References of "Nguyen, Ngoc Duy"
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See detailStraightforward prediction of the Ni1−xO layers stoichiometry by using optical and electrochemical measurements
Manceriu, Laura ULiege; Colson, Pierre ULiege; Maho, Anthony ULiege et al

in Journal of Physics : D Applied Physics (2017), 50

In this study, we propose a straightforward method for x determination in sub-stoichiometric nickel oxide (Ni1−xO) films prepared by ultrasonic spray pyrolysis on fluor-tin oxide (FTO) substrates by ... [more ▼]

In this study, we propose a straightforward method for x determination in sub-stoichiometric nickel oxide (Ni1−xO) films prepared by ultrasonic spray pyrolysis on fluor-tin oxide (FTO) substrates by varying the post-deposition thermal treatment. The Ni3+ concentration, the flat band potential (Φfb) and the open circuit potential (Voc) were determined by electrochemical impedance analysis in aqueous media and correlated to the transmission of Ni1−xO films. An x-ray photoelectron spectroscopy study was also performed to quantify the amount of Ni3+ in the films and compare it with the one determined by electrochemical analysis. The electrochromic behavior of the Ni1−xO films in non-aqueous electrolyte was investigated as well. With increasing Ni3+ concentration the films became more brownish and more conductive, both Voc and Φfb values increased. Calibration curves of transmission at 550 nm or open circuit potential versus carrier concentration were plotted and allowed the prediction of x in an unknown Ni1−xO sample. The Ni1−xO films characterized by the highest Ni3+ concentration have a darker colored state but lower transmission modulation, due to their reduced specific surface and increased crystallinity. [less ▲]

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See detailTransparent Electrodes Based on Silver Nanowire Networks: From Physical Considerations towards Device Integration
Bellet, Daniel; Lagrange, Mélanie; Sannicolo, Thomas et al

in Materials (2017), 10

The past few years have seen a considerable amount of research devoted to nanostructured transparent conducting materials (TCM), which play a pivotal role in many modern devices such as solar cells ... [more ▼]

The past few years have seen a considerable amount of research devoted to nanostructured transparent conducting materials (TCM), which play a pivotal role in many modern devices such as solar cells, flexible light-emitting devices, touch screens, electromagnetic devices, and flexible transparent thin film heaters. Currently, the most commonly used TCM for such applications (ITO: Indium Tin oxide) suffers from two major drawbacks: brittleness and indium scarcity. Among emerging transparent electrodes, silver nanowire (AgNW) networks appear to be a promising substitute to ITO since such electrically percolating networks exhibit excellent properties with sheet resistance lower than 10 Ω/sq and optical transparency of 90%, fulfilling the requirements of most applications. In addition, AgNW networks also exhibit very good mechanical flexibility. The fabrication of these electrodes involves low-temperature processing steps and scalable methods, thus making them appropriate for future use as low-cost transparent electrodes in flexible electronic devices. This contribution aims to briefly present the main properties of AgNW based transparent electrodes as well as some considerations relating to their efficient integration in devices. The influence of network density, nanowire sizes, and post treatments on the properties of AgNW networks will also be evaluated. In addition to a general overview of AgNW networks, we focus on two important aspects: (i) network instabilities as well as an efficient Atomic Layer Deposition (ALD) coating which clearly enhances AgNW network stability and (ii) modelling to better understand the physical properties of these networks. [less ▲]

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See detailFlux penetration in a superconducting film partially capped with a conducting layer
Brisbois, Jérémy ULiege; Gladilin, V. N.; Tempere, J. et al

in Physical Review B (2017), 95

The influence of a conducting layer on the magnetic flux penetration in a superconducting Nb film is studied by magneto-optical imaging. The metallic layer partially covering the superconductor provides ... [more ▼]

