Graphene‐Skeleton Heat‐Coordinated and Nanoamorphous‐Surface‐State Controlled Pseudo‐Negative‐Photoconductivity of Tiny SnO<sub>2</sub> Nanoparticles

Ding, Long; Liu, Nishuang; Li, Luying; Wei, Xing; Zhang, Xianghui; Su, Jun; Rao, Jing; Yang, Chunliang; Li, Wenzhi; Wang, Jianbo; Gu, Haoshuang; Gao, Yihua

doi:10.1002/adma.201500804

Cited by 43 publications

(28 citation statements)

References 29 publications

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“…The value of the Seebeck coefficient (4.43 ± 0.26 mV/K) obtained for our copper selenide sample is 10 2 times larger than the Seebeck coefficients (tens of μV/K) of 2D materials. 19,20 Rise and decay portions of Δ V z versus time curves are fitted (Figure 4e, solid lines) using equations and , respectively, where (Δ V z ) max is the maximum value of the potential gradient produced at a given bias voltage and τ dep and τ res are time constants for carrier depletion from and carrier restoration into the channel region, respectively. Time constants (response times) for carrier depletion from the channel region are ∼1.2, ∼0.95, and ∼0.76 s for bias voltages of 0.4, 0.5, and 0.6 V, respectively, while carrier restoration (recovery times) times in the channel region are ∼0.99 s for all bias voltages.…”

Section: Resultsmentioning

confidence: 99%

Photothermal and Joule-Heating-Induced Negative-Photoconductivity-Based Ultraresponsive and Near-Zero-Biased Copper Selenide Photodetectors

Singh

Peng

Rutledge

2019

ACS Appl. Electron. Mater.

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The development of a highly responsive, near-zero-biased broadband photo and thermal detector is required for self-powered night vision security, imaging, remote sensing, and space applications. Photothermal-effect-based photodetectors operate on the principle of photothermal heating and can sense radiation from the UV to IR spectral region for broadband photo and thermal detection. This type of photodetector is highly desirable, but few materials have been shown to meet the stringent requirements including broadband optical/thermal absorption with high absorption coefficients, low thermal conductivity, and a large Seebeck coefficient. Here, we demonstrate ultraresponsive, near-zero-biased photodetectors made of mass-producible Cu 2± x Se nanomaterials. Our photodetectors are fabricated with powder pressing and operate on the principle of negative photoconductivity that utilizes the Seebeck effect under the combined effects of Joule and photothermal heating to detect extremely low levels of broadband optical radiation. We show that copper-deficient Cu 1.8 Se and selenium-deficient Cu 2.5 Se copper selenide materials have negative photoconductivity. However, stochiometric Cu 2 Se copper selenide shows positive photoconductivity. We demonstrate that a photodetector made from the Ag:n + -Cu 1.8 Se:p-Ag:n + system has the best photoresponse and generates a 520 mA/mm negative photocurrent and a high responsivity of 621 A/W under low bias.

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Section: Resultsmentioning

confidence: 99%

Photothermal and Joule-Heating-Induced Negative-Photoconductivity-Based Ultraresponsive and Near-Zero-Biased Copper Selenide Photodetectors

Singh

Peng

Rutledge

2019

ACS Appl. Electron. Mater.

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“…Electronic transmission mechanisms and photocurrent property of photoconductivity of dipeptides have not been well explored. To date, NPC effects have been reported in a variety of materials ranging from simple low-dimensional nanomaterials (graphene quantum dots, 41 InN nanowire, 42 SnO 2 nanoparticles, 43 and MoS 2 single layer 44 ) to various complex crystal structures (γ-glycine, 45 potassium pentaborate, 46 and KCl-doped sulfamic acid 47 ). The decrease in current was explained by the reduction of carrier density or mobility by light-assisted hot electron trapping and carrier scattering.…”

Section: ■ Discussionmentioning

confidence: 99%

Self-Assembled Peptide Nanofibers with Voltage-Regulated Inverse Photoconductance

Shi

et al. 2020

ACS Appl. Mater. Interfaces

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Inverse photoconductance is an uncommon phenomenon observed in selective low-dimensional materials, in which the electrical conductivity of the materials decreases under light illumination. The unique material property holds great promise for biomedical applications in photodetectors, photoelectric logic gates, and low-power nonvolatile memory, which remains a daunting challenge. Especially, tunable photoconductivity for biocompatible materials is highly desired for interfacing with biological systems but is less explored in organic materials. Here, we report nanofibers self-assembled with cyclo-tyrosine-tyrosine (cyclo-YY) having voltage-regulated inverse photoconductance and photoconductance. The peptide nanofibers can be switched back and forth by a bias voltage for imitating biological sensing in artificial vision and memory devices. A peptide optoelectronic resistive random access memory (PORRAM) device has also been fabricated using the nanofibers that can be electrically switched between long-term and short-term memory. The underlying mechanism of the reversible photoconductance is discussed in this paper. Due to the inherent biocompatibility of peptide materials, the reversible photoconductive nanofibers may have broad applications in sensing and storage for biotic and abiotic interfaces.

