As an extension of our previous proving that ion beam synthesis is an efficient route to form doped silicon nanocrystals (nc’s) [1, 2], we show here that ion beam synthesis, by co-implantion of the dopant and of the constituents of the alloy, followed by a single high temperature anneal, is also a convenient way to grow more complex structures, such as As doped nc’s of Si1-xGex alloys.

Rutherford backscattering spectrometry (RBS) is used to measure the impurity profiles and evaluate the average concentration of the various species (Si, Ge, As). The formation of the nc’s is evidenced by TEM observation and further confirmed by Raman and XRD analysis, which also allow us to estimate the Ge content of the nc’s.

The incorporation of As inside the Si1-xGex nc’s is attested by the presence of the characteristic Ge-As related line in the Raman spectra of the As-doped samples, and strengthened by the increased conductivity of MOS structure including such doped nc’s inside the dielectric film.

This work deals with SU-8 waveguides and waveguide structures fabricated on an oxidized silicon substrate using ‘Focused ion beam (FIB) lithography’. From our experimentation it seems that FIB method is practically not suitable for fabricating long SU-8 waveguide structures, rather it is more suitable for nanoscale modification of already fabricated waveguides, such as, to fabricate photonic crystal structures.

Cold atmospheric pressure plasma has been intensively studied due to growing interest in biomedical applications. For example, it has been revealed that the plasma-irradiated cell culture medium (PAM: Plasma Activated Medium) shows antitumor effect as well as the direct plasma treatment. Long-lived reactive oxygen and nitrogen species (RONS), such as hydrogen peroxide (H2O2), nitrite (NO2 -), and nitrate (NO3 -), are considered as a main product in PAM. Therefore, investigation of the production characteristics of RONS in PAM with different experimental parameters is important. Here, we focused on humidification of feed gas (argon or helium) and effect of gap between the nozzle of the plasma jet and liquid surface. As a result, H2O2 concentration was increased by humidification of both feed gases. However, the concentration of NO2 - and NO3 - was decreased by the humidification of helium. In addition, the remarkable effect of the humidification on H2O2 production was observed when the plasma jet was in contact with the liquid surface.

We have produced plasma activated water (PAW) using air, O2, N2, He and Ar atmospheric pressure dielectric barrier discharge plasma irradiation to deionized water. Then, PAW was kept for 1 hour or 1 day at room temperature to reduce concentrations of short lifetime reactive oxygen species and reactive nitrogen species before supplying to plants. O2, air and N2 PAW induces growth enhancement of plants. For 1 hour PAW supply the longest seedling length after 3 days cultivation is 1.62, 1.38, 1.13, 1.12, and 1.04 times long for air, O2, He, N2, and Ar plasmas compared with the length for thecontrol, whereas for 1 day PAW supply it is 1.52, 1.28, 1.13, 1.10, and 1.08 times long for air, O2, He, N2 and Ar. Therefore, long lifetime reactive oxygen nitrogen species in PAW is effective for the growth enhancement.

Colloidal Au and Pd nanoparticles (NPs) were directly electrochemically synthesized, by sacrificial anode electrolysis (SAE), on hydrothermal ZnO nanostructures, previously desiccated; further, the functionalized ZnO nanostructures were subjected to thermal annealing at 550°C to obtain stable ZnO nanorods (NRs), superficially decorated by naked metal NPs. The both pristine and metal functionalized ZnO NRs were proposed as active layer in chemiresistive sensors for environmental monitoring to detect pollutant gases (e.g. NO2, C4H10).

The effect of the presence and of the chemical nature of the deposited metal NPs on the performance of ZnO NRs-based gas sensor (e.g. sensitivity, selectivity and recovery) was evaluated, comparing the sensing results with those of pristine ZnO NRs. In particular, the gas sensing properties of pristine and metal-functionalized ZnO NRs were studied at an operating temperature of 300°C towards a various range of concentration of different gaseous pollutants.

