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A combination of scanning electron microscopy and atomic force microscopy was used to perform surface analysis of GeSbSe chalcogenide thin films grown at normal incidence and at four different oblique evaporation angles. The findings reveal that notable increase of roughness and surface area with increasing evaporation oblique angle could have a significant effect on the development of optical sensors.

The x-ray diffraction (XRD) and second harmonic generation are used to examine the correlation between heat-treatment temperature for crystallization and orientation of surface crystalline phase in 30BaO-15Ti[O.sub.2]-55Ge[O.sub.2] (BTG55) crystallized glass. The results have provided the guideline for the BTG55 crystallized glass with a large nonlinear optical susceptibility that has originated from the designed crystallized structure.

The amorphous films of the GeTe(1-x)-Sb2Te3(x) pseudobinary compounds [0(less than or equal to)x(less than or equal to)2/3], which are obtained by substituting Sb2Te2 for GeTe, are crystallized into simple NaCl-type structures, regardless of their compositions, through instantaneous laser irradiation. The results have shown that when the ratio of Sb2Te3 increases, vacancies are intrinsically generated, which makes sure that valence electrons provided by adjacent Ge/Sb and Te atoms remain constant to preserve crystal chemical stability.

Ba(sub 8)Ga(sub 16)Si(sub x)Ge(30-x) were synthesized and their structural and electrical properties compared to those of similar type-I clathrates (Ba(sub 8)Ga(sub 16)Si(sub x)Ge(30-x)and Sr(sub 8)Ga(sub 16)Si(sub x)Ge(30-x)). The increasing Si content is accompanied by a slight increase in the absolute Seeback coefficient even as the carrier concentration increases and the resistivity decreases.

Density functional theory (DFT) at the hybrid B3LYP level is applied to the polyhedral boranes BnH(sub n)(super z) (n=8 and 11, z=-2, -4, and -6) for comparison with isoelectronic germanium clusters Ge(sub n)(super z). The energy differences between the global minima and other higher energy borane structures are much larger relative to the case of the corresponding bare germanium clusters.

A terahertz laser concept based on intersubband transitions of holes under vertical transport in crossed electric and magnetic fields in a planar periodically doped p-Ge/Ge structure is presented. Population inversion and gain sufficient for laser operation are expected up to 77 K and test structures grown by chemical-vapor deposition shows feasibility of producing the device with sufficient active thickness to allow quasioptical electrodynamic cavity solutions.

The crystal structures of two hydrazinium-based germanium(IV) and tin(IV) selenide salts are determined. Substantial hydrogen bonding exists among the hydrazine/hydrazinium molecules as well as between the hydrazinium cations and the selenide anions.

Density functional theory (DFT) at the hybrid B3LYP level is applied to the germanium clusters Ge(sub11)(super z) starting from eight different initial configurations. DFT studies predicted an interesting D(sub 5h) centered pentagonal prismatic structure for Ge(sub 11)(super 2+) and isoelectronic metal clusters.

The study investigated the adsorption of pyrimidine onto Ge(100) surface using real-time scanning tunneling microscopy (STM), temperature-programmed desorption (TPD), and density-functional theory (DFT), calculation. It concluded that the adsorbed pyrimidine molecules are titled about 40 degree with respect to the Ge surfaces, and through a Lewis acid-base reaction form bridges between the down-Ge atoms of neighboring Ge diner rows by double Ge-N dative bonding without loss of aromaticity.

The synthesis and detailed characterization, including X-ray crystallography, of the first germanium(II) compound with a radical-anionic ligand is described. The electron spin resonance spectroscopic data indicate that the spin density in is distributed over the ligand (N and H nuclei) as well as over germanium and chlorine atoms.

The structures of trimethylchlorogermane ((CH3)3GeCl) and trimethylbromogermane ((CH3)GeBr) are determined with the help of gas-phase electron diffraction (GED) augmented by the results from ab initio calculations. The results from the ab initio calculations indicate that these molecules have C3v symmetry and models with this symmetry are used in the electron diffraction analysis.

The structural characteristics of crystalline germanium nanoparticles prepared by an evaporation method are discussed by transmission electron microscopy and electron energy-loss spectroscopy. It is also found that the diamond structure is stable when the particle diameter is as small as approximately 2 nm.

Highly periodic hexagonal honeycombs of platinum-germanium chalcogenide and platinum-tin selenide frameworks are prepared by linking corresponding [Ge4Q10] (super 4-) (Q=S,Se) and [Sn4 Se10] (super 4-) clusters with Pt (super 2+) ions. The use of square-planar Pt(super 2+) ions in a supramolecular assembly of adamantane [Ge4Q10] (super 4-) and [Sn4Selo] (super 4-) clusters leads to a new class of non-oxide mesostructured materials with exceptionally high hexagonal symmetry.

The reaction pathways of germylene (GeH2) and water, and the decomposition of germanol (H3GeOH) are studied using Guassian-2 (G2) molecular orbital theory. Ab initio calculations suggest that GeH2 react with H2O exothermically without a barrier to form a nonpolar H2GeOH2 complex, which isomerize to H3GeOH, through a 1,2-H shift with a barrier of 28.3 kcal per mol.

