(2011), Advanced Materials, 23: 3332–3336. doi: 10.1002/adma.201101358

Melanin Layer on Silicon: an Attractive Structure for a Possible Exploitation in Bio-Polymer Based Metal–Insulator–Silicon Devices

M. Ambrico, P F Ambrico , A. Cardone, T. Ligonzo, S. R. Cicco, R. Mundo, V. Augelli, and G.M. Farinola

Abstract.Synthetic melanin based metal–insulator–semiconductor devices are fabricated for the first time thanks to silicon surface wettability modification by using dielectric barrier discharge plasma. Ambipolar charge trapping in air and ion drift mechanisms under vacuum are identified by capacitance–voltage hysteresis loops. These results aim to foresee the possible integration of synthetic melanin layers as a novel capacitor in organic polymer based devices.

HOT TOPIC in Organic electronics
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IOP J. Phys. D. HighLights 2010 

2010 J. Phys. D: Appl. Phys. 43 325201 doi: 10.1088/0022-3727/43/32/325201

Thermoluminescence study of the trapped charge at an alumina surface electrode in different dielectric barrier discharge regimes

P F Ambrico , M Ambrico , A Colaianni , L Schiavulli , G Dilecce and S De Benedictis

Abstract.In this study, the charge trapping effect in alumina dielectric surfaces has been deeply investigated by means of a dedicated dielectric barrier discharge apparatus in different discharge regimes and gas mixtures. This work further validates our previous findings in the case of air discharges in a filamentary regime. Long lasting charge trapping has been evidenced by ex situ thermoluminescence characterizations of alumina dielectric barrier plates exposed to a plasma. The density of trapped surface charges was found to be higher in the glow discharge with respect to pseudo-glow and filamentary regimes, and for all regimes the minimum trap activation temperature was 390 K and the trap energy was less than or around 1 eV. This implies that in the case of glow discharges a higher reservoir of electrons is present. Also, the effect was found to persist for several days after running the discharge

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Latest Published Articles (year 2011)

Plasma Processes and Polymers, n/a. doi: 10.1002/ppap.201000148

Single-Step Plasma Process Producing Anti-Reflective and Photovoltaic Behavior on Crystalline Silicon

Rosa Di Mundo, Marianna Ambrico, Paolo Francesco Ambrico, Riccardo d'Agostino, Francesca Italiano, Fabio Palumbo
Article first published online: 14 FEB 2011

Nanostructured SiliconAbstract. Reactive ion etching (RIE) plasma processes fed with CF4 have been investigated as single-step maskless method for nanotexturing the surface of crystalline silicon. Variation of surface topography under different plasma conditions has been evaluated with scanning electron microscopy and correlated with total, diffuse, and specular reflectance. Chemical features have been evaluated by X-ray photoelectron spectroscopy and current-voltage characteristics have been measured under dark and illuminated conditions. Results indicate that a widely tunable nanoscale texture can be generated onto silicon surface leading to a reduced total reflectance. A significant uptake of carbon and fluorine is detected onto treated silicon with fluorine mainly in ionic form. Further, the plasma modification is per se capable, without further doping procedures, to generate a photovoltaic behavior onto treated silicon, with higher short circuit current in less reflective samples.

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Plasma Sources Science and Technology - 20 025010 doi: 10.1088/0963-0252/20/2/025010 JUST PUBLISHED

ICCD microscopic imaging of a single micro-discharge in surface coplanar DBD geometry: determination of luminous diameter of N2 and Ar streamers

Milan Simek, Paolo Francesco Ambrico and Vaclav Prukner

ICCD High Spatial and Temporal ResolutionTime-resolved images of a single-surface dielectric barrier micro-discharge were obtained by employing ICCD microscopy with high spatial and time resolution. The micro-discharge was repetitively produced by using amplitude-modulated AC high voltage waveforms applied to the coplanar electrode geometry in a reactor, fed either with high-purity Ar or N2 at atmospheric pressure. Driving high-voltage amplitude was set so as to initiate just one single micro-discharge per one AC half-cycle. Images recorded within the two successive AC cycles provided evidence that the track left by the first micro-discharge influenced the propagation trajectory of consecutive streamers. Images of individual micro-discharges allowed evaluation of the luminous streamer channel diameter and its evolution along the streamer's propagation trajectory. Minimum luminous streamer channel diameters of 30 ± 6 um and 50 ± 10 um were fixed in Ar and N2, respectively. Furthermore, direct comparison between a single micro-discharge image and an image integrating many micro-discharges allows the estimation of potential errors associated with methods based on accumulating optical emission produced by many micro-discharge events.

2011 Plasma Sources Sci. Technol. 20 025010 doi: 10.1088/0963-0252/20/2/025010

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Chemical Physics, n/a. doi:10.1016/j.chemphys.2011.03.012

LIF diagnostics of hydroxyl radical in atmospheric pressure He-H2O dielectric barrier discharges

G. Dilecce, Paolo Francesco Ambrico, M. Simek and S. De Benedictis
Article Available online 21 March 2011

LIFNanostructured SiliconAbstract. In this paper we present laser induced fluorescence (LIF) measurements of OH relative density in a He-H2O atmospheric pressure dielectric barrier discharge, with an estimation of the absolute density based on the quantitative analysis of the LIF signal and on the decay of OH density in the post-discharge. The possible interference of H2O2 photo-dissociation is discussed and finally excluded. Densities of the order of 1013cm-3 have been estimated in mixtures with water vapour content ranging from 2.3 to 23 Torr partial pressure. LIF diagnostic characteristics and sensitivity in the OH case at atmospheric pressure are discussed in comparison with absorption techniques.

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