Red-green-blue light sensitivity of oxide nanowire transistors for transparent display applications

In this study, the sensitivity of oxide nanowire transistors under red (R, 470 nm), green (G, 530 nm), and blue (B, 625 nm) light illumination was investigated. As the wavelength of light illuminating the nanowire channel region became shorter, a negative shift of threshold voltage, degradation of subthreshold slope, and increase of on-current were observed. This phenomenon can be explained in terms of photoinduced holes, creating interfacial traps between the gate dielectric and nanowire channel or reacting with oxygen ions on the surface of the nanowires. Thus, the attempt to minimize characteristic changes due to all RGB light sources was performed by employing ultraviolet-ozone treatment and passivation process. As a result, we could successfully fabricate oxide nanowire transistors providing high optical reliability which has broadened the possibilities for applying it to transparent and/or flexible pixel operation circuitry for displays with high optical reliability. Copyright 2013 Author(s). This article is distributed under a Creative Commons Attribution 3.0 Unported License. [http://dx.doi.org/10.1063/1.4789405

Effect of Gamma-Ray Irradiation on the Growth of Au Nano-Particles Embedded in the Germano-Silicate Glass Cladding of the Silica Glass Fiber and its Surface Plasmon Resonance Response

The effect of γ-ray irradiation on the surface plasmon resonance (SPR) sensing capability of refractive index (n = 1.418–1.448) of the silica glass optical fiber comprised of germano-silicate glass cladding embedded with Au nano-particles (NPs) was investigated. As the γ-ray irradiation increased from 1 h to 3 h with the dose rate of 1190 Gy/h, the morphology of the Au NPs and the SPR spectrum were found to change. The average diameter of Au NPs increased with the aspect ratio from 1 to 2, and the nano-particles became grown to the clusters. The SPR band wavelength shifted towards a longer wavelength with the increase of total dose of γ-ray irradiation regardless of the corresponding refractive indices. The SPR sensitivities (wavelength/refractive index unit, nm/RIU) also increased from 407 nm/RIU to 3553 nm/RIU, 1483 nm/RIU, and 2335 nm/RIU after the γ-ray irradiation at a total dose of 1190 Gy, 2380 Gy, and 3570 Gy, respectively

Nanoscale contacts between semiconducting nanowires and metallic graphenes

Metal–semiconductor (M–S) junctions are important components in many semiconductor devices, and there is growing interest in realizing high quality M–S contacts that are optically transparent. In this paper, we present our investigations into the characteristics of M–S junction in a semiconducting ZnO nanowire that was directly grown on a multilayer graphene film (MGF). The synthesized nanowires were fabricated into two-terminal devices with MGF as one contact and Al as the other contact. By comparison with devices employing Al contacts at both ends, the nanowire resistivity and specific contact resistivity of the MGF–nanowire contact can be extracted. The extracted specific contact resistivity of the MGF–ZnO nanowire contact (1.5 × 10-5 Ω-cm2) is comparable to reported Al–ZnO contacts. Based on the assumption that thermionic-field emission is the dominant mechanism, we obtained the zero bias effective barrier height of 0.413 eV for the MGF–ZnO nanowire Schottky contact. We have thus demonstrated that as a result of the enhanced tunneling at the contact, the MGF–nanowire contact exhibits near-ohmic current-voltage characteristics with a low contact resistance which suggests MGF as a promising candidate for future transparent displays using ZnO nanowire transistors

Interface studies of N-2 plasma-treated ZnSnO nanowire transistors using low-frequency noise measurements

Due to the large surface-to-volume ratio of nanowires, the quality of nanowire-insulator interfaces as well as the nanowire surface characteristics significantly influence the electrical characteristics of nanowire transistors (NWTs). To improve the electrical characteristics by doping or post-processing, it is important to evaluate the interface characteristics and stability of NWTs. In this study, we have synthesized ZnSnO (ZTO) nanowires using the chemical vapor deposition method, characterized the composition of ZTO nanowires using x-ray photoelectron spectroscopy, and fabricated ZTO NWTs. We have characterized the current-voltage characteristics and low-frequency noise of ZTO NWTs in order to investigate the effects of interface states on subthreshold slope (SS) and the noise before and after N-2 plasma treatments. The as-fabricated device exhibited a SS of 0.29 V/dec and Hooge parameter of similar to 1.20 x 10(-2). Upon N-2 plasma treatment with N-2 gas flow rate of 40 sccm (20 sccm), the SS improved to 0.12 V/dec (0.21 V/dec) and the Hooge parameter decreased to similar to 4.99 x 10(-3) (8.14 x 10(-3)). The interface trap densities inferred from both SS and low-frequency noise decrease upon plasma treatment, with the highest flow rate yielding the smallest trap density. These results demonstrate that the N-2 plasma treatment decreases the interface trap states and defects on ZTO nanowires, thereby enabling the fabrication of high-quality nanowire interfaces

