Ultrafast photoconductivity dynamics in narrow-gap HgCdTe films
Mercury cadmium telluride (Hg1−xCdxTe or MCT) is the premier material for infrared detection. However, despite its importance, studies exploring the ultrafast photoresponse in this semiconductor alloy are limited. Here, we use time-resolved terahertz spectroscopy to perform a detailed study of the p...
Saved in:
| Main Authors: | , , , , , , , , , , |
|---|---|
| Format: | Article |
| Language: | English |
| Published: |
AIP Publishing LLC
2024-12-01
|
| Series: | APL Materials |
| Online Access: | http://dx.doi.org/10.1063/5.0235571 |
| Tags: |
Add Tag
No Tags, Be the first to tag this record!
|
| _version_ | 1846093480543125504 |
|---|---|
| author | N. B. Refvik D. N. Purschke C. E. Jensen W. Pan H. R. J. Simpson W. Lei R. Gu J. Antoszewski G. A. Umana-Membreno L. Faraone F. A. Hegmann |
| author_facet | N. B. Refvik D. N. Purschke C. E. Jensen W. Pan H. R. J. Simpson W. Lei R. Gu J. Antoszewski G. A. Umana-Membreno L. Faraone F. A. Hegmann |
| author_sort | N. B. Refvik |
| collection | DOAJ |
| description | Mercury cadmium telluride (Hg1−xCdxTe or MCT) is the premier material for infrared detection. However, despite its importance, studies exploring the ultrafast photoresponse in this semiconductor alloy are limited. Here, we use time-resolved terahertz spectroscopy to perform a detailed study of the picosecond charge carrier dynamics in long-wave infrared Hg1−xCdxTe (x ∼ 0.2) films, providing insight into ultrafast carrier cooling and temperature-dependent scattering mechanisms. Due to the multilayer photoexcited sample geometry, an elementary thin-film analysis leads to a negative photoconductivity artifact. We, therefore, derive a modified thin-film photoconductivity formula to accurately extract a Drude photoconductivity spectrum. In our analysis, we include the effects of carrier diffusion and the conduction band non-parabolicity in Hg1−xCdxTe. We extract ultrahigh electron mobilities as large as 6 × 105 cm2 V−1 s−1 at 25 K. At cryogenic temperatures, we find the photoexcited electron mobility is up to four times larger than the dark mobility, which we attribute to suppression of ionized impurity scattering due to hole capture by acceptor-type Hg vacancies. In addition, after photoexcitation, we observe a relatively slow rise in photoconductivity over a 10 ps timescale with a monotonically increasing carrier scattering time and a carrier effective mass that decays exponentially with a time constant of 1.9 ps, which we attribute to hot-carrier cooling dynamics in the non-parabolic conduction band. |
| format | Article |
| id | doaj-art-f47a6f4bf2e94f8a9505c5b795a9d9dc |
| institution | Kabale University |
| issn | 2166-532X |
| language | English |
| publishDate | 2024-12-01 |
| publisher | AIP Publishing LLC |
| record_format | Article |
| series | APL Materials |
| spelling | doaj-art-f47a6f4bf2e94f8a9505c5b795a9d9dc2025-01-02T17:16:14ZengAIP Publishing LLCAPL Materials2166-532X2024-12-011212121116121116-1010.1063/5.0235571Ultrafast photoconductivity dynamics in narrow-gap HgCdTe filmsN. B. Refvik0D. N. Purschke1C. E. Jensen2W. Pan3H. R. J. Simpson4W. Lei5R. Gu6J. Antoszewski7G. A. Umana-Membreno8L. Faraone9F. A. Hegmann10Department of Physics, University of Alberta, Edmonton, Alberta T6G 2E1, CanadaJoint Attosecond Science Laboratory, National Research Council of Canada & University of Ottawa, Ottawa, Ontario K1N 5A2, CanadaDepartment of Physics, University of Alberta, Edmonton, Alberta T6G 2E1, CanadaARC Centre of Excellence on Transformative Meta-Optical Systems (TMOS), Department of Electrical, Electronic and Computer Engineering, The University of Western Australia, Western Australia 6009, AustraliaDepartment of Physics, University of Alberta, Edmonton, Alberta T6G 2E1, CanadaARC Centre of Excellence on Transformative Meta-Optical Systems (TMOS), Department of Electrical, Electronic and Computer Engineering, The University of Western Australia, Western Australia 6009, AustraliaARC