The influence of a conducting layer on the magnetic flux penetration in a superconducting Nb film is studied by magneto-optical imaging. The metallic layer partially covering the superconductor provides an additional velocity-dependent damping mechanism for the flux motion that helps protecting the superconducting state when thermomagnetic instabilities develop. If the flux advances with a velocity slower than w = 2/µ0σt, where σ is the cap layer conductivity and t is its thickness, the flux penetration remains unaffected, whereas for incoming flux moving faster than w, the metallic layer becomes an active screening shield. When the metallic layer is replaced by a perfect conductor, it is expected that the flux braking effect will occur for all flux velocities. We demonstrate this effect by investigating Nb samples with a thickness step. Some of the observed features, namely the deflection and the branching of the flux trajectories at the border of the thick centre, as well as the favoured flux penetration at the indentation, are reproduced by time-dependent Ginzburg-Landau simulations. [less ▲]

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See detailCation-doped Cu2O as a transparent p-type semiconducting oxide with enhanced performances: A comparison between strontium and magnesium incorporation
Avelas Resende, João ULiege; Brochen, Stéphane; Bergerot, Laurent et al

Conference (2016, October)

In the group of semiconducting metallic oxides, cuprous oxide (Cu2O) presents promising electrical and manufacturing features for a variety of applications as p-type transparent material suitable in the ... [more ▼]

In the group of semiconducting metallic oxides, cuprous oxide (Cu2O) presents promising electrical and manufacturing features for a variety of applications as p-type transparent material suitable in the domains of transparent electronics and photovoltaic cells. However Cu2O suffers from optical and electrical limitations, due to a relatively small bandgap of 2.17 eV and a fairly high resistivity (> 102 Ω.cm) in intrinsic thin films at room temperature. In this work, we successfully doped Cu2O thin films with different divalent cations, namely Sr and Mg, by metal-organic chemical vapour deposition. We compared the effects of each element on crystallographic structure, films morphology, electronic transport and optical transmittance. In both cases, the presence of the cation contributed to a higher stability of the Cu2O phase, reducing the appearance of CuO parasitic phase. Nevertheless, a SrCO3 phase was detected in the Sr doped system. In terms of electrical properties, the incorporation of Sr, up to 16%, reduced the resistivity down to 1Ω.cm, with a mobility of 16 cm2.V-1.s-1. Moreover, the incorporation of strontium also leads to the emergence of a with a deep acceptor level located around EA = 278 ± 21 meV above the top of the valence band. The concentration of this deep acceptor level, attributed to simple copper vacancies, drastically increases with the strontium content, due to a decrease of its formation energy. The effect on optical transmittance could not be detected. The Mg-doped Cu2O thin films were monophasic and showed a higher resistivity of 6.6 Ω.cm at an Mg concentration of 17%, due to the lower mobility, 1 cm2.V-1.s-1. Although, the presence of this dopant contributes for the highest charge-carrier density observed in this work, up to 8x1017 cm-3. As in the Sr case, this can be explained by a simple copper vacancy doping mechanism assisted by cation incorporation. Additionally, a slight increase of transparency is observed when compared to intrinsic Cu2O. The control of carrier concentration and mobility values by dopant concentration, as well as the improvements in phase stability and transparency are key factors for the application of this versatile p-type oxide in transparent electronics and solar cells applications. [less ▲]

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See detailDirect Imaging of the Onset of Electrical Conduction in Silver Nanowire Networks by Infrared Thermography: Evidence of Geometrical Quantized Percolation
Sannicolo, Thomas; Munoz-Rojas, David; Nguyen, Ngoc Duy ULiege et al

in Nano Letters (2016), 16

Advancement in the science and technology of random metallic nanowire (MNW) networks is crucial for their appropriate integration in many applications, including transparent electrodes for optoelectronics ... [more ▼]

