Abstract: The concept of environmental conscious materials, ecomaterials, is reviewed. It has
dispersed and recognized in the world as contributing to a sustainable society. Advanced models for
secondary materials utilization, environmental benign processes and new material recycling systems
Abstract: A unified theoretical and/or computational odd-electrons approach is suggested
for molecules, surfaces and magnetic solids making possible their consideration on the same
conceptual basis as well as on the same computational footing. The current paper presents the
approach application to the chemistry of fullerenes, carboneous nanotubes, surface science of
silicon crystal, as well as to the molecular magnetism of both solid polymerized fullerenes and
molecular crystals composed of transitional metal complexes.
Abstract: Polystyrene-polymethylmethacrylate (PS-PMMA) block copolymers are well known to
exhibit microphase separation to form a series of regular structures with local periodic arrangements
of the blocks. By developing films of PS-PMMA within topographically patterned silicon (100)
substrates (with photolithographically defined rectangular channels of depth 60 nm and widths 166
– 433 nm) these irregular arrangements form highly periodic structures where the features are
parallel to the side walls of the channels. However, the use of silicon substrates leads to problems in
processing of these films. PS-PMMA does not wet the surface, and this results in island formation
on flat substrates. On channel etched substrates this phenomena ensures that the thickness of the
films is irregular and poorly defined alignment is seen. Detailed considerations of this polymer
system suggest that feature sizes below 25 nm are not realisable. The results suggest other
copolymer systems should be studied.
Abstract: We present a study of the micro-structural changes induced in Cr-N layers by irradiation
with argon ions. The layers were deposited by reactive ion sputtering on (100) Si wafers, to a
thickness of 240-280 nm, at different nitrogen partial pressures and different substrate temperatures.
The samples were subsequently irradiated with 120 keV Ar+, to 1x1015 and 1x1016 ions/cm2.
Structural characterization was performed with Rutherford backscattering spectroscopy, x-ray
diffraction analysis and transmission electron microscopy, and we also did electrical resistivity
measurements on the samples. It has been found that the layers grow in the form of a polycrystalline
columnar structure, with a columnar width of a few tens of nm. The layer composition, Cr2N or
CrN, strongly depends on the nitrogen partial pressure during deposition. Ion irradiation induces
local micro-structural changes, formation of nano-particles and defects, though the structures retain
their polycrystalline nature. The induced crystalline defects yield an increase of electrical resistivity
after ion irradiation.
Abstract: In this paper we have analyzed the possibility of enhancing spin-polarization
performance of conventional nonmagnetic semiconductor heterostructures which rely on the
resonant tunneling mechanism. Both the bulk inversion asymmetry (BIA) and the structural
inversion asymmetry (SIA) effects are taken into account in the presented model. The aim is to
engineer nanostructures with maximal degree of spin separation in the electron tunneling current,
which might be useful in studying various spin-related phenomena in semiconductor materials.
Spin-polarization status of the current, in the devices under consideration, should be controllable by
moderate emitter-collector voltages. Additionally, the spin orbit-interactions affect the dwell times
of electrons in spin-up and spin-down states, therefore the prospects of spin-filtering in the time
domain may be considered as well.