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Contactless THz-based bulk semiconductor mobility measurements using two-photon excitation.
Optics Express
|November 25, 2018
Summary
This study uses two-photon absorption for contactless mobility measurements in semiconductors like ZnSe and ZnTe. This method offers higher carrier density and reveals higher mobility in some materials compared to traditional techniques.
Area of Science:
- Solid-state physics
- Materials science
- Semiconductor physics
Background:
- Contactless characterization is crucial for semiconductor materials.
- Optical pump THz probe spectroscopy is a powerful tool for probing carrier dynamics.
- Two-photon absorption offers a unique excitation pathway for bulk materials.
Purpose of the Study:
- To investigate contactless bulk mobility measurements using two-photon absorption.
- To compare two-photon absorption with one-photon excitation for mobility determination.
- To explore the applicability of this technique across various semiconductor materials.
Main Methods:
- Optical pump THz probe experiments were conducted.
- Two-photon absorption was utilized for excitation, enabling bulk excitation.
- Contactless mobility measurements were performed on ZnSe, ZnTe, GaP, CdS, and GaSe.
Main Results:
- Two-photon absorption successfully excited samples to high carrier densities (10^13 carriers/cm^3 and higher).
- Measurable mobility signals were obtained through bulk excitation.
- For ZnTe and GaSe, two-photon excitation yielded higher mobility values than one-photon excitation.
Conclusions:
- Two-photon absorption is a viable method for contactless bulk mobility measurements.
- This technique provides insights into carrier dynamics in the entire sample volume.
- The findings highlight the potential of two-photon absorption for advanced semiconductor characterization.
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