Fig. 1. (Color online) (a) Schematic illustrations of the formation mechanism of GaAs NWs. (b) SEM images of high aspect ratio GaAs NW produced from a 600 nm wide square Au mesh pattern in H₂SO₄ and KMnO₄ solution at 40–45 °C. Reprinted from Ref. [9] with permission, Copyright 2011, American Chemical Society.

Fig. 2. (Color online) Illustration depicting the growth mechanism of a MAPbI₃·DMF NW by in situ monitoring with an UV−Vis microspectrometer. Reprinted from Ref. [20] with permission, Copyright 2018, American Chemical Society.

Fig. 3. (Color online) (a) Schematic of the process flow for contact printing of nanowire arrays. (b) Dark-field optical and (c) SEM images of Ge NWs (d ~ 30 nm) printed on a Si/SiO₂ substrate showing highly dense and aligned monolayer of nanowires. The self-limiting process limits the transfer of NWs to a single layer, without significant NW bundling. (d) and (e) Optical images of double layer printing for Si NW (d ~ 30 nm) cross assembly. Reprinted from Ref. [28] with permission, Copyright 2008, American Chemical Society; (f) (Top) SEM and (bottom) schematic of a back-gated InGaAs NW array FET. The scale bar is 1 μm. (g) Transfer characteristic of a representative InGaAs NW parallel device under V_DS = 0.1, 0.4, 0.7, and 1 V, about 200 NWs bridging S/D. (h) Mobility assessment of this NW array device under V_DS = 0.1 V. Reproduced from Ref. [29] with permission, Copyright 2012, American Chemical Society.

Fig. 4. (Color online) Schematic of the spray-coating process that involves a direct transfer of NW suspension to the receiver substrates. (a) Schematic and scanning electron microscopy (SEM) image of the NW sample used in this study. (b) Schematic of the NW suspension. (c) Schematic of the assembled apparatus used in this study. (d) Schematic and optical microscopy image of Si NW spray-coated on the SiO_x/Si substrate. Reprinted from Ref. [31] with permission, Copyright 2012, American Chemical Society.

Fig. 5. (Color online) Schematic of two-step all-printable process and materials characterization. (a) Printing setup schematic. (b, c) Electrospinning ejection from the tailored cone apex. (d, e) Optical images of the as-printed electrospun ZnAc/PVA nanofibres with 5 and 10 mm spacing, respectively. (f) SEM image of an as-calcinated ZnO GNW. (g) Transmission electron microscopy image of a GNW. Reprinted from Ref. [44] with permission, Copyright 2014, Springer Nature.

Fig. 6. (Color online) (a) Schematic representation of the fabrication steps: encapsulation in PDMS and peel-off of the membrane; deposition of the back metal contact; deposition of the top transparent contact composed of a silver nanowire mesh. (b) Bird’s eye view SEM image of the top surface of the detector. (c) Top view SEM image of an individual nitride NW contacted with silver nanowires. (d) Device photo illustrating its flexibility. Reproduced from Ref. [25] with permission, Copyright ©2016, American Chemical Society.

Fig. 7. (Color online) (a) Scheme of the PVA/CNT flexible photodetector. (b) I–V characteristic of the photodetector with and without 523 K blackbody illumination in 25 wt% CNT device. (c) Responsivity and detectivity trends according to the CNT content wt%. Reproduced from Ref. [4] with permission, Copyright 2018, American Chemical Society.

Fig. 8. (Color online) (a) Schematic of the measurement setup of the flexible percolative Si NW photodetector; (b) The transient photocurrent of the photocurrent. (c) The rise time and decay time, (d) the photoresponse at different frequency, (e) time-dependent photocurrent and dark current when the photodetector is bent or flat, and (f) the photocurrent and dark current of the flexible percolative Si NW photodetector as a function of bending cycles. Reproduced from Ref. [67] with permission, Copyright 2018, American Chemical Society.

Fig. 9. (Color online) (a) Schematic and (b) the band diagram of the transfer process of the GaN NW/graphene sandwich photodetector. Reproduced from Ref. [75] with permission, Copyright 2018, American Chemical Society.

Fig. 10. (Color online) (a) I–V characteristic of the ZnO NW array/ PbS QDs photodetector under the illumination of different wavelength. (b) Transient response of the photodetector under different wavelength. Reproduced from Ref. [81] Copyright 2017 The Authors. Published by WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Fig. 11. (Color online) (a) The rise time and decay time and (b) the responsivity and detectivity curves of the perovskite NW photodetector at 0 V. Reprinted from Ref. [112] with permission, Copyright 2019, WILEY-VCH Verlag GmbH & Co.

Fig. 12. (Color online) (a) Human fingertip radiation detection at different by the CNT/PVA image sensor. (b) (left) The thermal image of the human finger on the right. Reprinted from Ref. [4] with permission, Copyright 2018, American Chemical Society.

Fig. 13. (Color online) (a) The schematic of the FTNG integrated UV detector. (b) Photoresponse of the UV detector with different UV intensity. (c) Plot of UV detector voltage against the UV intensity. Reprinted from Ref. [127] with permission, Copyright 2012, American Chemical Society.