Advancement in the science and technology of random metallic nanowire (MNW) networks is crucial for their appropriate integration in many applications, including transparent electrodes for optoelectronics and transparent film heaters. We have recently highlighted the discontinuous activation of efficient percolating pathways (EPPs) for networks having densities slightly above the percolation threshold. Such networks exhibit abrupt drops of electrical resistance when thermal or electrical annealing is performed, giving rise to a “geometrically quantized percolation”. In this letter, Lock-in Thermography (LiT) is used to provide visual evidence of geometrical quantized percolation: when low voltage is applied to the network, individual “illuminated pathways” can be detected and new branches get highlighted as the voltage is incrementally increased. This experimental approach has allowed us to validate our original model and map the electrical and thermal distributions in silver nanowire (AgNW) networks. We also study the effects of electrode morphology and wire dimensions on quantized percolation. Furthermore we demonstrate that the network failure at high temperature can also be governed by a quantized increase of the electrical resistance, corresponding to the discontinuous destruction of individual pathways (anti-percolation). More generally, we demonstrate that LiT is as a promising tool for the detection of conductive sub-clusters, as well as hot spots in AgNW networks. [less ▲]

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See detailStudy of the effect of thin ALD oxide coatings on the stability of silver nanowire based transparent electrodes
Aghazadehchors, Sara; Nguyen, Viet; Lagrange, Mélanie et al

Poster (2016, October)

Current research on new Transparent Conductive Materials focuses on emerging materials such as carbon-based materials, graphene or metallic nanowire networks. The latter concern mainly silver nanowires ... [more ▼]

Current research on new Transparent Conductive Materials focuses on emerging materials such as carbon-based materials, graphene or metallic nanowire networks. The latter concern mainly silver nanowires (AgNW). Although AgNW networks seem to approach ITO values in terms of optical transparency and electrical sheet resistance, (90% and 10 Ω/sq respectively) [1], overcoming a rather poor thermal and electrical stability still remains a challenge. While most device fabrication processes require thermal annealing steps to optimize their electrical properties, heating can modify AgNW network morphology. Moreover, when used as transparent heaters, an electrical current induces specimen heating (due to Joule effect) and then imposing AgNW network to be resistant to heat. One way to improve thermal stability of AgNW networks is to use a thin layer of a passivating metal oxide (such as ZnO or TiO2) which induces stability improvements [2]. So far, our group has studied the effect of a thin layer of TiO2 deposited by ALD on the thermal and electrical stability of AgNWs networks. Our studies show that even a TiO2 layer as thin as 5 nm can lead to an extension of thermal stability from 270 °C to 420 °C. The oxide coating also increases the value of the electrical failure voltage. This stability enhancement comes with nearly no change in optical transparency (less than 1%). Currently we are replacing the ALD deposition method with a new approach called Spatial ALD (SALD). This technique does not require vacuum, it is much faster than conventional ALD and is easily scalable [3]. Here we will present a comprehensive study of the effect of deposition parameters, passivation film thickness on the electrical and optical properties of AgNWs based transparent electrodes. Optimized parameters will allow the integration in devices such as transparent heaters. We will demonstrate that adding a passivation layer increases the breakdown voltage, making the devices stable at higher voltage or temperature. References: [1] Lagrange, M., Langley, D. P., Giusti, G., Jiménez, C., Bréchet, Y., & Bellet, D. (2015). Optimization of silver nanowire-based transparent electrodes: effects of density, size and thermal annealing. Nanoscale, 7(41), 17410- 17423. [2] Kim, A., Won, Y., Woo, K., Kim, C. H., & Moon, J. (2013). Highly transparent low resistance ZnO/Ag nanowire/ZnO composite electrode for thin film solar cells. ACS nano, 7(2), 1081-1091. [3] Muñoz-Rojas, D., & MacManus-Driscoll, J. (2014). Spatial atmospheric atomic layer deposition: a new [less ▲]

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See detailTransparent electrodes based on silver nanowire networks: from fundamental aspects to integration into device
Sannicolo, T.; Lagrange, M.; Xian, S. et al

Conference (2016, October)

The past few years have seen a considerable amount of research devoted to nanostructured transparent conducting materials which play a pivotal role in many modern devices such as: solar cells, flexible ... [more ▼]

