from AlGaAs/GaAs heterostructures located close to a GaAs surface under negative electron affinity is performed by coadsorption of cesium and oxygen. This new technique provides detailed experimental informations on the energy levels of these systems. Energy distribution curves and analysis of the spin polarization of the emitted electrons allow us to obtain a clear picture of the energy and spin relaxation processes together with an understanding of the vertical transport through the structure towards the surface.