Observation of strong reflection of electron waves exiting a ballistic channel at low energy

AIP Advances. 2016;6(6):065212-065212-9 DOI 10.1063/1.4954083

 

Journal Homepage

Journal Title: AIP Advances

ISSN: 2158-3226 (Online)

Publisher: AIP Publishing LLC

Society/Institution: American Institute of Physics

LCC Subject Category: Science: Physics

Country of publisher: United States

Language of fulltext: English

Full-text formats available: PDF, HTML

 

AUTHORS

Canute I. Vaz (National Institute of Standards and Technology, Gaithersburg, MD 20899-8120, USA)
Changze Liu (National Institute of Standards and Technology, Gaithersburg, MD 20899-8120, USA)
Jason P. Campbell (National Institute of Standards and Technology, Gaithersburg, MD 20899-8120, USA)
Jason T. Ryan (National Institute of Standards and Technology, Gaithersburg, MD 20899-8120, USA)
Richard G. Southwick III (National Institute of Standards and Technology, Gaithersburg, MD 20899-8120, USA)
David Gundlach (National Institute of Standards and Technology, Gaithersburg, MD 20899-8120, USA)
Anthony S. Oates (Taiwan Semiconductor Manufacturing Corporation, Hsinchu 30844, Taiwan)
Ru Huang (Institute of Microelectronics, Peking University, Beijing 100871, China)
Kin. P. Cheung (National Institute of Standards and Technology, Gaithersburg, MD 20899-8120, USA)

EDITORIAL INFORMATION

Peer review

Editorial Board

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Time From Submission to Publication: 9 weeks

 

Abstract | Full Text

Wave scattering by a potential step is a 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 is 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.