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We present the HEtero-Layer Lift-Off (HELLO) technique to obtain ultra thin body (UTB) Ge on insulator (GeOI) substrates. The transferred ultra thin Ge layers are characterized by the Raman spectroscopy measurements down to the thickness of ∼1 nm, observing a strong Raman intensity enhancement for high quality GeOI structure in ultra thin regime due to quantum size effect. This advanced Ge layer transfer technique enabled us to demonstrate UTB-GeOI nMOSFETs with the body thickness of only 4 nm.

Hydrogen-saturated silicon clusters of Si6H12 and Si8H18 deposited on Si(111)-(7×7) surfaces were intentionally assembled as islands 5–50 nm in diameter using scanning tunneling microscopy. Assembling occurs for both clusters when the tip–substrate bias voltage exceeds 3 V, irrespective of voltage polarity. Observed kinetics indicate that the mechanism is directional diffusion caused mainly by interaction between the electric field and the field-induced dipole moment of clusters. We demonstrate that the assembling process is applicable to the formation of artificial cluster nanostructures.

We evaluated the potential of polycrystalline (poly-) GeSn as channel material for the fabrication of thin film transistors (TFTs) at a low thermal budget (

We demonstrate Fermi-level depinning in metal/Ge junctions and a significant reduction of specific contact resistivity of n-Ge by inserting an ultra-thin semiconducting Si-rich W silicide film (WSin, n = 12–14) composed of W-encapsulating Si clusters. Dependence of the specific contact resistivity on the electron Schottky barrier height followed the ideal exponential relation for various contact metal species. This result indicates that the insertion of the WSin film provides a negligible contribution to contact resistivity because its tunneling resistance is very low owing to the low offset of the conduction band edge of Ge.

We demonstrate electrical junction characteristics of epitaxially grown W silicide (WSin, n = 8–10) films composed of W-encapsulating Si clusters on Si substrates. The current-voltage and capacitance-voltage characteristics revealed that the WSin/n-Si junction is ohmic, while the WSin/p-Si junction is rectifying with good interface quality and a barrier height of 0.8 eV. The WSin film is an n-type high-carrier-concentration narrow-gap semiconductor with the Fermi level close to the conduction band edge of Si, and it forms a low-barrier heterojunction to n-Si.

application/pdf, We have developed a robust method for fabricating Si nanoregions in silica glass using femtosecond laser processing. We attained a vivid formation of silicon-rich nanoregions site-selectively generated in SiO2 by irradiation of femtosecond laser pulses to the interface of a SiO2 substrate and deposited aluminum (Al) thin film, where the Al element acts as a gettering site for O atoms. Growth of high-density Si nanocrystals and amorphous Si was observed by transmission electron microscopy in the region that was multiply irradiated with the femtosecond laser. Furthermore, local annealing with a cw laser enhances the Si nanocrystal growth, which was determined by micro-Raman measurements.

Using scanning tunneling microscopy, the authors show that uniform-size Mo-encapsulating Si clusters, MoSin, were synthesized on Si (111)-7×7 surfaces by the reaction between SiH4 and Mo atoms deposited on the surface followed by thermal annealing at 600°C. Comparing observed images with ab initio structure calculations indicates that n=6. According to scanning tunneling spectroscopy measurements, the MoSin cluster has a semiconducting energy gap of approximately 0.3eV, indicating that the metallic electronic state of the 7×7 surface can be locally modified by formation of the MoSin cluster.

application/pdf, Phosphorus (P) doping was performed during the synthesis of silicon nanowires (SiNWs) by laser ablation. At least three types of signals were observed by electron spin resonance (ESR) at 4.2 K. Phosphorus doping into substitutional sites of crystalline Si in SiNWs was demonstrated by the detection of an ESR signal with a g value of 1.998, which corresponds to conduction electrons in crystalline Si, and by an energy-dispersive x-ray spectroscopy spectrum of the P Kalpha line. The ESR results also revealed the presence of defects. These defects were partially passivated by hydrogen and oxygen atoms.