Highly transparent and reproducible nanocrystalline ZnO and AZO thin films grown by room temperature pulsed-laser deposition on flexible Zeonor plastic substrates

Inguva, Saikumar; Vijayaraghavan, Rajani K.; McGlynn, Enda; Mosnier, Jean-Paul

doi:10.1088/2053-1591/2/9/096401

Cited by 19 publications

(12 citation statements)

References 63 publications

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“…These values correspond to the (002) reflection of the wurtzite structure (ICSD# 082029), showing a preferred orientation with the c-axis perpendicular to the ZnO and AZO films surface. The peak position was similar to that reported previously for ZnO thin films produced by plasma deposition methods [31].The crystallite sizes of the deposited films were measured using Scherrer equation and the results were 38 and 23 nm for ZnO and AZO, respectively [32]. Software analyses (Xpert high score) of the diffraction peak profiles also indicated higher lattice strain for AZO than for ZnO thin film, likely due to Al incorporation in the ZnO lattice.…”

Section: Resultssupporting

confidence: 81%

Mediator-free interaction of glucose oxidase, as model enzyme for immobilization, with Al-doped and undoped ZnO thin films laser-deposited on polycarbonate supports

V.T.K.P.

Inguva

Krishnamurthy

et al. 2017

Enzyme and Microbial Technology

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Research Highlights: Electrochemical interaction of ZnO and AZO thin films with the enzyme glucose oxidase was studied.  Nature of interaction of GOx with AZO was explored using XPS.  Mechanism of the electron transfer between GOx and AZO/ZnO was studied using EIS.  The results show that AZO is preferable to ZnO for GOx immobilization and glucose sensor development. Abstract:Al doped and undoped ZnO thin films were deposited by pulsed-laser deposition on polycarbonate sheets. The films were characterized by optical transmission, Hall effect measurement, XRD and SEM. Optical transmission and surface reflectometry studies showed good transparency with thicknesses ~100 nm and surface roughness of 10 nm. Hall effect measurements showed that the sheet carrier concentration was -1.44 x 10 15 cm -2 for AZO and -6 x 10 14 cm -2 for ZnO. The films were then modified by drop-casting glucose oxidase (GOx) without the use of any mediators. Higher protein concentration was observed on ZnO as compared to AZO with higher specific activity for ZnO (0.042 U mg -1 ) compared to AZO (0.032 U mg -1 ), and was in agreement with cyclic voltemmetry (CV). X-ray photoelectron spectroscopy (XPS) suggested that the protein was bound by dipole interactions between AZO lattice oxygen and the amino group of the enzyme. Chronoamperometry showed sensitivity of 5.5 µA mM -1 cm -2 towards glucose for GOx/AZO and 2.2 µA mM -1 cm -2 for GOx/ZnO. The limit of detection (LoD) was 167 µM of glucose for GOx/AZO, as compared to 360 µM for GOx/ZnO. The linearity was 0.28-28 mM for GOx/AZO whereas it was 0.6-28 mM for GOx/ZnO with a response time of 10s. Possibly due to higher enzyme loading, the decrease of impedance in presence of glucose was larger for GOx/ZnO as compared to GOx/AZO in electrochemical impedance spectroscopy (EIS). Analyses with clinical blood serum samples showed that the systems had good reproducibility and accuracy. The characteristics of novel ZnO and AZO thin films with GOx as a model enzyme, should prove useful for the future fabrication of inexpensive, highly sensitive, disposable electrochemical biosensors for high throughput diagnostics.

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Section: Resultssupporting

confidence: 81%

Mediator-free interaction of glucose oxidase, as model enzyme for immobilization, with Al-doped and undoped ZnO thin films laser-deposited on polycarbonate supports

V.T.K.P.

