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Ni- or Au-induced crystallization and the lateral crystallization of planar amorphous germanium ([alpha]-Ge) on silicon dioxide at 360 [degree] centigrade without the deleterious effects of thermally induced self-nucleation is examined. This method is used for forming the channel region of the MOS devices in upper layers of the three-dimensional integrated circuits at low temperatures.

The isothermal variation of the entropy ([DELTA][S.sub.T]) for the compound [Gd.sub.5][Ge.sub.4] is studied at different applied hydrostatic pressures. Different protocols are used to obtain [DELTA][S.sub.T] at zero applied pressure and the results have shown that [DELTA][S.sub.T] has depended on the initial and final states of [Gd.sub.5][Ge.sub.4] compound.

The quality of films deposited in a radio frequency powered plasma enhanced chemical vapor deposition unit is examined. The studies have shown that a balance between ion bombardment and nanocrystalline incorporation in the film is controlled by varying the radiofrequency power duty cycle to provide device grade films.

The surfactant-directed assembly of mesoporous metal/germanium-based semiconducting materials from coupling of anionic [([Ge.sub.9]).sup.4-] clusters with various linking metal ions is described. The photoemission intensity in the mesoporous intermetallic germanium-based frameworks is selectively suppressed by adsorbing electron-acceptor species such as tetracyanoethylene molecules, but has remained unchanged when exposed to electron-donor species such as tetrathiafulvalene molecules.

The (3+1)D superspace techniques were used to solve the structure of YCo0.88Ga3Ge, which exhibit a locked -in charge density wave. The results showed that the wave is located in the square net of gallium atoms present in the structure and is coupled to a site occupancy wave of Co atoms above and below the square net.

A practical reductive cross-aldol reaction of [alpha]-bromoaldehydes with various aldehydes is developed by using Ge(II)[Cl.sub.2] to produce aldehyde germanium(IV) aldolates, which are directly transformed to various multifunctionalized compounds. The studies have disclosed the generation of stable germanium aldolates, which is due to the low Lewis acidity of the germanium(IV).

The synthesis of high-density, vertically oriented Ge nanowires with precise control over the size and orientation via biotemplating of very small sized Au nanoparticle catalysts are described. The biotemplating approach is applicable for a variety of nanowires and substrate materials.

The synthesis of new types of cyclopentadienides ([Cp.sup.-]) analogues containing divalent group 14 elements, leading to electron-rich transition-metal complexes with very high reduction potential, is described. The reduction of the sterically encumbered but coordinatively flexible [beta]-diketiminato Ge(II) chloride with potassium in THF at ambient temperature has furnished the first cyclogermylidenide derivative in the form of its potassium salt.

The diffusion and activation of n-type impurities P and As) implanted into p-type Ge(100) substrates are examined under various dose and annealing conditions. The profiles of P in Ge substrates with and without damage generated by Ge ion implantation are compared and it is clarified that the damage that might compensate the activated n-type dopants does not have any relationship with the activation of P in Ge.

The germanium (Ge) nanocrystals (NCs) are prepared by using the rapid-thermal annealing and are embedded into a three-layer (Si[O.sub.2]/NCs-Ge/Si[O.sub.2]) capacitor structure. The characteristic time constant has become smaller, which is attributed to the reduction of trap density and has agreed that the interface traps are dominant and has a small characteristic time constant.

The magnetism of amorphous [Ge.sub.1-x][Mn.sub.x] films with various high Mn concentrations prepared of liquid-nitrogen (L[N.sub.2])-cooled glass substrates by ultrahigh vacuum (UHV) thermal coevaporation. All the [Ge.sub.1-x][Mn.sub.x] magnetic semiconductor films have shown semiconducting transport behavior and anomalous Hall effects below the Curie temperature, indicating carrier-mediated ferromagnetism.

