Subscribe to the gold package and get unlimited access to Shamra Academy
Register a new userTransport properties of copper phthalocyanine based organic electronic devices
117
0
0.0
(
0
)
Ask ChatGPT about the research
No Arabic abstract
Ambipolar charge carrier transport in Copper phthalocyanine (CuPc) is studied experimentally in field-effect transistors and metal-insulator-semiconductor diodes at various temperatures. The electronic structure and the transport properties of CuPc attached to leads are calculated using density functional theory and scattering theory at the non-equilibrium Greens function level. We discuss, in particular, the electronic structure of CuPc molecules attached to gold chains in different geometries to mimic the different experimental setups. The combined experimental and theoretical analysis explains the dependence of the mobilityand the transmission coefficient on the charge carrier type (electrons or holes) and on the contact geometry. We demonstrate the correspondence between our experimental results on thick films and our theoretical studies of single molecule contacts. Preliminary results for fluorinated CuPc are discussed.
rate research
Read More
The magnetic and transport properties of the metal phthalocyanine (MPc) and F$_{16}$MPc (M = Sc, Ti, V, Cr, Mn, Fe, Co, Ni, Cu, Zn and Ag) families of molecules in contact with S-Au wires are investigated by density functional theory within the local density approximation, including local electronic correlations on the central metal atom. The magnetic moments are found to be considerably modified under fluorination. In addition, they do not depend exclusively on the configuration of the outer electronic shell of the central metal atom (as in isolated MPc and F$_{16}$MPc) but also on the interaction with the leads. Good agreement between the calculated conductance and experimental results is obtained. For M = Ag, a high spin filter efficiency and conductance is observed, giving rise to a potentially high sensitivity for chemical sensor applications.
The recent observation of fractional quantum Hall effect in high mobility suspended graphene devices introduced a new direction in graphene physics, the field of electron-electron interaction dynamics. However, the technique used currently for the fabrication of such high mobility devices has several drawbacks. The most important is that the contact materials available for electronic devices are limited to only a few metals (Au, Pd, Pt, Cr and Nb) since only those are not attacked by the reactive acid (BHF) etching fabrication step. Here we show a new technique which leads to mechanically stable suspended high mobility graphene devices which is compatible with almost any type of contact material. The graphene devices prepared on a polydimethylglutarimide based organic resist show mobilities as high as 600.000 cm^2/Vs at an electron carrier density n = 5.0 10^9 cm^-2 at 77K. This technique paves the way towards complex suspended graphene based spintronic, superconducting and other types of devices.
The perylene-3,4,9,10-tetracarboxylic-dianhydride (PTCDA) and 1,4,5,8-naphthalene-tetracaboxylic-dianhydride (NTCDA) are planar pi-stacking organic molecules that have been shown to be excellent model compounds for studying the growth and optoelectronic properties of organic semiconductor thin films, particularly organic diodes. Some observations have shown that this molecules, particularly PTCDA a brick-like shaped molecule easily forms well-ordered films on various substrates due to its unique crystal structure which is characterized by flat lying molecules In this work we will explore some energetic and optical characteristics such as heats of formation, optic GAP energies, electronic transitions and others of novel tow layer systems of alternate layers of PTCDA and NTCDA by means of the semiempirical methods Parametric Model 3 (PM3) and Zerners Intermediate Neglect of Differential Overlap (ZINDO/S) in Configuration Interaction mode.
In this paper we review the theory of silicon nanowires. We focus on nanowires with diameters below 10 nm, where quantum effects become important and the properties diverge significantly from those of bulk silicon. These wires can be efficiently treated within electronic structure simulation methods and will be among the most important functional blocks of future nanoelectronic devices. Firstly, we review the structural properties of silicon nanowires, emphasizing the close connection between the growth orientation, the cross-section and the bounding facets. Secondly, we discuss the electronic structure of pristine and doped nanowires, which hold the ultimate key for their applicability in novel electronic devices. Finally, we review transport properties where some of the most important limitations in the performances of nanowire-based devices can lay. Many of the unique properties of these systems are at the same time defying challenges and opportunities for great technological advances.
Since the discovery of graphene -a single layer of carbon atoms arranged in a honeycomb lattice - it was clear that this truly is a unique material system with an unprecedented combination of physical properties. Graphene is the thinnest membrane present in nature -just one atom thick- it is the strongest material, it is transparent and it is a very good conductor with room temperature charge mobilities larger than the typical mobilities found in silicon. The significance played by this new material system is even more apparent when considering that graphene is the thinnest member of a larger family: the few-layer graphene materials. Even though several physical properties are shared between graphene and its few-layers, recent theoretical and experimental advances demonstrate that each specific thickness of few-layer graphene is a material with unique physical properties.
Log in to be able to interact and post comments
comments
Fetching comments
Sign in to be able to follow your search criteria
