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Raman Spectroscopy as a Simple yet Effective Analytical Tool for Determining Fermi Energy and Temperature Dependent
Chanchal Rani1, Manushree Tanwar1, Tanushree Ghosh1
1Materials and Device Laboratory, Department of Physics, Indian Institute of Technology Indore, Simrol 453552, India.
Analytical Chemistry
|January 7, 2022
Summary
Determining the Fermi energy and thermal Fermi shift in semiconductors is challenging. Temperature-dependent Raman spectroscopy offers a powerful, straightforward method for their simultaneous experimental determination in doped silicon.
Area of Science:
- Condensed Matter Physics
- Materials Science
- Spectroscopy
Background:
- Fermi energy and its temperature dependence are critical semiconductor properties.
- Simultaneous experimental determination of Fermi energy and thermal Fermi shift is experimentally challenging.
Purpose of the Study:
- To introduce and validate temperature-dependent Raman spectromicroscopy as a technique for determining Fermi energy and thermal Fermi shift.
- To demonstrate the applicability of this method for extrinsic semiconductors, specifically n- and p-type silicon.
Main Methods:
- Utilized temperature-dependent Raman spectromicroscopy on doped silicon samples.
- Analyzed the asymmetrically broadened Raman spectral line-shape, specifically Fano coupling strength.
- Developed a formula based on theoretical frameworks to calculate Fermi level position from Raman observables.
Main Results:
- Raman spectral line-shape parameters were successfully used to determine Fermi energy and thermal Fermi shift.
- The developed formula accurately calculates the Fermi level position in both n- and p-type silicon.
- Temperature-dependent variations of the Fermi level position align with existing reports.
Conclusions:
- Temperature-dependent Raman spectroscopy is a powerful and accessible technique for characterizing Fermi energy and thermal Fermi shift.
- The developed Raman-based formulation provides a reliable method for calculating these crucial semiconductor parameters.
- This approach overcomes the difficulties associated with the simultaneous experimental determination of Fermi energy and its temperature dependence.
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