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Determining the Location and Cause of Unintentional Quantum Dots in a Nanowire



Ted C. Thorbeck, Neil M. Zimmerman


Unintentional quantum dots are a common problem for single electron devices in both silicon and carbon. To determine the cause of these dots it is helpful to know their size and location. Because each dot is capacitively coupled to multiple gates, we can stereoscopically determine the location and size of the dots. Using a capacitance simulation we determined what sizes and locations are consistent with our measured capacitances, with a precision of several nanometers. Because we observe unintentional dots in the same location of the wire in multiple devices, we suggest the cause of the dots is a systematic but not deliberate consequence of the fabrication. This is in contrast to the typical assumption in the field that unintentional dots are caused by random atomic-scale defects such as interface traps. We also propose techniques to eliminate them from future devices
Nano Letters


silicon single electron transistors, unintentional quantum dots, double quantum dot


Thorbeck, T. and Zimmerman, N. (2012), Determining the Location and Cause of Unintentional Quantum Dots in a Nanowire, Nano Letters (Accessed April 12, 2024)
Created March 21, 2012, Updated February 19, 2017