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

Quasimonoenergetic ballistic electrons were injected into GaAs potential wells of various thicknesses (2972 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 Schrödinger 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. © 1987 The American Physical Society.