The past few years have seen a considerable amount of research devoted to nanostructured transparent conducting materials which play a pivotal role in many modern devices such as: solar cells, flexible light-emitting devices, touch screens and flexible transparent thin film heaters. Metallic nanowire networks have recently been a heavily researched subject. Currently, the most commonly used material for such applications is Tin-doped Indium oxide (ITO). Although ITO exhibits very good physical properties, indium scarcity and brittleness have prompted the search for alternative materials. Among emerging transparent electrodes, silver nanowire (AgNW) networks appear as a promising substitute to ITO since these percolating networks exhibit excellent properties with sheet resistance of a few Ω/sq and optical transparency of 90%, fulfilling the requirements for many applications. It also shows very good electro-mechanical properties. In addition, the fabrication of these electrodes involves low-temperature process steps and upscaling methods, thus making them very appropriate for future use as TE for flexible devices. Our research is focused on the fundamental understanding of the physical phenomena taking place at the scales of both the network (macroscale) and the NW-to-NW junctions (nanoscale), and on the ability of AgNW networks to be integrated as transparent electrodes for different applications. In-situ electrical measurements performed during optimisation process such as thermal annealing provide useful information regarding the activation process of the junctions. This contribution aims at presenting a short overview of the main properties and applications of metallic nanowire networks, as well as the integration in devices. [less ▲]

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See detailFlexible Transparent Electrodes based on Silver Nanowire Networks: Nanoscale Characterisation, Electrical Percolation, and Integration into Devices
Sannicolo, T.; Lagrange, M.; Xian, S. et al

Conference (2016, September)

The most efficient and widely used transparent conducting material (TCM) is currently indium tin oxide (ITO). However the indium scarcity associated to the lack of flexibility of ITO as well as relatively ... [more ▼]

The most efficient and widely used transparent conducting material (TCM) is currently indium tin oxide (ITO). However the indium scarcity associated to the lack of flexibility of ITO as well as relatively high cost of fabrication has prompted the search for alternative low cost and flexible materials. Among emerging transparent electrodes (TEs), silver nanowire (AgNW) networks appear as a promising substitute to ITO since these percolating networks exhibit high flexibility and excellent optoelectronic properties [1], with sheet resistance of a few Ω/sq and optical transparency of 90%, fulfilling the requirements for many applications such as solar cells, OLED displays, transparent heaters, or radio-frequency (RF) antennas and transparent shielding [2]. In addition, the fabrication of these electrodes involves low-temperature process steps and upscaling methods, thus making them very appropriate for future use as TE for flexible devices. Our research is focused on the fundamental understanding of the physical phenomena taking place at the scales of both the network (macroscale) and the NW-to- NW junctions (nanoscale), and on the ability of AgNW networks to be integrated as transparent electrodes for flexible optoelectronic and RF devices. In-situ electrical measurements performed during optimisation process such as thermal annealing and/or chemical treatments provide useful information regarding the activation process of the junctions [3]. Besides, nano-characterisation techniques such as Transmission Electron Microscopy (TEM) and ultramicrotomy help visualizing the physical phenomena involved in the diffusion of silver atoms to create well-sintered junctions. At the network’s scale, our ability to distinguish the nanowires taking part in the electrical conduction (“electrical percolating pathways”) from the inactive nanowires is a critical issue for the applications. By combining experimental and simulation studies, a discrete activation process of efficient percolating pathways through the network was evidenced. In the case where the network density is close to the percolation threshold and when low voltage is applied, individual “illuminated” pathways can be detected through the network while new branches get activated as soon as the voltage is increased. Here we will present our results on the study of AgNW networks at the macro and nano scales described above and will correlate it with the overall performance/characteristics of the networks. We will also present results on the integration of optimized AgNW networks into functional devices. [1] D.P. Langley, G. Giusti, C. Mayousse, C. Celle, D. Bellet, J.-P. Simonato, Nanotechnology, 24, 452001, (2013). [2] C. Celle, C. Mayousse, E. Moreau, H. Basti, A. Carella and J.-P. Simonato, Nano Res. 5, 427, (2012). [3] M. Lagrange, D.P. Langley, G. Giusti, C. Jimenez, Y. Bréchet, D. Bellet, Nanoscale 7, 17410, (2015). [less ▲]

