Flexible titanium nitride/germanium-tin photodetectors based on sub-bandgap absorption

We report an enhanced performance of flexible titanium nitride/germanium-tin (TiN/GeSn) photodetectors (PDs) with an extended photodetection range based on sub-bandgap absorption. Single-crystalline GeSn membranes transfer-printed on poly(ethylene terephthalate) are integrated with plasmonic TiN to...

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Main Authors: An, Shu, Liao, Yikai, Kim, Munho
Other Authors: School of Electrical and Electronic Engineering
Format: Article
Language:English
Published: 2022
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Online Access:https://hdl.handle.net/10356/156825
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Institution: Nanyang Technological University
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spelling sg-ntu-dr.10356-1568252022-05-01T02:53:23Z Flexible titanium nitride/germanium-tin photodetectors based on sub-bandgap absorption An, Shu Liao, Yikai Kim, Munho School of Electrical and Electronic Engineering Engineering::Electrical and electronic engineering::Semiconductors Flexible Photodetector Sub-Bandgap We report an enhanced performance of flexible titanium nitride/germanium-tin (TiN/GeSn) photodetectors (PDs) with an extended photodetection range based on sub-bandgap absorption. Single-crystalline GeSn membranes transfer-printed on poly(ethylene terephthalate) are integrated with plasmonic TiN to form a TiN/GeSn heterojunction. Formation of the heterojunction creates a Schottky contact between the TiN and GeSn. A Schottky barrier height of 0.49 eV extends the photodetection wavelength to 2530 nm and further enhances the light absorption capability within the detection range. In addition, finite-difference time-domain simulation proves that the integration of TiN and GeSn could enhance average absorption from 0.13 to 0.33 in the near-infrared (NIR) region (e.g., 1400-2000 nm) and more than 70% of light is absorbed in TiN. The responsivity of the fabricated TiN/GeSn PDs is increased from 30 to 148.5 mA W-1 at 1550 nm. There is also an ∼180 nm extension in the optical absorption wavelength of the flexible TiN/GeSn PD. The enhanced performance of the device is attributed to the absorption and separation of plasmonic hot carriers via TiN and the TiN/GeSn junction, respectively. The effect of external uniaxial strain is also investigated. A tensile strain of 0.3% could further increase the responsivity from 148.5 to 218 mA W-1, while it is decreased to 102 mA W-1 by 0.25% compressive strain. In addition, the devices maintain stable performance after multiple and long bending cycles. Our results provide a robust and cost-effective method to extend the NIR photodetection capability of flexible group IV PDs. Agency for Science, Technology and Research (A*STAR) Ministry of Education (MOE) Submitted/Accepted version This work was supported by the A∗STAR, Singapore, Advanced Manufacturing and Engineering (AME) Young Individual Research Grant (YIRG) under the Project A2084c0066 and Ministry of Education, Singapore, under the Grant ACRF Tier 2 grant (T2EP50120-0003). Authors acknowledge Xiao Gong at National University of Singapore and Bongkwon Son and Chuan Seng Tan at Nanyang Technological University for their technical support. Authors also acknowledge the support of Nanyang NanoFabrication Centre (N2FC). 2022-04-26T01:17:46Z 2022-04-26T01:17:46Z 2021 Journal Article An, S., Liao, Y. & Kim, M. (2021). Flexible titanium nitride/germanium-tin photodetectors based on sub-bandgap absorption. ACS Applied Materials & Interfaces, 13(51), 61396-61403. https://dx.doi.org/10.1021/acsami.1c15181 1944-8244 https://hdl.handle.net/10356/156825 10.1021/acsami.1c15181 34851080 2-s2.0-85120862326 51 13 61396 61403 en A2084c0066 T2EP50120-0003 ACS Applied Materials & Interfaces This document is the Accepted Manuscript version of a Published Work that appeared in final form in ACS Applied Materials & Interfaces, copyright © American Chemical Society after peer review and technical editing by the publisher. To access the final edited and published work see https://doi.org/10.1021/acsami.1c15181. application/pdf
institution Nanyang Technological University
building NTU Library
continent Asia
country Singapore
Singapore
content_provider NTU Library
collection DR-NTU
language English
topic Engineering::Electrical and electronic engineering::Semiconductors
Flexible Photodetector
Sub-Bandgap
spellingShingle Engineering::Electrical and electronic engineering::Semiconductors
Flexible Photodetector
Sub-Bandgap
An, Shu
Liao, Yikai
Kim, Munho
Flexible titanium nitride/germanium-tin photodetectors based on sub-bandgap absorption
description We report an enhanced performance of flexible titanium nitride/germanium-tin (TiN/GeSn) photodetectors (PDs) with an extended photodetection range based on sub-bandgap absorption. Single-crystalline GeSn membranes transfer-printed on poly(ethylene terephthalate) are integrated with plasmonic TiN to form a TiN/GeSn heterojunction. Formation of the heterojunction creates a Schottky contact between the TiN and GeSn. A Schottky barrier height of 0.49 eV extends the photodetection wavelength to 2530 nm and further enhances the light absorption capability within the detection range. In addition, finite-difference time-domain simulation proves that the integration of TiN and GeSn could enhance average absorption from 0.13 to 0.33 in the near-infrared (NIR) region (e.g., 1400-2000 nm) and more than 70% of light is absorbed in TiN. The responsivity of the fabricated TiN/GeSn PDs is increased from 30 to 148.5 mA W-1 at 1550 nm. There is also an ∼180 nm extension in the optical absorption wavelength of the flexible TiN/GeSn PD. The enhanced performance of the device is attributed to the absorption and separation of plasmonic hot carriers via TiN and the TiN/GeSn junction, respectively. The effect of external uniaxial strain is also investigated. A tensile strain of 0.3% could further increase the responsivity from 148.5 to 218 mA W-1, while it is decreased to 102 mA W-1 by 0.25% compressive strain. In addition, the devices maintain stable performance after multiple and long bending cycles. Our results provide a robust and cost-effective method to extend the NIR photodetection capability of flexible group IV PDs.
author2 School of Electrical and Electronic Engineering
author_facet School of Electrical and Electronic Engineering
An, Shu
Liao, Yikai
Kim, Munho
format Article
author An, Shu
Liao, Yikai
Kim, Munho
author_sort An, Shu
title Flexible titanium nitride/germanium-tin photodetectors based on sub-bandgap absorption
title_short Flexible titanium nitride/germanium-tin photodetectors based on sub-bandgap absorption
title_full Flexible titanium nitride/germanium-tin photodetectors based on sub-bandgap absorption
title_fullStr Flexible titanium nitride/germanium-tin photodetectors based on sub-bandgap absorption
title_full_unstemmed Flexible titanium nitride/germanium-tin photodetectors based on sub-bandgap absorption
title_sort flexible titanium nitride/germanium-tin photodetectors based on sub-bandgap absorption
publishDate 2022
url https://hdl.handle.net/10356/156825
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