Single-dot spectroscopy via elastic single-electron tunneling through a   pair of coupled quantum dots
  We study the electronic structure of a single self-assembled InAs quantum dot by probing elastic single-electron tunneling through a single pair of weakly coupled dots. In the region below pinch-off voltage, the non-linear threshold voltage behavior provides electronic addition energies exactly as the linear, Coulomb blockade oscillation does. By analyzing it, we identify the s and p shell addition spectrum for up to six electrons in the single InAs dot, i.e. one of the coupled dots. The evolution of shell addition spectrum with magnetic field provides Fock-Darwin spectra of s and p shell. 
T. Ota, K. Ono, M. Stopa, T. Hatano, S. Tarucha, H. Z. Song, Y.   Nakata, T. Miyazawa, T. Ohshima, N. Yokoyama