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See detailMagnesium-doped cuprous oxide (Mg:Cu2O) thin films as a transparent p-type semiconductor
Avelas Resende, João ULiege; Jimenez, Carmen; Nguyen, Ngoc Duy ULiege et al

in Physica Status Solidi A. Applications and Materials Science (2016), 213(9), 22962302

The lack of a successful p-type transparent semiconductor delays the future implementation of transparent electron- ics. In the group semiconducting compounds, cuprous oxide (Cu2O) presents promising ... [more ▼]

The lack of a successful p-type transparent semiconductor delays the future implementation of transparent electron- ics. In the group semiconducting compounds, cuprous oxide (Cu2O) presents promising electrical and manufacturing features that establish it as a suitable candidate for p-type transparent semiconductors. However, high absorbance in the visible range reduces its application practical devices. In this work, we achieved the incorporation of magnesium in cuprous oxide grown by aerosol-assisted metal-organic chemical vapour deposition. The fabricated doped thin films reached up to 17% of magnesium, resulting in morphology changes. Electrical resistivity was reduced down to values as low as 6.6 Vcm, due to the increase of charge-carrier density. The optical transparency was enhanced compared to intrinsic cuprous oxide. [less ▲]

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See detailImprinting superconducting vortex footsteps in a magnetic layer
Brisbois, Jérémy ULiege; Motta, Maycon; Avila Osses, Jonathan ULiege et al

in Scientific Reports (2016), 6

Local polarization of a magnetic layer, a well-known method for storing information, has found its place in numerous applications such as the popular magnetic drawing board toy or the widespread credit ... [more ▼]

Local polarization of a magnetic layer, a well-known method for storing information, has found its place in numerous applications such as the popular magnetic drawing board toy or the widespread credit cards and computer hard drives. Here we experimentally show that a similar principle can be applied for imprinting the trajectory of quantum units of flux (vortices), travelling in a superconducting film (Nb), into a soft magnetic layer of permalloy (Py). In full analogy with the magnetic drawing board, vortices act as tiny magnetic scribers leaving a wake of polarized magnetic media in the Py board. The mutual interaction between superconducting vortices and ferromagnetic domains has been investigated by the magneto-optical imaging technique. For thick Py layers, the stripe magnetic domain pattern guides both the smooth magnetic flux penetration as well as the abrupt vortex avalanches in the Nb film. It is however in thin Py layers without stripe domains where superconducting vortices leave the clearest imprints of locally polarized magnetic moment along their paths. In all cases, we observe that the flux is delayed at the border of the magnetic layer. Our findings open the quest for optimizing magnetic recording of superconducting vortex trajectories. [less ▲]

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See detailPolar interface phonons in ionic toroidal systems
Nguyen, Ngoc Duy ULiege; Evrard, Roger ULiege; Stroscio, Michael

in Journal of Physics : Condensed Matter (2016), 28(34), 345301

We use the dielectric continuum model to obtain the polar (Fuchs–Kliewer like) interface vibration modes of toroids made of ionic materials either embedded in a different material or in vacuum, with ... [more ▼]

We use the dielectric continuum model to obtain the polar (Fuchs–Kliewer like) interface vibration modes of toroids made of ionic materials either embedded in a different material or in vacuum, with applications to nanotoroids specially in mind. We report the frequencies of these modes and describe the electric potential they produce. We establish the quantum-mechanical Hamiltonian appropriate for their interaction with electric charges. This Hamiltonian can be used to describe the effect of this interaction on different types of charged particles either inside or outside the torus. [less ▲]

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See detailNote on the numerical solution of the scalar Helmholtz equation in a nanotorus with uniform Dirichlet boundary conditions
Nguyen, Ngoc Duy ULiege; Evrard, Roger ULiege; Stroscio, Michael

E-print/Working paper (2016)

This note describes the solution of the Helmholtz equation inside a nanotorus with uniform Dirichlet boundary conditions. The eigenfunction symmetry is discussed and the lower-order eigenvalues and ... [more ▼]

