Journal article
Terahertz conductivity analysis for highly doped thin-film semiconductors
- Abstract:
- The analysis of terahertz transmission through semiconducting thin films has proven to be an excellent tool for investigating optoelectronic properties of novel materials. Terahertz time-domain spectroscopy (THz-TDS) can provide information about phonon modes of the crystal, as well as the electrical conductivity of the sample. When paired with photoexcitation, optical-pump-THz-probe (OPTP) technique can be used to gain an insight into the transient photoconductivity of the semiconductor, revealing the dynamics and the mobility of photoexcited charge carriers. As the relation between the conductivity of the material and the THz transmission function is generally complicated, simple analytical expressions have been developed to enable straightforward calculations of frequency-dependent conductivity from THz-TDS data in the regime of optically thin samples. Here, we assess the accuracy of these approximated analytical formulas in thin films of highly doped semiconductors, finding significant deviations of the calculated photoconductivity from its actual value in materials with background conductivity comparable to 102Ω− 1cm− 1. We propose an alternative analytical expression, which greatly improves the accuracy of the estimated value of the real photoconductivity, while remaining simple to implement experimentally. Our approximation remains valid in thin films with high dark conductivity of up to 104Ω− 1cm− 1 and provides a very high precision for calculating photoconductivity up to 104Ω− 1cm− 1, and therefore is highly relevant for studies of photoexcited charge-carrier dynamics in electrically doped semiconductors. Using the example of heavily doped thin films of tin-iodide perovskites, we show a simple experimental method of implementing our correction and find that the commonly used expression for photoconductivity could result in an underestimate of charge-carrier mobility by over 50%.
- Publication status:
- Published
- Peer review status:
- Peer reviewed
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(Preview, Version of record, 3.6MB, Terms of use)
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- Publisher copy:
- 10.1007/s10762-020-00739-6
Authors
+ Engineering & Physical Sciences Research Council
More from this funder
- Grant:
- EP/M017095/1
- EP/P006329/1
- Publisher:
- Springer
- Journal:
- International Journal of Infrared and Millimeter Waves More from this journal
- Volume:
- 41
- Issue:
- 12
- Pages:
- 1431–1449
- Publication date:
- 2020-09-15
- Acceptance date:
- 2020-08-19
- DOI:
- ISSN:
-
0195-9271
- Language:
-
English
- Keywords:
- Pubs id:
-
1127188
- Local pid:
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pubs:1127188
- Deposit date:
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2020-08-19
Terms of use
- Copyright holder:
- Ulatowski, AM et al.
- Copyright date:
- 2020
- Rights statement:
- © The Author(s) 2020. Open Access. This article is licensed under a Creative Commons Attribution 4.0 International License, which permits use, sharing, adaptation, distribution and reproduction in any medium or format, as long as you give appropriate credit to the original author(s) and the source, provide a link to the Creative Commons licence, and indicate if changes were made. The images or other third party material in this article are included in the article's Creative Commons licence, unless indicated otherwise in a credit line to the material. If material is not included in the article's Creative Commons licence and your intended use is not permitted by statutory regulation or exceeds the permitted use, you will need to obtain permission directly from the copyright holder.
- Licence:
- CC Attribution (CC BY)
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