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Large-scale and heterogeneous integration of NWs for image sensing. (A) Optical image of an array of all-nanowire photodetector circuitry with each circuit element serving as an independently addressable pixel. (B) A defect analysis map showing the functional and defective NW photodetector circuit elements. (C) A histogram of the photocurrent for all functional circuit elements of the fabricated array. (D) An output response of the circuit array, imaging a circular light spot. The contrast represents the normalized photocurrent, with the gray pixels representing the defective sites (see SI Text).
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We report large-scale integration of nanowires for heterogeneous, multifunctional circuitry that utilizes both the sensory and electronic functionalities of single crystalline nanomaterials. Highly ordered and parallel arrays of optically active CdSe nanowires and high-mobility Ge/Si nanowires are deterministically positioned on substrates, and con...
Contexts in source publication
Context 1
... NW FETs were found nonresponsive to white light illumination which guaranteed no undesired interference (see Fig. S4). For the circuit level operation, the operating bias, V DD was maintained at 3V for all measurements. The gate electrode for T1 was biased at V G1 3V (corresponding to R T1 1-2 G) to match the output impedance of the CdSe NS. The output signal of a circuit for multiple white light illumination cycles (4.4 mW/cm 2 ) is depicted in Fig. ...
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... further demonstrate the versatility of our approach, we fabricated large arrays (i.e., 13 20) of the all-nanowire circuits on a chip (Fig. 4A), and measured the photoresponse of each individual circuit element. Rather than single CdSe NWs, par- allel arrays of 5-10 NWs were used as the active element of each NS to enhance the yield and reduce the variation by taking advantage of the averaging effect (see Fig. S6). It was found that 80% of the circuits demonstrated successful ...
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... element. Rather than single CdSe NWs, par- allel arrays of 5-10 NWs were used as the active element of each NS to enhance the yield and reduce the variation by taking advantage of the averaging effect (see Fig. S6). It was found that 80% of the circuits demonstrated successful photoresponse operation as depicted in the failure analysis map (Fig. 4B). The functional circuits exhibited a mean photocurrent of 420 A with a standard deviation of 165 A. The reasonably small circuit-to-circuit variation arises from the uniformity of the assembled nanowire arrays. The three major causes for circuit failure were (i) fabrication defects (i.e., poor metal lift-off and gate dielectric ...
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... for each individual working circuit and digitized into a 0-100 scale with ''0'' and ''100'' representing the maximum and minimum mea- sured intensity, respectively (see SI Text). Each of the circuits was regarded as a pixel and the measured intensity levels of the circuits were incorporated into a 2D plot to generate a contrast map shown in Fig. 4D. The contrast map clearly demonstrates the spatial intensity variation from the center to the outer edge of the circuit matrix, precisely matching the intensity profile of the projected light source, thus showing a preliminary imaging function with an all-nanowire circuit array. In future, significant downscaling of the pixel size can ...
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Nanoelectronic devices based on 2D materials are far from delivering their full theoretical performance potential due to the lack of scalable insulators. Amorphous oxides that work well in silicon technology have ill-defined interfaces with 2D materials and numerous defects, while 2D hexagonal boron nitride does not meet required dielectric specifi...
Citations
... The rapid advancement in high-resolution fabrication and transfer of nanoscale functional structures is driven by the demand for superior mechanical robustness and reliability, large-area uniformity, fast processing rates, all-dry processing conditions, low manufacturing costs, and crucially, conformal integration onto arbitrary substrates, including flexible, stretchable, and curvilinear surfaces, without compromising performance [1][2][3][4][5][6][7][8][9]. This demand is driven by the fastgrowing need for unconventional form factors in broad applications, including artificial skin [1], brain/machine interfaces [2], rollable and full-color displays [5,10], three-dimensional (3D)-stacked multilayer functional nanostructures, and heterodevices [11][12][13][14][15]. ...