Type-I clathrates [Yb.sub.x][Ba.sub.8-x][Ga.sub.16][Ge.sub.30] filled by ytterbium and barium are synthesized and the structure and thermoelectric properties of double-atoms-filled clathrate compounds are examined. All specimens have shown n-type conduction and the room temperature carrier concentration has increased with the increasing Yb content, where the electrical conductivity of the compound has increased at first and then has decreased with the increasing Yb content.

Thermoelectric properties of Al-substituted Ge clathrate compounds [Ba.sub.8][Al.sub.x][Ge.sub.46-x] are examined. The studies have shown that the thermoelectric properties can be improved by controlling the carrier concentration.

The mechanical and thermal properties of single crystals of the type-I clathrate compounds [Ba.sub.8][Ga.sub.16][Ge.sub.30] and [Sr.sub.8][Ga.sub.16][Ge.sub.30] are examined by measuring the elastic constants, coefficients of thermal expansion (CTE) and plastic deformation behavior in compression. The thermal stresses developed due to CTE mismatch between the clathrate compounds and electrode is small when Ni is used as the electrode.

Experimental evidence is provided for intense electronic excitation induced athermal crystallization of amorphous germanium (a-Ge) grown on crystalline germanium substrate. The results are described by using local transient melting due to a high rate of energy deposition by the silver ions and its subsequent cooling.

The ability of molecular-dynamics simulation to analyze the thermal transport in Si-Ge alloys is examined. The results have major implications for using classical molecular-dynamics simulations for predicting properties of alloy materials near and below the Debye temperature.

The structural and optical properties of nanocrystalline Ge films prepared by isotropic chemical etching on single-crystalline Ge substrates are examined by using transmission electron microscopy and infrared spectroscopy. The studies have shown that despite the substrate resistivity and orientation, 3-4 nm and diamond-structured Ge nanocrystals (NCs) with disordered surfaces are obtained and a stable photoluminescence is seen in the red/near-infrared region at room temperature.

A study was conducted to calculate the electronic structure near the [Gamma] point and interband optical matrix elements of strained Sn and SnGe quantum dots in a Si or Ge matrix. The self-assembled Sn/Si dots of sizes between 4 and 12 nm were found to have indirect interband transitions from 0.8 t 0.4 eV and direct interband transitions from 2.5 to 2.0 eV.

A combination of capacitance-voltage (C-V), deep-level transient spectroscopy (DLTS), and electron-beam induced current (EBIC) techniques were used to study the Si/[Si.sub.1-x][Ge.sub.x]/Si heterostructures consisting of relaxed SiGe layers of graded and constant composition with a strained-Si layer on top. The data obtained showed that electrically active defects located close to the strained-Si/SiGe interface are attributed to partial relaxation of the strained-Si layer.

The x-ray photoelectron spectroscopy technique is employed to study the synthesis and properties of the clean and oxidized [alpha]-GeTe(111) surfaces. The surfaces are shown to exhibit different surface structures in the different ranges of oxidation of the system.

The mechanisms involved in the formation of the self-organized structures in thin films of silicon-germanium are studied. The results prove that an increase in the solidification velocity of the system can be easily employed to turn off the self-organization phenomenon of the structures.

Several high-resolution Raman measurements are conducted to determine the photon strain shift coefficients found in the [Si.sub.1-x][Ge.sub.x] alloys. The results demonstrate that the discussed strain shift coefficients are completely independent of the composition of the heterostructures.

Several studies are conducted to explain the synthesis and structural characteristics of GeTe-rich GeTe-[Sb.sub.2][Te.sub.3] pseudobinary metastable crystals. An increase in the temperature is shown to lead to a change in the structure of the crystals from a slightly distorted NaCl-type structure to a regular type.

Several theoretical quantum chemistry studies are conducted to explain the cation structures and vibrational frequencies of the fluorinated and chlorinated germanes and their radicals. The most stable cationic structures are found to be extremely different from their neutral counterparts.