An electrophoretic process is proposed to deposit electrochemically-preformed Au or Pd NPs, with controlled size, directly on MWCNTs-based chemiresistors to improve the detection of aromatic pollutants, compared to pristine ones.

The sensing properties of pristine and functionalized MWCNTs were evaluated at an operating temperature of 40°C towards various concentrations of one aromatic pollutant, belonging to the dangerous BTEX class of compounds, m-Xylene. The sensing performance was related to the metal used in the functionalization process. Metal-doped MWCNTs sensors exhibited a very high gas sensitivity to m-Xylene even at low (80 ppb) concentration at low operating temperature (40°C), good reversibility and repeatability, with the sensing properties controlled by the type of deposited metal catalyst.

The results indicate that Metal-modified MWCNT-based chemiresistive gas sensors has good potential in practical applications, due to its remarkable performance, low power consumption, and facile synthesized methods.

Active inkjet materials are invoked in the fabrication of optoelectronic devices. These types of multilayer assemblies contain a variety of commercially available ink formulations. It is envisioned that a dielectric SU-8 material can be used in a FET-like structure to form an interlayer between conductive silver and semi-conductive MWCNT-doped PEDOT:PSS ink layers. These printed structures may be fabricated onto a polyimide based flexible substrate, for instance. These structures are a starting point for offering valuable information on layer-on-layer printing interactions and interface problematics within a complete inkjet device fabrication.

Flexible electronics manufacturing from functional inks is a versatile approach gaining interest from both industry and academia at an accelerated pace; towards its full development, research studies establishing connections between the inks processing conditions and final materials functionalities become necessary. In this work, we report on the relations between synthesis, continuous - flow direct writing parameters, and low energy intensity post-processing of functional TiO2 hybrid ink patterns. Such inks are printed on heat sensitive polymer substrates with typical application in dye solar cell photoelectrodes; nevertheless, their versatility spans a wide range of other applications from sensors to photocatalysts. For the ink formulation, we use an initial crystalline nanoparticle TiO2 phase that provides the main functionality of the printed films. We also add a Ti-precursor that, when post-treated, provides connecting paths for the initial phase thus forming continuous porous structures. We find that the ink’s formulation plays a pivotal role by providing the means for tuning its rheological properties (necessary for successful direct writing), the ink-substrate interactions, and the printed microstructures. We further discuss the implications of such compositional variations, introduced when adding polymeric agents, such as polyacrylic acid, on the crystallization of the Ti-organic precursor into TiO2 bridges between the nanoparticles. We finally report on the electrical properties of the printed TiO2 photoelectrodes as compared to conventionally fabricated counterparts. The design, continuous – flow direct writing, and the subsequent mild thermal-energy treatments of hybrid sol-gel based TiO2 inks may hold the key for large-scale and sustainable additive manufacturing of flexible functional components for a range of applications.

Stainless steel substrates enable a combination of low cost, flexibility, durability, high processing temperatures, and sub-100 um thickness making it well suited for sheet based and roll-to-roll processing. NFC (13.56 MHz) based circuits using high performance polysilicon TFTs on steel sheets have been manufactured using a hybrid printed process in a production environment. The process scheme utilizes a hybrid, additive materials approach encompassing low cost manufacturing steps such as slot die coating and screen printing of silicon and dopant inks to enable a high throughput, low cost, manufacturing flow. This paper describes the approach for migrating from a sheet-based hybrid process flow to a R2R-based process. A comparison of substrate choices and considerations for R2R process integration is presented. A sensitive electrical method for evaluating the feasibility of R2R-based process integration schemes and materials selection is presented. MIM capacitor leakage, TFT device characteristics, NFC circuit performance, and defect density considerations are shown as a function of steel substrate bending, down to a diameter of 0.75 inches. Electrical characteristics and optical inspections show no measurable change to insulator characteristics, demonstrating a high degree of flexibility and overall device and process capability for R2R processing.