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Rippled Metallic‐Nanowire/Graphene/Semiconductor Nanostack for a Gate‐Tunable Ultrahigh‐Performance Stretchable Phototransistor

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Abstract and Figures

Despite being one of the most robust materials with intriguing optoelectronic properties, the practical use of single‐layer graphene (SLG) in soft‐electronic technologies is limited due to its poor native stretchability, low absorption coefficient, poor on/off ratio, etc. To circumvent these difficulties, here, a rippled gate‐tunable ultrahigh responsivity nanostack phototransistor composed of SLG, semiconductor‐nanoparticles (NPs), and metallic‐nanowires (NWs) embedded in an elastic film is proposed. The unique electronic conductivity of SLG and high absorption strength of semiconductor‐NPs produce an ultrahigh photocurrent gain. The metallic NWs serve as an excellent stretchable gate electrode. The ripple structured nanomaterials surmount their native stretchability, providing strength and electromechanical stability to the composite. Combining all these unique features, highly stretchable and ultrasensitive phototransistors are created, which can be stretched up to 30% with high repeatability maintaining a photoresponsivity, photocurrent gain, and detectivity of ≈10⁶ A W⁻¹, 10⁷, and 10¹³ Jones, respectively, which are comparable with the same class of rigid devices. In addition, the device can be turned‐off by applying a suitable gate voltage, which is very convenient for photonic circuits. Moreover, the study can be extended to many other 2D systems, and therefore paves a crucial step for designing high‐performance soft optoelectronic devices for practical applications.
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2000859 (1 of 10) © 2020 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim
www.advopticalmat.de
Full PaPer
Rippled Metallic-Nanowire/Graphene/Semiconductor
Nanostack for a Gate-Tunable Ultrahigh-Performance
Stretchable Phototransistor
Golam Haider, Yen-Hsiang Wang, Farjana J. Sonia, Chia-Wei Chiang, Otakar Frank,
Jana Vejpravova, Martin Kalbáč,* and Yang-Fang Chen*
DOI: 10.1002/adom.202000859
1. Introduction
Stretchable, flexible, and foldable elec-
tronics have recently attracted much atten-
tion due to its transformative impact in a
multitude of domains, including wearable
human–machine interacting devices, com-
puters, sensors, electronic textiles, and
biomedical devices for health and envi-
ronmental monitoring as well as many
other not-yet-realized systems.[1–8] For
high-performance stretchable devices, the
constituent materials should simultane-
ously exhibit excellent optical and elec-
trical properties as well as mechanical
robustness, which are not easy to achieve.
The development of stretchable devices
encountered many diculties in finding
suitable materials that are mechanically
compliant and solution-processable.[2,4,7–11]
With great eorts and intensive studies,
several stretchable devices, including sen-
sors, light-emitting diodes, solar cells,
lasers, transistors, and photodetectors
have been reported recently.[4–6,12–22] How-
ever, there exists a huge lag of current
demand and device performance that
needs to be addressed.[25–27] For instance,
phototransistors are one of the most fun-
damental building blocks of modern-day electronics. However,
reports on high-performance stretchable phototransistors are
rare; the development of stretchable phototransistors is thus
highly desirable and intriguing. To compete with the state-of-
the-art technology, devices are required to have capabilities
of bending, twisting, stretching into complex shapes while
maintaining high performance and reliability.[10,11,18,19,26,28] A
composite material with ultrahigh mobility, very strong photon
absorption strength together with a very high mechanical
robustness against deformation is essential. Along this direc-
tion, recently discovered graphene has shown huge potential to
accommodate such functionalities, i.e., single-layer graphene
(SLG) is thinnest, ultrastrong, mechanically deformable mate-
rial showing surprisingly high carrier mobility and ultrabroad-
band absorption capability making it an ideal choice.[29,30]
However, the absorption strength of SLG is surprisingly low,
which shows a photoresponsivity of 102 A W1. In addition,
Despite being one of the most robust materials with intriguing opto-
electronic properties, the practical use of single-layer graphene (SLG) in
soft-electronic technologies is limited due to its poor native stretchability,
low absorption coecient, poor on/o ratio, etc. To circumvent these
diculties, here, a rippled gate-tunable ultrahigh responsivity nanostack
phototransistor composed of SLG, semiconductor-nanoparticles (NPs),
and metallic-nanowires (NWs) embedded in an elastic film is proposed.
The unique electronic conductivity of SLG and high absorption strength of
semiconductor-NPs produce an ultrahigh photocurrent gain. The metallic
NWs serve as an excellent stretchable gate electrode. The ripple structured
nanomaterials surmount their native stretchability, providing strength and
electromechanical stability to the composite. Combining all these unique
features, highly stretchable and ultrasensitive phototransistors are created,
which can be stretched up to 30% with high repeatability maintaining a
photoresponsivity, photocurrent gain, and detectivity of 106 A W1, 107, and
1013 Jones, respectively, which are comparable with the same class of rigid
devices. In addition, the device can be turned-o by applying a suitable gate
voltage, which is very convenient for photonic circuits. Moreover, the study
can be extended to many other 2D systems, and therefore paves a crucial
step for designing high-performance soft optoelectronic devices for prac-
tical applications.
Dr. G. Haider, Dr. F. J. Sonia, Dr. O. Frank, Dr. M. Kalbáč
Nanocarbon Group
J. Heyrovsky Institute of Physical Chemistry
Dolejškova 2155, Prague 182 23, Czech Republic
E-mail: martin.kalbac@jh-inst.cas.cz
Y.-H. Wang, C.-W. Chiang, Prof. Y.-F. Chen
Department of Physics
National Taiwan University
No. 1, Sec. 4, Roosevelt Road, Taipei 106, Taiwan, Republic of China
E-mail: yfchen@phys.ntu.edu.tw
Prof. J. Vejpravova
Department of Condensed Matter Physics
Faculty of Mathematics and Physics
Charles University
Ke Karlovu 5, Prague 121 16, Czech Republic
The ORCID identification number(s) for the author(s) of this article
can be found under https://doi.org/10.1002/adom.202000859.
Adv. Optical Mater. 2020, 8, 2000859
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... However, it is known that in ambient conditions, physisorbed gas molecules [64] in single layer graphene efficiently release from the layer under those high energy excitations, which as a result increases the n doping in the EG layer, see Fig. 4(b) [59,[65][66][67] and a positive photocurrent. Note that releasing such adsorbed gases is much slower than the interlayer charge transfer time scale [59,67]. Thus, the transient photocurrent response is found to be slower. ...
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