A combined structure and stoichiometry study is presented on the growth behavior of single crystalline Ge(111) layers on Pr[O.sub.2](111)/Si(111) heterostructures. A Volmer-Weber growth mode is seen that has resulted after island coalescence in the formation of atomically smooth, single crystalline Ge(111) layers.

The scanning tunneling microscopy (STM) and high-resolution core-level photoemission spectroscopy (HRCLPES) are used for elucidating the adsorption and electronic structures of Al[Cl.sub.3] on Ge(100). The studies have shown that Al[Cl.sub.3] molecules adsorb on the Ge(100) surface via a cycloaddition-like reaction and form di-[sigma] bonds in which the Al[Cl.sub.3] molecules have interacted with the surface dimers of Ge(100).

A spectroscopic scanning capacitance microscopy (SCM) was used to examine the trapping of electrons and holes in Ge nanodots fabricated on a highly doped silicon substrate. The hole traps sites were found to be possibly located at or closer to the surface of the Ge nanodots as compared to electron traps which might be located deeper within the Ge nanorods.

A comprehensive study which provide insight into association between the magnetic properties and structural properties of [Mn.sup.+]-implanted [Si.sub.1-x][Ge.sub.x] films as a function of Ge content (x=0-0.5] is presented. The results revealed that the magnetic, electrical, and microstructural properties, as well as the local structural environment are affected by annealing and Ge alloying in [Mn.sup.+]-implanted [Si.sub.1-x][Ge.sub.x].

The epitaxial growth of the IV-VI diluted magnetic semiconductor [Ge.sub.1-x][Mn.sub.x]Te by molecular beam epitaxy is reported. The results from the hard x-ray photoemission measurements confirmed the existence of the strong p-d exchange which gives rise to ferromagnetic order.

A wide range of temperature and oxygen partial pressures were employed to explore the growth of both Si[O.sub.2] and mixed oxides of Si and Ge. The results confirmed the dominant effect of the thermodynamic driving force for Si[O.sub.2] growth and the significant role of Ge pileup at the growing interface influencing the growth rate and interfacial sub-bonding.

The slow insertion of Si[Me.sub.2] into dimethylgermane as compared to dimethylsilylene is investigated by kinetic studies and quantum chemical calculations. The results show that the insertion into Si-H and Ge-H occurs through intermediate H-bonded complexes, and the complexes of germane substrates have a higher barrier for rearrangement to the final product than the silane substrates.

Irradiation of germanium (Ge) isotope heterostructures with 2.5 MeV protons are performed at elevated temperature. Annealing under proton irradiation have caused as inhomogeneous intermixing and two different characteristics in the intermixing are ascribed to radiation enhanced self-diffusion and the formation of microscopic voids.

Quantum chemical calculations are used for examining the structure and properties of small neutral and cationic Cr[Ge.sub.n.sup.0,+) (n = 1-5) clusters. Electron localization function (ELF) analyses have shown that the chemical bonding in chromium-doped germanium clusters have differed from that of their pure or Li-doped counterparts and have allowed the origin of the inherent high-spin ground state to be described.

The synthesis of a germanium-centered dication is described. The combination of a metal-centered lone pair of electrons and a large positive charge has made this complex unique in group 14 chemistry and a key contribution to known p-block-centered dications.

Hydrogenated nonstoichiometric germanium materials are produced by x-ray activated-chemical vapor deposition from germane and the reaction pattern leading to the solid products are examined. The Raman results and optical parameters have shown that the structural order, both short-range and intermediate-range, has decreased with increasing irradiation time.

High resolution transmission electron microscopy is used for analyzing the microstructure of epitaxially grown self-assembled Ge islands on patterned Si[O.sub.2]/Si substrates. The results have highlighted the microstructural issues and growth behavior of quantum dots on patterned substrates.

A study was conducted to examine the nanowire growth at the deep subeutectic temperatures that are often used for germanium nanowire growth with Au catalyst nanoparticles. The interdependence of the pressure and temperature required for good quality germanium nanowire growth could be applied in other types of nanowire growth.