To meet the fast-growing need for broad applications in nanoelectronics, nanophotonics, and flexible optoelectronics, novel processes that can integrate different functional nanostructures onto specific substrates are urgently desired. Existing direct-lithography methods are difficult to use on flexible, nonplanar, and biocompatible surfaces. Therefore, fabrication is usually accomplished by nanotransfer printing. However, large-scale integration of multiscale nanostructures on unconventional substrates is challenging because the fabrication yield and quality are often limited by the resolution, uniformity, adhesivity, and integrity of the nanostructures formed via direct transfer. We propose a resist-based transfer strategy enabled by near-zero adhesion, which we achieved by molecular modification to attain a critical surface energy interval. This approach enabled the intact transfer of wafer-scale, ultrathin-resist nanofilms onto arbitrary substrates with mitigated cracking and wrinkling, thereby facilitating the in-situ fabrication of nanostructures for functional devices. Based on this approach, 3D-stacked multilayer structures with enhanced functionalities, nanoplasmonic structures with ~10-nm resolution, and MoS2-based devices with excellent performance were demonstrated on specific substrates. Collectively, this demonstrated the high stability, reliability, and throughput of our strategy for optical and electronic-device applications.
... T HE advancement in the microelectronics industries has seen exponential growth in sensing technology. In earlier times, when sensing technology was not popularized, the industries mostly developed sensing systems with large-scale integrated systems [1]- [3]. In the late 90s, semiconducting sensors were preferred due to their linear operating range, large temperature and humidity range, easy interfacing with control systems, robustness and fast response. ...
The importance of wearable sensors has constantly increased in the current era of smart wearable sensors. Among the carbon-based allotropes used to form the sensors, carbon fibers (CFs) have been very popular due to their low weight, excellent electrical, mechanical and thermal characteristics. The paper presents some of the significant work done on using carbon fibers to form composites-based wearable sensors. These composites were developed by mixing carbon fibers and various polymers at optimized ratios via certain fabrication techniques, including printing, layer-by-layer and self-assembling techniques. A classification of the highlighted research has been done based on three categories. The first two types include the polymer types formed using silicone. Polydimethylsiloxane (PDMS) and silicone rubber are the major categories used to form composites with carbon fibers. This is due to their homogenous mixing, hydrophobicity and biocompatibility. The third category consists of other types of polymers used to form these hybrid prototypes. Finally, some of the challenges existing with the current carbon fiber/polymer-based composites have been mentioned and their possible remedies.
... Therefore, the performance of the individual WS 2 -based photodetectors is generally limited [9][10][11]. In addition, modern optoelectronic applications increasingly require polarization-dependent photodetection [12][13][14], which cannot be achieved by 2D WS 2 . ...
The widespread application of photodetectors
has triggered an urgent need for high-sensitivity and polarization-dependent photodetection. In this field, the two-dimensional (2D) tungsten disulfide (WS2) exhibits intriguing
optical and electronic properties, making it an attractive
photosensitive material for optoelectronic applications.
However, the lack of an effective built-in electric field and
photoconductive gain mechanism in 2D WS2 impedes its application in high-performance photodetectors. Herein, we
propose a hybrid heterostructure photodetector that contains
1D Te and 2D WS2. In this device, 1D Te induces in-plane
strain in 2D WS2, which regulates the electronic structures of
local WS2 and gives rise to type-II band alignment in the
horizontal direction. Moreover, the vertical heterojunction
built of 2D WS2 and 1D Te introduces a high photoconductive
gain. Benefiting from these two effects, the transfer of photogenerated carriers is optimized, and the proposed photodetector exhibits high sensitivity (photoresponsivity of
~27.7 A W−1, detectivity of 9.5 × 1012 Jones, and short rise/
decay time of 19.3/17.6 ms). In addition, anisotropic photodetection characteristics with a dichroic ratio up to 2.1 are
achieved. This hybrid 1D/2D heterostructure overcomes the
inherent limitations of each material and realizes novel
properties, opening up a new avenue towards constructing
multifunctional optoelectronic devices.
... O NE-DIMENSIONAL inorganic semiconducting nanomaterials have been extensively explored for high-performance flexible devices, including transistors [1], [2], sensors [3], [4], [5], and energy harvesters [6], [7], [8]. This is because of their exciting physical, optical, and electronic properties, including high excitonic binding energy, excellent charge transport, and high aspect ratio [9], [10], [11]. Accordingly, considerable efforts have been made to develop effective means for integration of nanowires (NWs) on flexible/plastic substrates [12], [13], [14], [15], [16], [17]. ...
