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Electron-Transport Characteristics through Aluminum Oxide (100) and (012) in a Metal-Insulator-Metal Junction System:
Ji Il Choi1, Han Seul Kim2, Young Shik Shin3
1Computational NanoBio Technology Laboratory, School of Materials Science and Engineering, Georgia Institute of Technology, 771 Ferst Drive NW, Atlanta, Georgia 30332-0245, United States.
ACS Omega
|February 4, 2020
Summary
Electron transport in aluminum oxide (Al2O3) junctions depends on crystallographic orientation. The Al2O3(012) facet shows significantly higher current at finite bias due to better electron transport channels.
Area of Science:
- Materials Science
- Condensed Matter Physics
- Nanotechnology
Background:
- Aluminum oxide (Al2O3) is crucial for electronic devices due to its mechanical and insulating properties.
- Understanding electron transport in Al2O3 is essential for nanoscale electronic applications.
- Previous investigations lacked a thorough analysis of electron transport mechanisms in Al2O3 nanostructures.
Purpose of the Study:
- To investigate electron transport mechanisms in Al2O3 across different crystallographic facets.
- To analyze electron transport in metal-insulator-metal junctions using Al2O3(100) and Al2O3(012) facets.
- To elucidate the role of the contact interface in determining the insulating properties of Al2O3.
Main Methods:
- Density functional theory (DFT) combined with the nonequilibrium Green function (NEGF) method.
- Simulation of electron transport through Al2O3(100) and Al2O3(012) facets in a metal-insulator-metal junction.
- Analysis of transmission functions and conductance under zero and finite bias voltages.
Main Results:
- Transmission function T(E) decreases with energy in the (E - EF) < 0 regime.
- Characteristic behaviors of T(E) were observed for Al2O3(100) and Al2O3(012) in the (E - EF) > 0 regime, with peaks shifting to lower energies under bias.
- Conductance decay rates at zero bias were similar for both facets, indicating minor contact interface contribution.
- A significant increase in electrical current was observed for the Al2O3(012) junction at bias > 0.7 V compared to Al2O3(100).
Conclusions:
- The Al2O3(012) facet exhibits superior electron transport characteristics at finite bias due to well-developed eigenchannels.
- The contact interface plays a critical role in the insulating properties of Al2O3-Pt junctions under finite bias conditions.
- Crystallographic orientation significantly influences electron transport behavior in Al2O3-based electronic devices.
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