Inguva

Krishnamurthy

et al. 2017

Enzyme and Microbial Technology

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“…In addition, the electron diffraction patterns of AZO/Al 2 O 3 multilayers manifested the structure of crystalline/amorphous. Both AZO layers grown on the anodized AlO x :Nd gate insulator and PLD prepared Al 2 O 3 layer showed the similar diffraction plane of (002) (common in as-deposited PLD grown AZO or ZnO as reported [ 20 , 21 ]), suggesting that the AZO/Al 2 O 3 heterojunction unit can be well repeated by PLD method without the effect of different underlayers. Moreover, there were no obvious structural differences between the anodized AlO x :Nd gate insulator and PLD grown Al 2 O 3 layers.…”

Section: Resultssupporting

confidence: 69%

All-Aluminum Thin Film Transistor Fabrication at Room Temperature

et al. 2017

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Bottom-gate all-aluminum thin film transistors with multi conductor/insulator nanometer heterojunction were investigated in this article. Alumina (Al2O3) insulating layer was deposited on the surface of aluminum doping zinc oxide (AZO) conductive layer, as one AZO/Al2O3 heterojunction unit. The measurements of transmittance electronic microscopy (TEM) and X-ray reflectivity (XRR) revealed the smooth interfaces between ~2.2-nm-thick Al2O3 layers and ~2.7-nm-thick AZO layers. The devices were entirely composited by aluminiferous materials, that is, their gate and source/drain electrodes were respectively fabricated by aluminum neodymium alloy (Al:Nd) and pure Al, with Al2O3/AZO multilayered channel and AlOx:Nd gate dielectric layer. As a result, the all-aluminum TFT with two Al2O3/AZO heterojunction units exhibited a mobility of 2.47 cm2/V·s and an Ion/Ioff ratio of 106. All processes were carried out at room temperature, which created new possibilities for green displays industry by allowing for the devices fabricated on plastic-like substrates or papers, mainly using no toxic/rare materials.

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“…COPs are also recognized for their low water absorption and high mechanical and dimensional stability when in contact with liquids, and as such make extremely suitable platforms for microfluidic devices when compared with previously used alternatives. Owing to these exceptional properties, COP-based devices have been utilised for various applications such as substrates for chromatographic stationary phases [2] and microfluidic devices for the analysis of drugs [3], IR waveguide coatings [4] and as substrates for laser deposited nanomaterials [5].…”

Section: Introductionmentioning

confidence: 99%

Microchannel fabrication on cyclic olefin polymer substrates via 1064 nm Nd:YAG laser ablation

McCann

Bagga

Groarke

2016

Applied Surface Science

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This paper presents a method for fabrication of microchannels on cyclic olefin polymer films that have application in the field of microfluidics and chemical sensing. Continuous microchannels were fabricated on 188-µm-thick cyclic olefin polymer substrates using a picosecond pulsed 1064 nm Nd:YAG laser. The effect of laser fluence on the microchannel morphology and dimensions was analysed via scanning electron microscopy and optical profilometry. Single laser passes were found to produce v-shaped microchannels with depths ranging from 12 to 48 µm and widths from 44 to 154 2 µm. The ablation rate during processing was lower than predicted theoretically. Multiple laser passes were applied to examine the ability for finer control over microchannel morphology with channel depths ranging from 22 µm to 77 µm and channel widths from 59 µm to 155 µm. For up to five repeat passes, acceptable reproducibility was found in the produced microchannel morphology. Infrared spectroscopy revealed that the polymer surface chemistry was not significantly altered via the laser ablation process. These results were compared to other work conducted on cyclic olefin polymers.

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Highly transparent and reproducible nanocrystalline ZnO and AZO thin films grown by room temperature pulsed-laser deposition on flexible Zeonor plastic substrates

Cited by 19 publications

References 63 publications

Mediator-free interaction of glucose oxidase, as model enzyme for immobilization, with Al-doped and undoped ZnO thin films laser-deposited on polycarbonate supports

Mediator-free interaction of glucose oxidase, as model enzyme for immobilization, with Al-doped and undoped ZnO thin films laser-deposited on polycarbonate supports

All-Aluminum Thin Film Transistor Fabrication at Room Temperature

Microchannel fabrication on cyclic olefin polymer substrates via 1064 nm Nd:YAG laser ablation

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