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Dark Current Analysis on GeSn p-i-n Photodetectors

Group IV alloys of GeSn have been extensively investigated as a competing material alternative in shortwave-to-mid-infrared photodetectors (PDs). The relatively large defect densities present in GeSn alloys are the major challenge in developing practical devices, owing to the low-temperature growth...

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Autores principales: Ghosh, Soumava, Sun, Greg, Morgan, Timothy A., Forcherio, Gregory T., Cheng, Hung-Hsiang, Chang, Guo-En
Formato: Online Artículo Texto
Lenguaje:English
Publicado: MDPI 2023
Materias:
Acceso en línea:https://www.ncbi.nlm.nih.gov/pmc/articles/PMC10490798/
https://www.ncbi.nlm.nih.gov/pubmed/37687985
http://dx.doi.org/10.3390/s23177531
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author Ghosh, Soumava
Sun, Greg
Morgan, Timothy A.
Forcherio, Gregory T.
Cheng, Hung-Hsiang
Chang, Guo-En
author_facet Ghosh, Soumava
Sun, Greg
Morgan, Timothy A.
Forcherio, Gregory T.
Cheng, Hung-Hsiang
Chang, Guo-En
author_sort Ghosh, Soumava
collection PubMed
description Group IV alloys of GeSn have been extensively investigated as a competing material alternative in shortwave-to-mid-infrared photodetectors (PDs). The relatively large defect densities present in GeSn alloys are the major challenge in developing practical devices, owing to the low-temperature growth and lattice mismatch with Si or Ge substrates. In this paper, we comprehensively analyze the impact of defects on the performance of GeSn p-i-n homojunction PDs. We first present our theoretical models to calculate various contributing components of the dark current, including minority carrier diffusion in p- and n-regions, carrier generation–recombination in the active intrinsic region, and the tunneling effect. We then analyze the effect of defect density in the GeSn active region on carrier mobilities, scattering times, and the dark current. A higher defect density increases the dark current, resulting in a reduction in the detectivity of GeSn p-i-n PDs. In addition, at low Sn concentrations, defect-related dark current density is dominant, while the generation dark current becomes dominant at a higher Sn content. These results point to the importance of minimizing defect densities in the GeSn material growth and device processing, particularly for higher Sn compositions necessary to expand the cutoff wavelength to mid- and long-wave infrared regime. Moreover, a comparative study indicates that further improvement of the material quality and optimization of device structure reduces the dark current and thereby increases the detectivity. This study provides more realistic expectations and guidelines for evaluating GeSn p-i-n PDs as a competitor to the III-V- and II-VI-based infrared PDs currently on the commercial market.
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spelling pubmed-104907982023-09-09 Dark Current Analysis on GeSn p-i-n Photodetectors Ghosh, Soumava Sun, Greg Morgan, Timothy A. Forcherio, Gregory T. Cheng, Hung-Hsiang Chang, Guo-En Sensors (Basel) Article Group IV alloys of GeSn have been extensively investigated as a competing material alternative in shortwave-to-mid-infrared photodetectors (PDs). The relatively large defect densities present in GeSn alloys are the major challenge in developing practical devices, owing to the low-temperature growth and lattice mismatch with Si or Ge substrates. In this paper, we comprehensively analyze the impact of defects on the performance of GeSn p-i-n homojunction PDs. We first present our theoretical models to calculate various contributing components of the dark current, including minority carrier diffusion in p- and n-regions, carrier generation–recombination in the active intrinsic region, and the tunneling effect. We then analyze the effect of defect density in the GeSn active region on carrier mobilities, scattering times, and the dark current. A higher defect density increases the dark current, resulting in a reduction in the detectivity of GeSn p-i-n PDs. In addition, at low Sn concentrations, defect-related dark current density is dominant, while the generation dark current becomes dominant at a higher Sn content. These results point to the importance of minimizing defect densities in the GeSn material growth and device processing, particularly for higher Sn compositions necessary to expand the cutoff wavelength to mid- and long-wave infrared regime. Moreover, a comparative study indicates that further improvement of the material quality and optimization of device structure reduces the dark current and thereby increases the detectivity. This study provides more realistic expectations and guidelines for evaluating GeSn p-i-n PDs as a competitor to the III-V- and II-VI-based infrared PDs currently on the commercial market. MDPI 2023-08-30 /pmc/articles/PMC10490798/ /pubmed/37687985 http://dx.doi.org/10.3390/s23177531 Text en © 2023 by the authors. https://creativecommons.org/licenses/by/4.0/Licensee MDPI, Basel, Switzerland. This article is an open access article distributed under the terms and conditions of the Creative Commons Attribution (CC BY) license (https://creativecommons.org/licenses/by/4.0/).
spellingShingle Article
Ghosh, Soumava
Sun, Greg
Morgan, Timothy A.
Forcherio, Gregory T.
Cheng, Hung-Hsiang
Chang, Guo-En
Dark Current Analysis on GeSn p-i-n Photodetectors
title Dark Current Analysis on GeSn p-i-n Photodetectors
title_full Dark Current Analysis on GeSn p-i-n Photodetectors
title_fullStr Dark Current Analysis on GeSn p-i-n Photodetectors
title_full_unstemmed Dark Current Analysis on GeSn p-i-n Photodetectors
title_short Dark Current Analysis on GeSn p-i-n Photodetectors
title_sort dark current analysis on gesn p-i-n photodetectors
topic Article
url https://www.ncbi.nlm.nih.gov/pmc/articles/PMC10490798/
https://www.ncbi.nlm.nih.gov/pubmed/37687985
http://dx.doi.org/10.3390/s23177531
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