The Importance of Schottky Barrier Height in Plasmonically Enhanced Hot‐Electron Devices

Plasmonically enhanced hot‐electron (PEH) photodiodes are a new class of optoelectronic device with the potential to be selective to spectral position, polarization, and bandwidth. Reported solid‐state PEH devices based on metal nanoparticles generally have low performance, in part, due to low colle...

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Bibliographic Details
Published in:Advanced optical materials 2021-02, Vol.9 (3), p.n/a
Main Authors: Zhao, Shenyou, Yin, Yanting, Peng, Jun, Wu, Yiliang, Andersson, Gunther G., Beck, Fiona J.
Format: Article
Language:English
Subjects:
Atomic layer epitaxy
Correlation analysis
Efficiency
Energy levels
Hot electrons
Material properties
Materials science
Nanoparticles
Optics
Optoelectronic devices
optoelectronics
Photodiodes
photoelectron spectroscopy
plasmonics
Quantum efficiency
Schottky barrier height
Titanium dioxide
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Summary:Plasmonically enhanced hot‐electron (PEH) photodiodes are a new class of optoelectronic device with the potential to be selective to spectral position, polarization, and bandwidth. Reported solid‐state PEH devices based on metal nanoparticles generally have low performance, in part, due to low collection efficiency of photogenerated hot electrons. A correlation is found between the measured external quantum efficiency (EQE) and the temperature at which the ALD‐TiO2 is deposited by atomic layer deposition (ALD) in Au–TiO2‐based PEH photodiodes. By investigating the material properties of the TiO2, it is demonstrated that the change in EQE is driven by a change in the energy levels in the semiconductor. The results show that lowering the implied Schottky barrier height increases the collection efficiency of hot electrons over the junction, in agreement with existing analytical models. This work demonstrates the crucial role that barrier height plays in hot electron devices in general, and indicates that this is an important design consideration for the improvement of PEH photodetectors. A correlation is found between the internal quantum efficiency of plasmonically enhanced, Au nanoparticle–TiO2 hot‐electron photodiodes, and the temperature at which the TiO2 is deposited. Improved efficiencies are attributed to lowering the Schottky barrier that increases the collection efficiency of hot electrons over the junction, demonstrating the crucial role of the barrier height in hot‐electron devices.
ISSN:2195-1071
2195-1071
DOI:10.1002/adom.202001121