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Updated: Jun 17, 2026
08:53
Angle-resolved Photoemission Spectroscopy At Ultra-low Temperatures
Published on: October 9, 2012
Escape probability of photoelectrons into vacuum
1AF Avionics Laboratory (AFSC),Wright-Patterson AFB, Ohio 45433, USA.
Applied Optics
|January 14, 2010
Summary
Infrared spectral response degradation in photocathodes like S-11 and S-20 is mainly due to poor photoelectron escape probability, not absorption issues. This finding helps optimize photocathode performance for infrared applications.
Area of Science:
- Photocathode physics
- Optical spectroscopy
- Solid-state electronics
Background:
- Photocathodes exhibit reduced spectral response in the infrared (IR) region.
- Understanding the causes of this IR degradation is crucial for improving detector performance.
Purpose of the Study:
- To compare the quantum efficiency of S-11 and S-20 photocathodes.
- To determine the primary cause of IR spectral response degradation in photocathodes.
- To estimate the photoelectron escape probability as a function of photon energy.
Main Methods:
- Utilized an absorption diffusion model to analyze photocathode quantum efficiency.
- Compared model-derived quantum efficiency with ITT spectral response curves for S-11 and S-20 photocathodes.
- Calculated the ratio of quantum efficiencies to isolate the impact of different factors.
Main Results:
- The comparison revealed that IR degradation is predominantly caused by a low photoelectron escape probability over the surface potential barrier.
- Absorption was found to be less significant in causing the observed IR spectral response decrease.
- An escape probability function was estimated and plotted against photon energy.
Conclusions:
- The surface potential barrier significantly impacts photoelectron escape, leading to IR spectral response limitations.
- The absorption diffusion model, combined with experimental data, effectively elucidates photocathode performance limitations.
- This research provides insights for designing improved photocathodes with enhanced IR sensitivity.
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