... Accordingly, considerable efforts have been made to develop effective means for integration of nanowires (NWs) on flexible/plastic substrates [12], [13], [14], [15], [16], [17]. For example, methods, such as Langmuir-Blodgett (LB) [18], spray coating [19], and float assembly [20], have been used in conjunction with lithography steps to integrate NWs at selective locations (patterning) and various devices from them [9], [10], [11], [12], [13], [21], [22], [23]. Among various NW assembly/integration approaches, contact printing offers unique advantages: 1) highly directional alignment of NWs in a single-step process; 2) costeffectiveness; 3) negligible contamination, as it is a dry printing method; 4) possibility to print different types of NWs including heterostructures with unique electronic/optical properties; and 5) possibility for selective printing of NWs. ...
Patterned assembly of inorganic nanowires (NWs) at desired locations offers the opportunity to realise large-area high performance flexible electronics. Transfer and Contact printing methods are some of the viable methods to achieve this. However, some of the fabrication steps in these methods rely on lithography, which are inherently wasteful and therefore, the approach is not an ideal solution for large area electronics. Herein, we show a lithography-free patterning technique in which NWs are selectively removed from a uniformly contact printed electronic layer. The NWs are removed using an elastomeric stamp. The removal efficiency is improved by evaporating a thin layer of water onto its patterned face, which greatly enhances the stamp-NW adhesion via the capillary action. The SEM analyses of the NW layer showed a good pattern fidelity, fair retention of the initial NW density and optimal contrast between positive and negative areas of the pattern. The efficacy of the presented technique for printed electronics is demonstrated by fabricating all-printed ZnO NW-based photodetectors (PDs) on a flexible substrate. Using the as-prepared patterned NWs, a 3×4 array of PD devices is fabricated. The PDs show good responsivity (1.3×10
<sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">6</sup>
A/W) and specific detectivity (6.95×10
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Jones) in the UV range. These devices show that the presented selective removal approach could be an attractive route for future lithography-free printed electronics.
... Although the concept of contact printing and its variants, such as differential roll printing, have been reported in the past 10,11,[18][19][20][21][22][23][24][25][26][27][28][29][30][31][32] , there is limited information available on the equipment that is used to carry out the process. Often, manual approaches have been employed, such as pressing by hand or using weights 11,18 , whereas in other cases, equipment meant for other uses was repurposed 22 . ...
Printing is a promising method for the large-scale, high-throughput, and low-cost fabrication of electronics. Specifically, the contact printing approach shows great potential for realizing high-performance electronics with aligned quasi-1D materials. Despite being known for more than a decade, reports on a precisely controlled system to carry out contact printing are rare and printed nanowires (NWs) suffer from issues such as location-to-location and batch-to-batch variations. To address this problem, we present here a novel design for a tailor-made contact printing system with highly accurate control of printing parameters (applied force: 0–6 N ± 0.3%, sliding velocity: 0–200 mm/s, sliding distance: 0–100 mm) to enable the uniform printing of nanowires (NWs) aligned along 93% of the large printed area (1 cm ² ). The system employs self-leveling platforms to achieve optimal alignment between substrates, whereas the fully automated process minimizes human-induced variation. The printing dynamics of the developed system are explored on both rigid and flexible substrates. The uniformity in printing is carefully examined by a series of scanning electron microscopy (SEM) images and by fabricating a 5 × 5 array of NW-based photodetectors. This work will pave the way for the future realization of highly uniform, large-area electronics based on printed NWs.
... Towards the practical application of SMO-NWs, the integration of top-down and bottom-up strategies is required to combine their merits. The first all-integrated sensor circuit based on cadmium selenide (CdSe) and germanium/silicon (Ge/Si) NWs was reported by the Javey group in 2008, showing the advantages of combining vapor-phase synthesis, printing and photolithography techniques [121]. Moreover, Marasso et al., combined the top-down and bottom-up strategies by developing a polymeric-mask centrifugation method to deposit ZnO nanostructures on MEMS micro-hotplates [122]. ...
