Energy Dependent Tunneling in a Quantum Dot
  We present measurements of the rates for an electron to tunnel on and off a quantum dot, obtained using a quantum point contact charge sensor. The tunnel rates show exponential dependence on drain-source bias and plunger gate voltages. The tunneling process is shown to be elastic, and a model describing tunneling in terms of the dot energy relative to the height of the tunnel barrier quantitatively describes the measurements. 
K. MacLean, S. Amasha, Iuliana P. Radu, D. M. Zumbuhl, M. A. Kastner,   M. P. Hanson, A. C. Gossard