Sub-1K Cold Electron Transport At Room Temperature

Author

Anthony Martinez, University of Texas at ArlingtonFollow

ORCID Identifier(s)

ORCID 0000-0002-0624 4888

Graduation Semester and Year

Summer 2024

Language

English

Document Type

Dissertation

Degree Name

Doctor of Philosophy in Materials Science and Engineering

Department

Materials Science and Engineering

First Advisor

Seong Jin Koh

Abstract

Thermally excited electrons at the high-energy tail of the Fermi-Dirac distribution impose fundamental limitations on the performance of solid-state electronic and spintronic devices. For example, the thermally excited electrons obscure the Coulomb blockade essential for single-electron transport. The hot electrons can also overcome the energy barrier of Metal-Oxide-Semiconductor Field-Effect transistors (MOSFETs), causing unwanted leakage currents that lead to excessive power consumption in the integrated circuits. This study investigates an approach in which quantum states are used to manipulate electron tunneling, blocking the transport of thermally excited hot electrons, thereby enabling cold-electron transport at room temperature. Here two heterogeneous quantum wells (QW1 and QW2) having different effective masses (m*_QW1 > m*_QW2, where m*_QW1 and m*_QW2 are the effective electron masses of QW1 and QW2, respectively) effectively block or enable electron tunneling (QW switching) depending on the relative position of the two QW energies, E_QW1 and E_QW2. When E_QW1 is positioned below E_QW2, electron transport is blocked, whereas when E_QW1 is aligned with E_QW2 or E_QW1 is positioned above E_QW2, electron transport is enabled. The QW switching device consists of a source (Cr), QW1 (Cr₂O₃), QW2 (SnO_x, where x < 2), a tunneling barrier (native SiO₂), and a drain (p-type Si). The current-voltage (I-V) characteristics of the fabricated devices show abrupt current jumps (e.g., no thermal smearing) at a critical voltage V_crit of ~2.4 V, at which the QW1 and QW2 states align (E_QW1 = E_QW2). The differential conductance (dI/dV) plots show extremely narrow peak widths at V_crit, with the full width at half maximum (FWHM) only 0.25 mV at room temperature, which corresponds to an effective temperature of 0.8 K at room temperature. The ability to transport sub-1K cold electrons at room temperature opens the door for producing transistors with steep subthreshold slopes (

Keywords

Thermally Excited Electrons, Cold Electron Transport, Silicon, CMOS, Quantum Wells

Disciplines

Materials Science and Engineering

License

This work is licensed under a Creative Commons Attribution-No Derivative Works 4.0 International License.

Comments

Acknowledgements to:

Seong Jin Koh (Advisor)

National Science Foundation (NSF DMR-2122128, NSF ECCS-2031770)

Recommended Citation

Martinez, Anthony, "Sub-1K Cold Electron Transport At Room Temperature" (2024). Material Science and Engineering Dissertations. 87.
https://mavmatrix.uta.edu/materialscieng_dissertations/87