The electroluminescence of p-i-n diode structures in Ge dots consisting of coherent three-dimensional small (pyramids) and larger (dome) islands is studied. The study shows that the reduction of deposited area improves island uniformity and the combined analysis of island distribution and electroluminescence spectra has lead to the conclusion that domes in small diodes have smaller Si content or are less relaxed than domes in larger diodes.

The low-temperature magnetic structure of UPdGe, which crystallizes in the orthorhombic TiNiSi structure, is reported. It was found that at 5 K, the uranium moments were about 1.5 mu(sub B)/U atom and unlike in UPdGe, it was seen that the magnetic moments were perpendicular to the shortest interuranium distance d(sub U-U).

The physical loss mechanisms in boron doped poly-SiGe are studied. The microstructure of the SiGe layers is studied in order to identify interface defects and interstitial as the most important loss mechanisms.

Ab initio calculations based on density functional theory are used for studying energetic, structural, electronic and optical properties of Cr doped [Bi.sub.4][Ge.sub.3][O.sub.12] (BGO). The comparison with the experimental BGO:Cr absorption spectrum has shown that it has both [Cr.sup.3+] and [Cr.sup.4+] contributions, displaying the Cr simultaneous presencef at both substitution sites.

In situ x-ray diffraction is used for showing a pressure-induced crystallization of as-deposited amorphous [Ge.sub.2][Sb.sub.2][Te.sub.5] (a-GST) into a body-centered-cubic (bcc) solid solution and the back transformation from the bcc-GST to a-GST. The studies have shown that both routes have resulted in the same high-pressure amorphous state, which has described their crystallization into bcc-GST at similar pressures.

Several electronic band structure calculations are conducted to analyze the properties and orientations of the different biaxially strained Si, Ge and III-V semiconductors. The biaxial strain of the electron is shown to be highly dependent on the symmetry points.

Self-heating effects are examined in silicon-on-insulator (SOI), silicon-germanium-on-insulator (SGOI) and strained-silicon-directly-on-insulator (SSDOI) metal-oxide field-effect transistors (MOSFETs) by using Monte Carlo simulator self-consistently coupled with the solution of the heat diffusion equation. The dependence of the extent of self-heating on the buried-oxide thickness is analyzed, indicating that the parameter is important in designing SOI structures with better thermal management.

The hexagonal shapes of [Si.sub.0.13][Ge.sub.0.87] quantum dots (QDs) and rings on Si(110) have reflected the lattice symmetry of the top two Si layers on Si, which is different from that on Si(100). The Si cap layer is required for nanorings formation and the uncapped QDs are not transformed into rings even after a long time annealing.

The full potential augmented plane wave plus local orbital method using the local density approximation within the framework of density functional theory is used for examining structural, electronic and thermodynamic properties of [Sn.sub.x][Ge.sub.1-x] alloys for small Sn compositions. The studies have shown that the instability of SnGe alloys is dominated by a strong charge transfer between Sn and Ge, which has led to a positive chemical energy, where the instability is amplified by positive strain energy.

Heavily p-type doped Ge layers are prepared by 100 keV Ga implantation and subsequent flash lamp annealing and the structure of the doped layer and the Ga distribution are examined by Rutherford backscattering spectrometry. The Ga activation is correlated with the layer regrowth and incomplete epitaxial regrowth has led to lower activation.

The article explains the synthesis and structural characterization of the first two members of the homologous series [A.sub.2[n+m]][In.sub.2n+m][Ge.sub.2[n+m]] (n, m = 1, 2, ...[sigma]; A = Ca, Sr, Ba, Eu, or Yb), [([Eu.sub.1-x][Ca.sub.x]).sub.4][In.sub.3][Ge.sub.4] and [([Eu.sub.1-x][Ca.sub.x]).sub.3][In.sub.2][Ge.sub.3].

The growth kinetics of Ge crystals on silicon oxide by nanoscale seed induced lateral epitaxy is studied. Geometric phase analysis of high resolution transmission electron microscopy images and x-ray diffraction reciprocal space maps have shown that the Ge crystal stripes on Si[O.sub.2] layer are fully relaxed, homogeneous and fully coherent along their length.

Bulk-quantity single crystalline Ge dioxide nanowires (GeONWs) are prepared by using facile and simple hydrothermal deposition process using Ge[O.sub.2] powder. Room temperature photoluminescence measurement has indicated that the GeONWs have intense violet light emission and blue light emission and they have followed the vapor-solid growth mechanism.

The well known Fisher model is utilized to measure and compare the Ge diffusivity in micro- and nanocrystalline Si layers. The diffusivities in nanograins and nanograin boundaries are found to be one order of magnitude higher when compared to micrograins and micrograin boundaries while the activation energy in nano- as well as micrograin boundaries are same.

A 658-nm laser beam is used to evaluate the speed of amorphous-to-crystalline phase transformation in [Ge.sub.2][Sb.sub.2][Te.sub.5] and [Ag.sub.0.1]][([Ge.sub.2][Sb.sub.2][Te.sub.5]).sub.0.9] thin films, on a nanosecond time scale. The experimental results revealed that the crystallization speed of the [Ge.sub.2][Sb.sub.2][Te.sub.5] films could be largely improved by addition of Ag, which could lead to a low programming current in electronic operation.