Semiconducting metal oxide-based nanowires (SMO-NWs) for gas sensors have been extensively studied for their extraordinary surface-to-volume ratio, high chemical and thermal stabilities, high sensitivity, and unique electronic, photonic and mechanical properties. In addition to improving the sensor response, vast developments have recently focused on the fundamental sensing mechanism, low power consumption, as well as novel applications. Herein, this review provides a state-of-art overview of electrically transduced gas sensors based on SMO-NWs. We first discuss the advanced synthesis and assembly techniques for high-quality SMO-NWs, the detailed sensor architectures, as well as the important gas-sensing performance. Relationships between the NWs structure and gas sensing performance are established by understanding general sensitization models related to size and shape, crystal defect, doped and loaded additive, and contact parameters. Moreover, major strategies for low-power gas sensors are proposed, including integrating NWs into microhotplates, self-heating operation, and designing room-temperature gas sensors. Emerging application areas of SMO-NWs-based gas sensors in disease diagnosis, environmental engineering, safety and security, flexible and wearable technology have also been studied. In the end, some insights into new challenges and future prospects for commercialization are highlighted.
... 1D nanomaterials have exceptional electronic properties, such as high carrier mobility, excellent switching characteristics, and superior photoelectric effects, which can be designed to fabricate complicated electronic devices including integrated circuits, microsensors, and optoelectronics. [108][109][110][111][112][113][114] Often, 1D nanomaterials are aligned in a uniform direction and form the desired pattern by assembly such as the LS method, contact printing, and self-assembly. Compared to crude random assembly, the superiorities of precise assembly with definite architecture can be briefly summarized as follows: ...
Due to their unique structure, one dimension (1D) nanomaterials have attracted considerable research attentions and shown potential applications in the modern nano-devices. With the advances in chemistry and materials science, integrating these 1D nano-building blocks for macroscopic well-designed assemblies will provide new opportunities for sustainable and advanced applications. This article comprehensively reviews the structure-property relationship of the assembled nanowire materials to distinguish it from the disordered statement. Specifically, we firstly highlight the anisotropy phenomenon of the 1D assemblies, including the anisotropic conductive properties, optical properties, thermal conduction properties, and anisotropy strain sensing. Next, we systematically review the superior properties of order 1D assembly devices compared to random samples to elucidate the advantages of well-defined structures. The programmability of ordered assemblies with predictable architecture for large-scale devices is also briefly commented. Finally, a summary and perspectives on challenges and future opportunities are presented.
... Polyimide was used as the substrate layer while pressure-sensitive rubber was used as the sensing layer. The sensor showed good potential at low voltage operation in addition to high stability [8][9][10]. In another study, Abiri et al. demonstrated the use of silicon nanowire-based biosensors in detecting cancer cells in the lungs due to its good electric signal transduction ability. ...
Perovskite oxides have been used as sensors, actuators, transducers, for sound generation and detection, and also in optical instruments and microscopes. Perovskite halides are currently considered as optoelectronic devices such as solar cells, photodetectors, and radiation detection, but there are major issues with stability, interfacial recombination, and electron/hole mobility. The following work looks into the fabrication of non-toxic ZnO-based lead-free alternatives to perovskite oxides for use as secondary sensors or electron transport layers along with perovskite halides for application in stacked biomedical wearable devices. Three-phase, lead-free, Zinc Oxide-Graphene-Epoxy electroactive nanocomposite thin films were fabricated. The volume fraction of the Graphene phase was held constant at 10%, while the volume fraction of the ZnO phase was varied from 10–70%. The dielectric constant, capacitance, impedance, resistance, and conductance of the samples were measured using an impedance analyzer, and the results were compared as a function of volume fraction of ZnO to understand the electron transport performance of these thin films. The impedance and dielectric spectra of the nanocomposites were recorded over a frequency range of 20 Hz to 10 MHz. The microstructural properties and cross-section of the thin films were analyzed using a Scanning Electron Microscope. The high sensitivity and electron transport properties of the composite could be potentially utilized in biomedical devices at low- and high-frequency ranges.
... III-V [2,3,[5][6][7], IV [9], metal oxides [10], etc) and complex architectures such as NWs based on core-shell [1,4] or quantum wells [11,12], has been successfully demonstrated mainly through bottom-up based growth mechanisms. Resulting NWs present unique properties such as high NW length-to-diameter ratios-namely aspect ratios-above 100, high surface-to-volume ratios, high crystal quality, and nanometric foot-prints (diameters<100 nm), allowing them to show quantum effects [12][13][14], surface optical phonons [15], ultra-high photo-gains [16,17], as well as, higher signalto-noise ratios [18], higher sensing surface [18,19], higher integrability [20][21][22][23][24], higher mechanical properties [24] and Nanotechnology Nanotechnology 31 (2020) 225604 (13pp) https://doi.org/10.1088/1361-6528/ab76ee ...
