Electron interference effects in quantum wells: observation of bound and resonant states

Quasi-monoenergetic ballistic electrons were injected into GaAs potential wells of various thicknesses (29-72 nm). Strong modulation in the injected currents, as a function of the injection energy, was observed and correlated with electron coherence effects. A self-consistent solution of Poisson and Schroedinger equations was needed to relate these effects to the bound and, in particular, resonant quantum states in the well. The good match with theory justified the use (and led to an expression) of the electron 'energy effective mass' in the central valley, in an energy range where nonparabolicity and valley transfer are significant and make this determination, usually, difficult. (Author)