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Orbital photogalvanic effects in quantum-confined structures
J Karch1, S A Tarasenko, P Olbrich
1Terahertz Center, University of Regensburg, 93040 Regensburg, Germany.
Summary
We observed circular and linear photogalvanic effects in silicon electron channels using terahertz radiation. The circular effect arises from quantum interference, demonstrating its orbital nature in these silicon-based structures.
Area of Science:
- Solid State Physics
- Terahertz Spectroscopy
- Semiconductor Physics
Background:
- Photogalvanic effects are crucial for understanding light-matter interactions in semiconductors.
- Free-carrier absorption of terahertz radiation in silicon presents unique opportunities for optoelectronic applications.
Purpose of the Study:
- To investigate circular and linear photogalvanic effects in silicon electron channels.
- To explore the influence of radiation polarization, wavelength, gate voltage, and temperature on photocurrent.
- To develop a theoretical framework explaining the observed photogalvanic phenomena.
Main Methods:
- Experimental measurements of photocurrent in silicon surfaces under terahertz radiation.
- Systematic variation of radiation polarization, wavelength, gate voltage, and temperature.
- Development of microscopic and phenomenological theories for photogalvanic effects.
Main Results:
- Observed and characterized circular and linear photogalvanic effects in (001)-oriented and miscut silicon surfaces.
- Demonstrated the dependence of photocurrent on various experimental parameters.
- Established that the circular photogalvanic effect is of pure orbital nature due to quantum interference.
Conclusions:
- The developed theory accurately describes the experimental findings of photogalvanic effects in silicon.
- The circular photogalvanic effect in silicon structures is confirmed to be orbital, arising from quantum interference.
- This study provides fundamental insights into terahertz-driven photocurrents in silicon.
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