This note describes the solution of the Helmholtz equation inside a nanotorus with uniform Dirichlet boundary conditions. The eigenfunction symmetry is discussed and the lower-order eigenvalues and eigenfunctions are shown. The similarity with the case of a long cylinder and with that of the vibrations of a circular elastic membrane is discussed. This similarity is used to propose a classification scheme of the eigenfunctions based on three indices. [less ▲]

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See detailMagnetic flux penetration in Nb superconducting films with lithographically defined micro-indentations
Brisbois, Jérémy ULiege; Adami, Obaïd-Allah ULiege; Avila Osses, Jonathan ULiege et al

in Physical Review B (2016), 93(5), 054521

We present a thorough investigation by magneto-optical imaging of the magnetic flux penetration in Nb thin films with lithographically defined border indentations. We demonstrate that discontinuity lines ... [more ▼]

We present a thorough investigation by magneto-optical imaging of the magnetic flux penetration in Nb thin films with lithographically defined border indentations. We demonstrate that discontinuity lines (d-lines), caused by the abrupt bending of current streamlines around the indentations, depart from the expected parabolic trend close to the defect and depend on the shape and size of the indentation as well as on the temperature. These findings are backed up and compared with theoretical results obtained by numerical simulations and analytical calculations highlighting the key role played by demagnetization effects and the creep exponent n. In addition, we show that the presence of nearby indentations and submicrometer random roughness of the sample border can severely modify the flux front topology and dynamics. Strikingly, in contrast to what has been repeatedly predicted in the literature, we do not observe that indentations act as nucleation spots for flux avalanches, but they instead help to release the flux pressure and avoid thermomagnetic instabilities. [less ▲]

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See detailPolar surface phonons in nanotori
Nguyen, Ngoc Duy ULiege; Evrard, Roger; Stroscio, Michael A.

in Journal of Physics: Condensed Matter (2016)

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See detailAnalysis of the time-dependent electrical current in reverse-biased p-GeSn/n-Ge mesa diodes
Baert, Bruno ULiege; Gupta, Somya; Gencarelli, Federica et al

Poster (2015, September)

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See detailTransparent electrodes based on silver nanowire networks: physical properties and potential applications
Lagrange, Mélanie; Sannicolo, Thomas; Langley, Daniel et al

Conference (2015, September)

Transparent electrodes (TE) constitute a key component of optoelectronic devices such as solar cells, efficient organic light-emitting diodes (OLEDs), touch screens. Currently the most widely used TE is ... [more ▼]

Transparent electrodes (TE) constitute a key component of optoelectronic devices such as solar cells, efficient organic light-emitting diodes (OLEDs), touch screens. Currently the most widely used TE is indium tin oxide (ITO), which offers low resistivity and high transparency in the visible. However the scarcity of indium and the lack of flexibility of ITO has prompted the search for alternative materials. Among emerging TE, metallic nanowire (NW) networks appear to be a promising solution since these percolating networks exhibit excellent properties with sheet resistance of a few Ω/sq and optical transparency of 90%, fulfilling the requirements for many applications. In addition, the fabrication of these electrodes involves low-temperature process steps and upscaling methods, thus making them very appropriate for future use as TE for flexible devices. Our research is focused on both the fabrication of TE based on silver NW and the optimization of their physical properties, using experimental and modelling approaches. The influence of several key parameters such as network density, silver NW dimensions as well as thermal annealing, on the networks physical properties is thoroughly explored. A comprehensive understanding of the relationship between design and main physical properties of these promising nanostructured networks will be presented. Their stability will also be discussed. Finally, we will also show that such TE can be very well adapted as transparent heaters. [less ▲]

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See detailMagnesium-doped Cuprous Oxide (Mg:Cu2O) thin films as a transparent p-type semiconductor oxide
Avelas Resende, João ULiege; Nguyen, Ngoc Duy ULiege; Deschanvres, Jean-Luc et al

Poster (2015, September)

Oxide electronics is an important emerging area, notably for the development of transparent thin film transistors (TFTs) and other complex electronic circuits. The successful application of n-type oxides ... [more ▼]