Laser Drilling Process for 3-D Stacked Flexible Integrated Circuit

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Fabrication of Highly Transparent Nanowire Transistors with One-Step-Processed Graphene Gate-Source-Drain Electrodes

We report the fabrication of a highly transparent nanowire transistor using graphene as the gate and source-drain electrodes. Graphene gate-source-drain electrodes were simultaneously formed by a single-step transfer process. The graphene electrode and the nanowire channel exhibited near-ohmic contact characteristics. The threshold voltage, subthreshold slope, and mobility of the fabricated top-gate-structural In2O3 nanowire transistor with graphene gate-source-drain electrodes were -4.54 V, 0.43 V/dec, and 78 cm(2)/(V.s) respectively. The optical transmissions in the region that contained nanowire transistors on the quartz substrate were 88.5-90.3% in the 400-780nm wavelength range. (C) 2013 The Japan Society of Applied Physic

Luminescence and decay characteristics of Tb3+-doped fluorophosphate glasses

Tb3+-doped fluorophosphate glasses with the composition of P2O5–K2O–SrF2–Al2O3–x Tb4O7 (where x = 0.1, 0.5, 1.0, 2.0 and 4.0 mol%) were prepared by a conventional high temperature melt quenching technique and characterized through absorption, emission, excitation and decay measurements. From the emission studies, a strong green emission at around 546 was observed, which corresponds to the 5D4 → 7F5 transition of Tb3+ ion. Green/blue intensity ratios (IG/IB) were evaluated as a function of Tb3+ concentration and vice versa. Higher IG/IB intensity ratio confirms the higher covalency between Tb–O bond and higher asymmetry around the Tb3+ ions in the present fluorophosphate glasses. The decay curves for the 5D4 level of Tb3+ ion were measured and found that they exhibited single exponential nature irrespective to the dopant concentration. The experimental lifetime was determined using single exponential fitting and found that it increased from 2.65 to 2.95 ms when Tb3+ concentration increased from 0.1 mol% to 4.0 mol%. The derived properties were compared to the other Tb3+-doped glasses in order to see the potentiality of the material for visible laser gain media at 546 nm

Oxygen plasma exposure effects on indium oxide nanowire transistors

In2O3 nanowire transistors are fabricated with and without oxygen plasma exposure of various regions of the nanowire. In two-terminal devices, exposure of the channel region results in an increased conductance of the channel region. For In2O3 nanowire transistors in which the source/drain regions are exposed to oxygen plasma, the mobility, on–off current ratio and subthreshold slope, are improved with respect to those of non-exposed devices. Simulations using a two-dimensional device simulator (MEDICI) show that improved device performance can be quantified in terms of changes in interfacial trap, shifts in fixed charge densities and the corresponding reduction in Schottky barrier height at the contacts

Classification of Fresh and Frozen-Thawed Beef Using a Hyperspectral Imaging Sensor and Machine Learning

The demand for safe and edible meat has led to the advancement of freeze-storage techniques, but falsely labeled thawed meat remains an issue. Many methods have been proposed for this purpose, but they all destroy the sample and can only be performed in the laboratory by skilled personnel. In this study, hyperspectral image data were used to construct a machine learning (ML) model to discriminate between freshly refrigerated, long-term refrigerated, and thawed beef meat samples. With four pre-processing methods, a total of five datasets were prepared to construct an ML model. The PLS-DA and SVM techniques were used to construct the models, and the performance was highest for the SVM model applying scatter correction and the RBF kernel function. These results suggest that it is possible to construct a prediction model to distinguish between fresh and non-fresh meat using the spectra obtained by purifying hyperspectral image data cubes, which can be a rapid and non-invasive method for routine analyses of the meat storage state