Energy-filtered cold electron transport at room temperature.

Nature Communications 2014 Sep 10;5:4745.

Bhadrachalam P (1), Subramanian R (1), Ray V (1), Ma LC (1), Wang W (2), Kim J (2), Cho K (2), Koh SJ (1).

1Department of Materials Science and Engineering, University of Texas at Arlington, Arlington, Texas 76019, USA Nanotechnology Research Center, University of Texas at Arlington, Arlington, Texas 76019, USA.

2Department of Materials Science and Engineering, University of Texas at Dallas, Richardson, Texas 75080, USA.

 

ABSTRACT

Fermi-Dirac electron thermal excitation is an intrinsic phenomenon that limits functionality of various electron systems. Efforts to manipulate electron thermal excitation have been successful when the entire system is cooled to cryogenic temperatures, typically <1 K. Here we show that electron thermal excitation can be effectively suppressed at room temperature, and energy-suppressed electrons, whose energy distribution corresponds to an effective electron temperature of ~45 K, can be transported throughout device components without external cooling. This is accomplished using a discrete level of a quantum well, which filters out thermally excited electrons and permits only energy-suppressed electrons to participate in electron transport. The quantum well (~2 nm of Cr2O3) is formed between source (Cr) and tunnelling barrier (SiO2) in a double-barrier-tunnelling-junction structure having a quantum dot as the central island. Cold electron transport is detected from extremely narrow differential conductance peaks in electron tunnelling through CdSe quantum dots, with full widths at half maximum of only ~15 mV at room temperature.

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Significance Statement

Applications of this technology that could reduce energy use is wearable computers with self-contained power sources. Another application could in developing smartphones that don’t die after few hours of heavy use.

 

Brian Ho

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