The potential of the memory structure with Ge nanocrystals embedded in lanthanide-based [Lu.sub.2][O.sub.3] high-k dielectrics for low voltage NVM applications is demonstrated.

A study was conducted to determine the elastic properties of the Ge[Sb.sub.2][Te.sub.4] alloy in three phases, namely, amorphous, metastable cubic crystal, and as a hexagonal stable crystal. The measured elastic moduli from the chalcogenide alloy provided a benchmark for computational predictions of film properties.

A quantum chemical model is used to study the photoexcitation, photoluminescence and other optical properties of the oxygen vacancies (OVs) in germanium oxides. The results show that the double OV is most suitable for generating bright blue photoluminescence.

The synthesis and characterization of the Germanium phthalocyanine, GePc, and the reduced complexes like SiPc[(pyridine).sub.2] and GePc[(pyridine).sub.2] are described. The analysis reveals that these complexes contain various antiaromatic [pi]-electron circuits.

The synthesis and characterization of two unusual germanium(II) calixarene complexes via the protonolysis reaction between the bulky germanium(II) amide Ge[[N[(Si[Me.sub.3]).sub.2]].sub.2] and calix[4]arene or calix[8]arene which contain two germanium atoms arranged in central [Ge.sub.2][O.sub.2] rhombus is reported.

The influence of the number and the thickness of the silicon spacer layer on the optical and structural properties of single and multilayers of self-assembled Ge/Si(001) islands is examined. The results have shown the optimal growth sequence that needs to obtain homogeneous and ordered multilayers.

The hydrothermal synthesis and structural characterization of the first bimetallic complexes containing the divalent tris(oxalate-O,O')germinate anion or the neutral bis(oxalate-O,O-)germanium fragment with transition-metal (M) cationic complexes of 1,10'-phenanthroline (phen) are presented. The results have shown that the large chemical species composing each complex structure are closely packed in the solid state mediated by subnetworks of intermolecular interactions.

The studies related to the thermoelectric properties of a class of compounds of composition [R.sub.3][Ru.sub.4][Ge.sub.13] (R = Y, Dy, Ho, and Lu) are presented. Each of the compounds displays a semiconductor like rise in electrical resistivity with decreasing temperature.

Variable-energy positron annihilation spectroscopy (VEPAS) is used for observing fluorine-vacancy (FV) complexes in the [Si.sub.0.94][Ge.sub.0.06] layer in a Si-SiGe-Si structure. The concentration of [F.sub.4n][V.sub.n] complexes is critically dependent on annealing temperature, decreasing significantly after annealing at 1000 [degree] C.

The effects of thermal annealing on the structures of Ge-Sb-Te (GST) nanoparticles synthesized by pulsed laser ablation deposition are examined. The results have shown that the nanoparticles are crystalline, which also consists of a mixture of face centered cubic (fcc) and hexagonal [Ge.sub.2][Sb.sub.2][Te.sub.5] nanoparticles.

First-principles calculations are used for investigating structural, electronic and optical properties of [alpha], [beta] and [gamma] phases of germanium nitride ([Ge.sub.3][N.sub.4]). The results have shown that the band gap and static dielectric constants of [Ge.sub.3][N.sub.4], as well as [Si.sub.3][N.sub.4], might satisfy the requirements of gate dielectrics for Ge-based field effect transistors.

The electronic structure of mono-, di-, and tri-lithiated triatomic germanium were studied with the help of quantum chemical calculations. The electron affinities of calculated for triatomic germanium show that only monoanion is stable to form lithiated germanium.

The structural, magnetic and electronic properties of [Mn.sub.x][Ge.sub.1-x] single crystals, which are prepared by the Bridgman's crystal growth technique, are studied. The formation of ferromagnetic intermetallic compounds is identified as the most possible origin of ferromagnetism in both Mn-rich and Mn-poor regions of the [Mn.sub.x][Ge.sub.1-x] samples.