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Observation of Strong Reflection of Electron Waves Exiting a Ballistic Channel at Low Energy



Jason Campbell, Jason Ryan, Kin P. Cheung, David J. Gundlach, Changze Liu, Canute I. Vaz, Richard G. Southwick III, Anthony S. Oates, Ru Huang


Wave scattering by a potential step is a nearly ubiquitous concept. Thus, it is surprising that theoretical treatments of ballistic transport in nanoscale devices, from quantum point contacts to ballistic transistors, assume no reflection even when the potential step is encountered upon exiting the device. Experiments so far seem to support this even if it not clear why. Here we report clear evidence of coherent reflection when electron wave exits the channel of a nanoscale transistor and when the electron energy is low. The observed behavior is well described by a simple rectangular potential barrier model which the Schrodinger's equation can be solved exactly. We can explain why reflection is not observed in most situations but cannot be ignored in some important situations. Our experiment also represents a direct measurement of electron injection velocity - a critical quantity in nanoscale transistors that is widely considered not measurable.
AIP Advances


Quantum interference, nanoscale device, MOSFET, reflectionless contact, injection velocity


Campbell, J. , Ryan, J. , Cheung, K. , Gundlach, D. , Liu, C. , Vaz, C. , Southwick III, R. , Oates, A. and Huang, R. (2016), Observation of Strong Reflection of Electron Waves Exiting a Ballistic Channel at Low Energy, AIP Advances, [online], (Accessed April 21, 2024)
Created June 9, 2016, Updated October 14, 2021