Oxide electronics is an important emerging area, notably for the development of transparent thin film transistors (TFTs) and other complex electronic circuits. The successful application of n-type oxides to TFTs has motivated the interest in p-type oxide based semiconductors, also to be applied to TFTs or to complementary metal-oxide semiconductor (CMOS) technology. However, until now there is a lack of p-type oxide semiconductors with performance similar to that of n-type oxide. Among the different metallic oxides, Cu (I)-based oxides exhibit one of the lowest ionic character. These compounds are therefore one of the most promising candidates as p-type transparent semiconductors.Nevertheless, the band gap of 2,17eV is modest for transparent electronics applications, since the transmittance of Cu2O films is low on the visible part of the light spectrum. The incorporation of cations with large radii than Cu has been proposed as a way to achieve a higher band gap, by diminishing of three-dimensional Cu-Cu interactions, only possible with larger cations than Cu+. Therefore, cation doped Cu2O thin films were grown by metal-organic chemical vapor deposition (MOCVD). The three doping elements studied (Sr2+, Sn2+ and La3+) were selected having in account theoretical predictions for the band structure and the deposition conditions of Cu2O. The study focus on thin films growth optimization combined with electronic transport analysis and optical transmittance measurements. [less ▲]

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See detailElectrical characterization of p-GeSn/n-Ge diodes with interface traps under dc and ac regimes
Baert, Bruno ULiege; Gupta, Somya; Gencarelli, Federica et al

in Solid-State Electronics (2015), 110

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See detailAn atomic layer deposition approach to ultra-shallow doping of silicon
Nguyen, Ngoc Duy ULiege

Conference (2015, May)

One criticial requirement for the boosting of silicon metal-oxide-semiconductor field-effect transistor (FET) performances in ultra large scale integration is the aggressive scaling of the source and ... [more ▼]

One criticial requirement for the boosting of silicon metal-oxide-semiconductor field-effect transistor (FET) performances in ultra large scale integration is the aggressive scaling of the source and drain extension junctions. As electronic devices are reaching sub-10 nm junction depths, the achievement of low sheet resistance becomes more challenging and raises questions about the underlying physical limitations to the electrical activation of dopant atoms in ultra-thin films. Moreover, the degradation of the junction quality by non-trivial effects related to implantation damage when an amorphization process step is used to minimize dopant channeling, poses serious difficulties to doping techniques such as beamline ion implantation. Finally, in the case of 3D devices such as multi-gate FETs, the constraint of doping conformality induces additional challenges that can not be addressed by ion implantation, which suffers from shadowing effects for patterns with high fin density. Consequently, there is a strong need of novel doping strategies for both planar and non-planar devices. On the one hand, potential alternatives such as atomic layer doping (ALD) and plasma immersion ion implantation have already shown promising results [1, 2]. On the other hand, sub-melt millisecond anneal is considered as the method of choice for dopant activation whereas classical spike rapid thermal annealing results in excessive dopant diffusion and limited electrical activation. In this work, we investigated the properties of ultra shallow junctions fabricated by the combination of ALD and sub-melt laser annealing (LA). We show that low-resistance p-type and n-type junctions compatible with current device technologies can be both manufactured using ALD and LA. In the case of ALD with boron, we demonstrate that junctions with high electrical activation level, strongly reduced diffusion tails after anneal and excellent conformality can be obtained [1, 3]. In contrast, for n-type doping, electrical deactivation of a large part of the in-diffused dopants was observed and attributed to energetically-favorable dopant-vacancy cluster formation [4, 5]. However, we found that the sheet resistance could be reduced by using an alternative capping scheme. The improvement is explained by the combination of both an epitaxial cap and the atomic dopant layer. [1] N. D. Nguyen et al., Thin Solid Films 518, 48 (2010) [2] S. Takeuchi et al., ECS Trans. 16, 495 (2008) [3] S.-Y. Park et al., IEEE Electron Device Letters 30, 1173 (2009) [4] R. Pinacho et al., Appl. Phys. Lett. 86, 252103 (2005) [5] P. M. Voyles et al., Phys. Rev. Lett. 91, 125505 (2003) [less ▲]

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