NEES Teleseminars

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NEES Teleseminar: John Cumings
Thursday, March 13, 2014
4:00 p.m.
For More Information:
Elizabeth Lathrop
301 405 7801

Electron Holography of Biased SiNW P-N Junction & CNT Devices by John Cumings, Materials Sciences & Engineering, UMD


We report an in situ examination of individual Si p–n junction nanowires (NWs) using off-axis electron holography (EH) during transmission electron microscopy. The SiNWs were synthesized by chemical vapor deposition with an axial dopant profile from n- to p-type, and then placed inside the transmission electron microscope as a cantilever geometry in contact with a movable Pt probe for in situ biasing measurements during simultaneous EH observations. The phase shift from EH indicates the potential shift between the p- and n-segments to be 1.03 ± 0.17 V due to the built-in voltage. The I–V characteristics of a single SiNW indicate the formation of a Schottky barrier between the NW tip and the movable Pt contact. EH observations show a strong concentration of electric field at this contact, preventing a change in the Si energy bands in the p–n junction region due to the applied bias. 

Reference: K. He, J.H. Cho, Y. Jung, S.T. Picraux, J. Cumings, Nanotechnology, 2013, 24 (11) 115703 DOI: 10.1088/0957-4484/24/11/115703

This Event is For: Graduate • Faculty • Post-Docs

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