Surface Charge Transfer Doping Enabled High Performance Optoelectronic Devices Based on 2D Materials
Wei Chen, National University of Singapore, Singapore
Two-dimensional (2D) layered materials like graphene and transition metal dichalcogenides (TMDs) have been considered as promising building blocks for the next generation nanoelectronic devices, showing great potentials to extend the scaling limits existing in silicon based complementary metal-oxide-semiconductor field-effect-transistors (CMOS-FET) as well as to serve as a high mobility alternative to organic semiconductors for flexible electronic and optoelectronic devices. As one-atomic or a few atomic thin layers, the interface plays essential role in determining the performance of 2D materials based devices, such as charge injection/collection at metal/2D interfaces, charge carrier traps at the dielectric/2D interfaces, etc. Without precise control of the surface and interface properties, many 2D materials based devices will not function properly.
In this talk, I will summarize and discuss our recent work for interface engineered 2D phosphorene and TMDCs based field-effect-transistors (FETs) and photo-transistors, through the combination of in-situ FET device evaluation and photoelectron spectroscopy investigation. We will particularly emphasize on the electron and hole doping effect on the transport properties and optoelectronic response of phosphorene devices.
Laser Direct Writing and sintering for flexible electronic applications
Ioanna Zergioti, National Technical University of Athens, Greece
Current technological trends require the precise deposition of highly resolved features, in a direct writing approach which preserve their structural and electronic properties upon transfer, while increasing the number of components that can be integrated in a single device. Over the past decade, printed electronics technology has evolved and is now used in applications such as flexible screens, intelligent labels and packaging. Among the printing techniques, Laser-induced forward transfer (LIFT) technique is capable of printing electrical circuits quite inexpensively and quickly. At the same time, this technique is environmentally friendly and has no restrictions in terms of viscosity. In this work we highlight the newest trends of LIFT manufacturing for the development of a variety of components with electronic, optoelectronic and sensing functionality such as RFID antennas, RF transmission lines, organic thin-film transistors, metallic interconnects, circuits defects repairing and chemical sensors.
At the same time, the increasingly demanding requirements have highlighted the need of a more thorough, all-embracing research regarding the rheological characteristics of the printable fluids, their jetting dynamics and their electrical, post-sintering properties, that will define the process' reliability, aiming towards its industrialization.
In this work, we initially employed a high-speed imaging set up in order to investigate the liquid jet's propagation formed during the printing procedure. Different Ag nanoparticle inks are studied and compared, over a wide range of viscosities and two different cases of surface tension. Jet dynamics analysis gives insight into the initial conditions for the spreading process of the printed droplet on the receiver surface. The initial phases of the spreading process are largely influenced by the impact speed, the jet diameter just before impact and the break time during the wetting phase, the rheological properties of the ink, especially surface tension, combined with the wetting properties of the receiver substrate will determine the final spreading and shape of the printed droplet. Following printing process analysis, a systematic experimental and theoretical investigation of the laser sintering was conducted on printed micro-patterns comprising Ag and Cu viscous nanoparticle inks. The main goal of this investigation is the determination of the optimal processing parameters for the fabrication of highly conductive Ag and Cu patterns on polymeric substrates with current applications in organic and large area electronics.
Biomolecules on metal surfaces, from UHV to the liquid phase
The adsorption and self-assembly of peptides on metallic surfaces is a key step in the design and construction of functional materials for, as examples, i) biocompatible materials or ii) biofilm construction on any type of material in a natural environment ; some biomolecules, in particular peptides, are indeed frequently utilized to control the reactivity or passivation of solid materials. It is thus crucial both to understand the interaction of biomolecules with solid surfaces and, deduce ways of immobilizing them, in a controlled geometry.
In this presentation, we will highlight several examples where a basic and surface science approach has led to unravel the adsorption mode of short peptides on metal, nanostructured, surfaces; similar experiments were conducted in an aqueous phase, opening the possibility to apply other characterization techniques… and showing unexpected behaviours, induced by the presence of water.We will see how the mode of adsorption and geometry of a peptide may govern the growth of single or multilayers, even some times surface corrosion, and how adsorption of peptide enantiomers can imprint chirality and induce enantioselective recognition, or yield anti-adhesive surfaces.
V. HUMBLOT, F. TIELENS, N. LUQUE, H.HAMPARTSOUMIAN, C.METHIVIER, C.M. PRADIER
Characterization of the 2-Dimensional Chiral Self-Assemblies L- & D-Methionine on Au(111)
Langmuir, 2014, 2014, 30 (1), 203–212
DOMINIQUE COSTA, CLAIRE-MARIE PRADIER, FREDERIK TIELENS, LETIZIA SAVIO
Surface Science Reports, Volume 70, 2015, 449-553
CHRISTOPHE MÉTHIVIER, VINCENT HUMBLOT, AND CLAIRE-MARIE PRADIER
L-Methionine adsorption on Cu(110), binding and geometry of the amino acid as a function of coverage
Surface Science, 2015, 632, 88-92
CRUEGEL, H., METHIVIER, C., PRADIER, C.M., HUMBLOT, V
Surface Chirality of Gly-Pro Dipeptide Adsorbed on a Cu(110) Surface.
Chirality, 2015, 27, 411-416
D. COSTA, L. SAVIO, AND C-M. PRADIER
Adsorption of Amino Acids and Peptides on Metal and Oxide Surfaces in Water Environment: A Synthetic and Prospective Review
J. Phys. Chem. B, 2016, 120 (29), pp 7039–7052
METHIVIER, CHRISTOPHE; HUMBLOT, VINCENT; PRADIER, CLAIRE-MARIE
UHV Deposition of the Gly-Pro Dipeptide on Cu(110) by Sublimation or Electrospray Ionization"
J. Phys. Chem. C, 2016, 120 (48), pp 27364–27368. DOI: jp-2016-09173x
Totani, Roberta; Méthivier, Christophe; Cruguel, Hervé; Pradier, Claire-Marie; Humblot, Vincent
Deciphering the Adsorption Mechanisms of RGD Subunits: L-Aspartic Acid on Cu(110)"
J. Phys. Chem. C 2017, 121 (29), 15842–15850 : jp-2017-049488.R2