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“…NPC has been observed in semiconducting nanostructures by localized trapped states 18 , band gap opening in topological insulators 16 , e-SPPs scattering in metallic nanowires 17, 33 , adsorbent molecule in graphene based composite systems 34 , doping-induced formation of trions in MoS 2 35 etc. Here we address the origin of the observed NPC by calculating the dc resistivity from Drude’s free electron model which deals with various scattering mechanisms experienced by conduction electrons while travelling under an electric field in the presence of light.…”

Section: Discussionmentioning

confidence: 99%

Light Induced Electron-Phonon Scattering Mediated Resistive Switching in Nanostructured Nb Thin Film Superconductor

Sharma

Yadav

Gajar

et al. 2017

Sci Rep

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The elemental Nb is mainly investigated for its eminent superconducting properties. In contrary, we report of a relatively unexplored property, namely, its superior optoelectronic property in reduced dimension. We demonstrate here that nanostructured Nb thin films (NNFs), under optical illumination, behave as room temperature photo-switches and exhibit bolometric features below its superconducting critical temperature. Both photo-switch and superconducting bolometric behavior are monitored by its resistance change with light in visible and near infrared (NIR) wavelength range. Unlike the conventional photodetectors, the NNF devices switch to higher resistive states with light and the corresponding resistivity change is studied with thickness and grain size variations. At low temperature in its superconducting state, the light exposure shifts the superconducting transition towards lower temperature. The room temperature photon sensing nature of the NNF is explained by the photon assisted electron-phonon scattering mechanism while the low temperature light response is mainly related to the heat generation which essentially changes the effective temperature for the device and the device is capable of sensing a temperature difference of few tens of milli-kelvins. The observed photo-response on the transport properties of NNFs can be very important for future superconducting photon detectors, bolometers and phase slip based device applications.The refractory metal Nb is famous for its superconducting properties and it is known to provide the highest critical temperature (T c ) (bulk T c = 9.2 K) for any elemental superconductor. Being one of the most used primary superconductors, Nb is well explored material in the field of superconducting photon detectors 1, 2 and bolometric applications 3 . Besides, it exhibits various physical properties like high melting point, high thermal conductivity, high critical current density etc 4 . Since decades, dimensional effects of niobium on its physical properties like critical temperature, superconducting energy gap, critical field, coherence length, penetration depth etc. have been explored. These properties vary with the dimension of niobium particles/grains and/or films 5 . It is well known that nanomaterials can exist as various nanostructures such as quantum dots, nanowires, nanoparticles, etc. which play key role in upgrading their optoelectronic properties, mainly controlled by the quantum effect, as compared to their bulk counterpart 6,7 . For example, granular Nb thin films have been shown to act like Josephson junctions 5,8 . During 1970's the effects of light on conventional superconductors have been explored intensely 9 . The effect of light and transient photo-response on oxide based high-T c superconductors have also garnered a reasonable attention in the field of superconductivity based optoelectronic applications 10 . Here, we explore optoelectronic properties of NNFs at room temperature (RT) and at low temperature (LT), above and below the T c . To the best of ou...

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Graphene‐Skeleton Heat‐Coordinated and Nanoamorphous‐Surface‐State Controlled Pseudo‐Negative‐Photoconductivity of Tiny SnO₂ Nanoparticles

Cited by 43 publications

References 29 publications

Photothermal and Joule-Heating-Induced Negative-Photoconductivity-Based Ultraresponsive and Near-Zero-Biased Copper Selenide Photodetectors

Photothermal and Joule-Heating-Induced Negative-Photoconductivity-Based Ultraresponsive and Near-Zero-Biased Copper Selenide Photodetectors

Self-Assembled Peptide Nanofibers with Voltage-Regulated Inverse Photoconductance

Light Induced Electron-Phonon Scattering Mediated Resistive Switching in Nanostructured Nb Thin Film Superconductor

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Graphene‐Skeleton Heat‐Coordinated and Nanoamorphous‐Surface‐State Controlled Pseudo‐Negative‐Photoconductivity of Tiny SnO2 Nanoparticles

Cited by 43 publications

References 29 publications

Photothermal and Joule-Heating-Induced Negative-Photoconductivity-Based Ultraresponsive and Near-Zero-Biased Copper Selenide Photodetectors

Photothermal and Joule-Heating-Induced Negative-Photoconductivity-Based Ultraresponsive and Near-Zero-Biased Copper Selenide Photodetectors

Self-Assembled Peptide Nanofibers with Voltage-Regulated Inverse Photoconductance

Light Induced Electron-Phonon Scattering Mediated Resistive Switching in Nanostructured Nb Thin Film Superconductor

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Graphene‐Skeleton Heat‐Coordinated and Nanoamorphous‐Surface‐State Controlled Pseudo‐Negative‐Photoconductivity of Tiny SnO₂ Nanoparticles