Centre of Excellence on Transformative Meta-Optical Systems (TMOS), Department of Electrical, Electronic and Computer Engineering, The University of Western Australia, Western Australia 6009, AustraliaARC Centre of Excellence on Transformative Meta-Optical Systems (TMOS), Department of Electrical, Electronic and Computer Engineering, The University of Western Australia, Western Australia 6009, AustraliaARC Centre of Excellence on Transformative Meta-Optical Systems (TMOS), Department of Electrical, Electronic and Computer Engineering, The University of Western Australia, Western Australia 6009, AustraliaARC Centre of Excellence on Transformative Meta-Optical Systems (TMOS), Department of Electrical, Electronic and Computer Engineering, The University of Western Australia, Western Australia 6009, AustraliaDepartment of Physics, University of Alberta, Edmonton, Alberta T6G 2E1, CanadaMercury cadmium telluride (Hg1−xCdxTe or MCT) is the premier material for infrared detection. However, despite its importance, studies exploring the ultrafast photoresponse in this semiconductor alloy are limited. Here, we use time-resolved terahertz spectroscopy to perform a detailed study of the picosecond charge carrier dynamics in long-wave infrared Hg1−xCdxTe (x ∼ 0.2) films, providing insight into ultrafast carrier cooling and temperature-dependent scattering mechanisms. Due to the multilayer photoexcited sample geometry, an elementary thin-film analysis leads to a negative photoconductivity artifact. We, therefore, derive a modified thin-film photoconductivity formula to accurately extract a Drude photoconductivity spectrum. In our analysis, we include the effects of carrier diffusion and the conduction band non-parabolicity in Hg1−xCdxTe. We extract ultrahigh electron mobilities as large as 6 × 105 cm2 V−1 s−1 at 25 K. At cryogenic temperatures, we find the photoexcited electron mobility is up to four times larger than the dark mobility, which we attribute to suppression of ionized impurity scattering due to hole capture by acceptor-type Hg vacancies. In addition, after photoexcitation, we observe a relatively slow rise in photoconductivity over a 10 ps timescale with a monotonically increasing carrier scattering time and a carrier effective mass that decays exponentially with a time constant of 1.9 ps, which we attribute to hot-carrier cooling dynamics in the non-parabolic conduction band.http://dx.doi.org/10.1063/5.0235571 |
| spellingShingle | N. B. Refvik D. N. Purschke C. E. Jensen W. Pan H. R. J. Simpson W. Lei R. Gu J. Antoszewski G. A. Umana-Membreno L. Faraone F. A. Hegmann Ultrafast photoconductivity dynamics in narrow-gap HgCdTe films APL Materials |
| title | Ultrafast photoconductivity dynamics in narrow-gap HgCdTe films |
| title_full | Ultrafast photoconductivity dynamics in narrow-gap HgCdTe films |
| title_fullStr | Ultrafast photoconductivity dynamics in narrow-gap HgCdTe films |
| title_full_unstemmed | Ultrafast photoconductivity dynamics in narrow-gap HgCdTe films |
| title_short | Ultrafast photoconductivity dynamics in narrow-gap HgCdTe films |
| title_sort | ultrafast photoconductivity dynamics in narrow gap hgcdte films |
| url | http://dx.doi.org/10.1063/5.0235571 |
| work_keys_str_mv | AT nbrefvik ultrafastphotoconductivitydynamicsinnarrowgaphgcdtefilms AT dnpurschke ultrafastphotoconductivitydynamicsinnarrowgaphgcdtefilms AT cejensen ultrafastphotoconductivitydynamicsinnarrowgaphgcdtefilms AT wpan ultrafastphotoconductivitydynamicsinnarrowgaphgcdtefilms AT hrjsimpson ultrafastphotoconductivitydynamicsinnarrowgaphgcdtefilms AT wlei ultrafastphotoconductivitydynamicsinnarrowgaphgcdtefilms AT rgu ultrafastphotoconductivitydynamicsinnarrowgaphgcdtefilms AT jantoszewski ultrafastphotoconductivitydynamicsinnarrowgaphgcdtefilms AT gaumanamembreno ultrafastphotoconductivitydynamicsinnarrowgaphgcdtefilms AT lfaraone ultrafastphotoconductivitydynamicsinnarrowgaphgcdtefilms AT fahegmann ultrafastphotoconductivitydynamicsinnarrowgaphgcdtefilms |