Oscillations in the photocurrent from quantum dots: Geometric information from reciprocal spectra

We demonstrate that the current of photoelectrons from a quantum dot exhibits oscillations as a function of the photon energy owing to the predominant ionization from the dot boundary. In the Fourier reciprocal space of the photoelectron wave vector these oscillations reveal frequencies connected to the confinement range. We attribute the oscillation in the recent photocurrent measurements by Fry et al. (PRL 84, 733 (2000)) to this phenomenon. Angle-resolved and angle-integrated experiments with the focus on directly imaging the confining potential are suggested.