Photoswitches and Memories Assembled by Electrospinning Aluminum‐Doped Zinc Oxide Single Nanowires

Abstract

Nanowires and nanotubes are important building blocks for nanoscale optoelectronics, as they can function as miniaturized devices as well as electrical interconnects.[1] Nanodevices such as field-effect transistors (FETs), [2] Schottky diodes, [3] electrical switches, [4] and memories [5] have thus far been demonstrated. As a very promising way for achieving 1D nanostructures, electrospinning has the advantages of device size reduction and more compact component density in circuits. [6,7] Electrospun nanowires exhibit several amazing characteristics, such as very large surface area to volume ratios, [8] flexibility in surface functionalities, [9] and superior mechanical performances.[10] It would be meaningful to combine the electrospinning technique with controllable ceramic nanowires assembly for device fabrication, as this would provide a simple, rapid, and cheap way to construct patterned nanoarrays and circuits. ZnO, with a large direct bandgap of 3.37 eV, is one of the most promising materials for applications such as gas sensors, [11] diodes, [12] solar cells, [13] resonators, [14] and other photoelectric devices. Meanwhile, it is highly desired to prepare 1D ZnO nanostructures doped with a selection of elements for enhancing and controlling their mechanical, electrical, and optical performance. So far, several doped 1D ZnO nanostructures have been synthesized [15][16][17][18][19][20] that are important for practical applications. Aluminum-doped zinc oxide (AZO), as a possible alternative transparent conductive oxide (TCO) to indium tin oxide (ITO), has attracted much attention because of its unique optical and electrical characteristics as well as its low cost and non-toxicity. However, there are few reports on the preparation of AZO nanostructures and their properties, although much work has been carried out on AZO films. In this communication, we report on a photoconductor device that is sensitive to illumination with below-gap light and a memory assembled by electrospinning a single AZO nanowire, both of which, to the best of our knowledge, have never been reported before. For this purpose, well-aligned and highly ordered architectures of 1D nanostructures were required. Although a number of approaches have been demonstrated to collect spatially oriented electrospun nanowires, few attempts have been made to directly obtain oriented electrospun nanowires for device fabrications. [21][22][23] Herein, by using a "Cu bridge" as the cathode, which consists of two conductive copper filaments separated by a void gap of 1 cm width (Fig. 1a), the electrospun nanowires could be uniaxially aligned over long length scales during the e-spinning process (Fig. 1b). The nanowires were then directly transferred to a silicon substrate with a 500 nm-thick thermally grown SiO 2 layer, and calcined at 550°C at a heating rate of 10°C min -1 in air for 3 h to obtain well-aligned polycrystalline AZO nanowires (Fig. 1c). Gold electrodes were then deposited on the AZO nanowires by thermal evaporation using a mask to form channe...

Electrospinning of Nanomaterials and Applications in Electronic Components and Devices

“…64 Aluminum-doped ZnO (AZO) is a low cost and nontoxic transparent and conductive alternative to indium tin oxide (ITO). 65 Single electrospun nanowires of AZO show a highly sensitive photoresponse under below-gap light illumination compared to AZO films. Well-oriented quasi-one-dimensional CuO nanofibers are intrinsic p-type semiconductors, and when assembled in field-effect transistors (FET), serve as a potentional building blocks for low cost logic and switching circuits.…”

One-dimensional ZnO nanostructures: Solution growth and functional properties

“…It has been demonstrated to have enormous applications in electronic, optoelectronic, electrochemical, and electromechanical devices [3][4][5][6][7][8], such as ultraviolet (UV) lasers [9,10], light-emitting diodes [11], field emission devices [12][13][14], high performance nanosensors [15][16][17], solar cells [18][19][20][21], piezoelectric nanogenerators [22][23][24], and nanopiezotronics [25][26][27]. One-dimensional (1D) ZnO nanostructures have been synthesized by a wide range of techniques, such as wet chemical methods [28][29][30], physical vapor deposition [31][32][33], metal-organic chemical vapor deposition (MOCVD) [34][35][36], molecular beam epitaxy (MBE) [37], pulsed laser deposition [38,39], sputtering [40], flux methods [41], eletrospinning [42][43][44], and even top-down approaches by etching [45]. Among those techniques, physical vapor deposition and flux methods usually require high temperature, and easily incorporate catalysts or impurities into the...…”

Electrospinning of ceramic nanofibers: Fabrication, assembly and applications

“…1D ceramic nanomaterials with their large surface-to-volume ratio have the potential for use in various applications where high porosity is desirable [11][12][13]. For example, inorganic nanowires are expected to play an important role as promising building blocks for nanoscale electronic [9,10,15], optoelectronic [15,16] and sensor device [12,17,18]. Most recently, ceramic nanowires have been explored as effective electrode materials for electrochemical energy storage devices [19,20].…”

“…Recent efforts by several research groups have made it possible to generate ceramic nano bers using electrospinning technique [24,[28][29][30][32][33][34][35]. This review will present a brief overview of recent progress in this research area, with a focus on the work carried out in our group [16,. After briefly introducing the basic principles of electrospinning, this paper will review the general experimental procedures for the preparation of electrospinning ceramic nano bers, and will highlight several unique features associated with the technique and illustrate the potential of electrospinning in future research related to ceramic processing.…”