Ballistic electron spectroscopy
  We demonstrate the feasibility of ballistic electron spectroscopy as a new tool for mesoscopic physics. A quantum dot is utilised as an energy-selective detector of non-equilibrium ballistic electrons injected into a two-dimensional electron system. In this paper we use a second quantum dot as the electron injector to evaluate the scheme. We propose an application in the study of interacting 1D and 0D systems. 
F. Hohls, M. Pepper, J. P. Griffiths, G. A. C. Jones, and D. A.   Ritchie