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Light Emission in Metal-Semiconductor Tunnel Junctions: Direct Evidence for Electron Heating by Plasmon Decay
Guy Shalem1, Omer Erez-Cohen1, Diana Mahalu1
1Department of Condensed Matter Physics, Weizmann Institute of Science, Rehovot 7610001, Israel.
Nano Letters
|January 26, 2021
Summary
We observed light emission from plasmon-assisted tunneling in gold-insulator-semiconductor devices. Electron temperature increased linearly with voltage, driven by plasmon decay, exceeding applied energy thresholds.
Area of Science:
- Solid State Physics
- Materials Science
- Nanotechnology
Background:
- Metal-insulator-semiconductor tunnel junctions are crucial electronic components.
- Understanding electron transport and energy dynamics in these junctions is key for device optimization.
Purpose of the Study:
- To investigate light emission mechanisms in gold-Al2O3-silicon tunnel junctions.
- To explore the role of plasmons in inelastic electron tunneling and energy transfer.
Main Methods:
- Fabrication of patterned gold/Al2O3/p-type silicon tunnel junctions.
- Electrical characterization and optical emission spectroscopy.
- Analysis of emission spectra to determine electron temperature and distribution.
Main Results:
- Observed light emission attributed to plasmon-assisted inelastic tunneling.
- Emission cutoff energy exceeding applied voltage (ħω > eV), indicating non-equilibrium processes.
- Emission spectrum consistent with Fermi-Dirac distribution, revealing effective electron temperature (Te).
- Te showed a linear dependence on applied voltage.
Conclusions:
- Plasmon decay at the gold electrode is the primary mechanism for electron heating.
- Electrically driven plasmons significantly influence energy transfer in these devices.
- The findings provide insights into fundamental electron dynamics and light emission in nanoscale junctions.
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