... However, the compatibility of NWs with conventional nanofabrication tools is still a critical bottleneck, hindering the efficient integration of NWs in aforementioned applications, and therefore the effective deployment and commercialization of NW based technology in the market. The manipulation and transferring of NWs from the growth substrate to a foreign receiver substrate to realize those applications, is still a challenge that needs further investigations [20][21][22][23][24]. ...
... Assembly techniques based on mechanical forces (contact-printing, stamp-printing and roll-printing) or fluidics (Langmuir-Blodgett and bubble-blown) have demonstrated their validity to produce a large-area, compact, and uniform electronic layers based on multiple semiconducting NWs [20,[22][23][24]28]. Although some of these techniques have demonstrated certain control over the density of assembled NWs and potential to fabricate 3D stacked structures, [21,22,24], they lack control over single NWs, which is interesting for the investigation of their fundamental properties and mechanisms. Moreover, single NW based devices could be particularly interesting for the design of high-performance applications such as single photon detectors or single molecule chemical sensors [29]. ...
Mechanical manipulation of nanowires (NWs) for their integration in electronics is still problematic because of their reduced dimensions, risking to produce mechanical damage to the NW structure and electronic properties during the assembly process. In this regard, contactless NW manipulation based methods using non-uniform electric fields, like dielectrophoresis (DEP) are usually much softer than mechanical methods, offering a less destructive alternative for integrating nanostructures in electronic devices. Here, we report a feasible and reproducible dielectrophoretic method to assemble single GaAs NWs (with radius 35–50 nm, and lengths 3–5 μm) on conductive electrodes layout with assembly yields above 90% per site, and alignment yields of 95%. The electrical characteristics of the dielectrophoretic contact formed between a GaAs NW and conductive electrodes have been measured, observing Schottky barrier like contacts. Our results also show the fast fabrication of diodes with rectifying characteristics due to the formation of a low-resistance contact between the Ga catalytic droplet at the tip of the NW when using Al doped ZnO as electrode. The current-voltage characteristics of a single Ga-terminated GaAs NW measured in dark and under illumination exhibit a strong sensitivity to visible light under forward bias conditions (around two orders of magnitude), mainly produced by a change on the series resistance of the device.
... In these technologies, the detectors should be imperceptible to the human eye and allow creation of transparent optical interfaces, e.g. between a viewer and the outside world 1 . On the other hand, the detectors should also be able to extract multi-dimensional information carried by light, including intensity, direction, wavelength, polarization state, and phase [2][3][4][5][6][7][8][9] . Specifically, spectro-polarimetric detectors are designed to collect valuable spectral and polarization information from a scene. ...
... In that case many more sensors and filters would be required to obtain the same information. Increasingly, nanophotonic elements are used as photodetectors [3][4][5][6][7][8][9] or integrated with image sensors [16][17][18][19][20][21][22][23] to tailor their spectral response. Given the current desire to place detectors on transparent optical elements without being seen, we have the additional challenge that they should not reflect light or perceivably distort optical wavefronts. ...
Compact and lightweight photodetection elements play a critical role in the newly emerging augmented reality, wearable and sensing technologies. In these technologies, devices are preferred to be transparent to form an optical interface between a viewer and the outside world. For this reason, it is of great value to create detection platforms that are imperceptible to the human eye directly onto transparent substrates. Semiconductor nanowires (NWs) make ideal photodetectors as their optical resonances enable parsing of the multi-dimensional information carried by light. Unfortunately, these optical resonances also give rise to strong, undesired light scattering. In this work, we illustrate how a new optical resonance arising from the radiative coupling between arrayed silicon NWs can be harnessed to remove reflections from dielectric interfaces while affording spectro-polarimetric detection. The demonstrated transparent photodetector concept opens up promising platforms for transparent substrates as the base for opto-electronic devices and in situ optical measurement systems.
