ARTICLES NATURE MATERIALS DOl: 10.1038/NMAT3404 黝懿圃 N团 d下 Conductance (us) °。4。86 1234567891011121314 Number of turns Device index Figure 2 Macroporous and flexible nanowire nanoES. a, Device fabrication schematics. (D)Reticular nanowire FET devices. (ID) Mesh nanowire FET evices Light blue: silicon oxide substrates: blue: nickel sacrificial layers; green: nanoES; yellow dots: individual nanowire FETs. b, 3D reconstructed onfocal fluorescence micrographs of reticular nanoES viewed along the y(i)and x(ID)axes. The scaffold was labelled with rhodamine 6G. The overall size of the structure, x-y-z=300-400-200um. Solid and dashed open magenta squares indicate two nanowire FeT devices located on different planes along the x axis Scale bars, 20 um. c, SEM image of a single-kinked-nanowire FET within a reticular scaffold, showing (1)the kinked nanowire, (2)metallic interconnects(dashed magenta lines)and (3)the Su-8 backbone Scale bar, 2 um. d, Photograph of a mesh device, showing(1)nanowires, (2)metal lterconnects and ( 3)Su-8 structural elements. The circle indicates the position of a single- nanowire FET Scale bar, 2 mm. e, Photograph of a partially rolled-up mesh device Scale bar, 5mm. f, SEM image of a loosely packed mesh nanoES, showing the macroporous structure Scale bar, 100 um g, Histograms of nanowire FET conductance and sensitivity in one typical mesh nanoES. The conductance and sensitivity were measured in the water-gate configuration without rolling. The device yield for this mesh nanoES is 95% h, Water-gate sensitivity and conductance of a nanowire FET in a mesh device during the rolling Upper panel, schematic of the nanowire fet position(yellow dot) during the rolling process; 0-6 denote the number of turns. i, Relative change in conductance and sensitivity of 14 nanow s evenly distributed throughout a fully rolled-up mesh device. Upper panel, schematic 7uSv-(Fig. 2g). Representative conductance(G)data( Fig. 2h) and showed that the properties were approximately independent of from a single-nanowire FET( Fig. 2h, yellow dots, upper panel) location. Furthermore, 14 devices evenly distributed on six layers during the rolling process showed a <0 17 uS conductance change of a rolled-up scaffold( Fig. 2i) showed maximum AG=6.8% AG)or <2.3% total change for 6 revolutions. Device sensitivity and AS=6.9% versus the unrolled state, demonstrating device (S)remained stable with a maximum change(AS)of 0.031usv-, robustness. Repetitive rolling and relaxation to the flat state or 1.5% variation. The stable performance during rolling can be did not degrade the nanowire FET performance. These findings explained by the low estimated strains of metal (<0.005%)and SU-8 suggest the potential for reliable sensing/recording of dynamic and (<0. 27%)in this tubular construct(Supplementary Information), deformable systems NATURE MATERIALS I VOL 11 I NOVEMBER 2012 I G 2012 Macmillan Publishers Limited All rights reservedARTICLES NATURE MATERIALS DOI:10.1038/NMAT3404 x z y y z x de f 1 2 3 4 6 5 7 8 9 10 11 12 13 14 ~1.7 mm 1.5 mm 1 2 3 0 2 1 3 15 10 5 0 Count 10 5 0 Count Conductance (μS) gh i 0 2 4 6 8 4 6 8 10 12 b c I II 1 3 2 Sensitivity (μS V¬1) 9 8 7 2.3 2.1 1.9 0 1 2 3 4 5 6 Sensitivity (μS V¬1) Number of turns Conductance (μS) 10 5 0 ¬5 1 2 3 4 5 6 7 8 9 10 11 12 13 14 Device index ΔG/G, ΔS/S (%) a I II 4 5 6 Figure 2 | Macroporous and flexible nanowire nanoES. a, Device fabrication schematics. (I) Reticular nanowire FET devices. (II) Mesh nanowire FET devices. Light blue: silicon oxide substrates; blue: nickel sacrificial layers; green: nanoES; yellow dots: individual nanowire FETs. b, 3D reconstructed confocal fluorescence micrographs of reticular nanoES viewed along the y (I) and x (II) axes. The scaffold was labelled with rhodamine 6G. The overall size of the structure, x–y–z = 300–400–200 µm. Solid and dashed open magenta squares indicate two nanowire FET devices located on different planes along the x axis. Scale bars, 20 µm. c, SEM image of a single-kinked-nanowire FET within a reticular scaffold, showing (1) the kinked nanowire, (2) metallic interconnects (dashed magenta lines) and (3) the SU-8 backbone. Scale bar, 2 µm. d, Photograph of a mesh device, showing (1) nanowires, (2) metal interconnects and (3) SU-8 structural elements. The circle indicates the position of a single-nanowire FET. Scale bar, 2 mm. e, Photograph of a partially rolled-up mesh device. Scale bar, 5 mm. f, SEM image of a loosely packed mesh nanoES, showing the macroporous structure. Scale bar, 100 µm. g, Histograms of nanowire FET conductance and sensitivity in one typical mesh nanoES. The conductance and sensitivity were measured in the water-gate configuration without rolling. The device yield for this mesh nanoES is 95%. h, Water-gate sensitivity and conductance of a nanowire FET in a mesh device during the rolling process. Upper panel, schematic of the nanowire FET position (yellow dot) during the rolling process; 0–6 denote the number of turns. i, Relative change in conductance and sensitivity of 14 nanowire FETs evenly distributed throughout a fully rolled-up mesh device. Upper panel, schematic of the nanowire FET position (yellow dots). In h,i the thicknesses of the tubular structures have been exaggerated for schematic clarity. ∼7 µS V−1 (Fig. 2g). Representative conductance (G) data (Fig. 2h) from a single-nanowire FET (Fig. 2h, yellow dots, upper panel) during the rolling process showed a <0.17 µS conductance change (1G) or <2.3% total change for 6 revolutions. Device sensitivity (S) remained stable with a maximum change (1S) of 0.031 µS V−1 , or 1.5% variation. The stable performance during rolling can be explained by the low estimated strains of metal (<0.005%) and SU-8 (<0.27%) in this tubular construct (Supplementary Information), and showed that the properties were approximately independent of location. Furthermore, 14 devices evenly distributed on six layers of a rolled-up scaffold (Fig. 2i) showed maximum 1G = 6.8% and 1S = 6.9% versus the unrolled state, demonstrating device robustness. Repetitive rolling and relaxation to the flat state did not degrade the nanowire FET performance. These findings suggest the potential for reliable sensing/recording of dynamic and deformable systems. 988 NATURE MATERIALS | VOL 11 | NOVEMBER 2012 | www.nature.com/naturematerials © 2012 Macmillan Publishers Limited. All rights reserved