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Orientation-controlled Si films on transparent insulating substrates are strongly desired to achieve high-efficiency thin-film solar cells. We have developed the interfacial-oxide layer modulated Al-induced low temperature (<450 °C) crystallization technique, which enables dominantly (001) or (111)-oriented Si films with large grains (20–100 μm). These results are qualitatively explained on the basis of a model considering the phase transition of the interfacial Al oxide layers. This process provides the orientation-controlled Si templates on insulating substrates, which enables successive high quality epitaxial growth necessary for advanced Si thin-film solar cells.

Impact of atomic layer deposition temperature on HfO2/InGaAs metal-oxide-semiconductor interface properties J. Appl. Phys. 112, 084103 (2012) Method for investigating threshold field of charge injection at electrode/dielectric interfaces by space charge observation Appl. Phys. Lett. 101, 172902 (2012) An accurate characterization of interface-state by deep-level transient spectroscopy for Ge metal-insulatorsemiconductor capacitors with SiO2/GeO2 bilayer passivation J. Appl. Phys. 112, 083707 (2012) Electron transport properties of carbon nanotube-graphene contacts Appl. Phys. Lett. 101, 153501 (2012) Response to "Comment on 'Broadening of metal-oxide-semiconductor admittance characteristics: Measurement, sources, and its effects on interface state density analyses'" [J. Appl. Phys. 112, 076101 (2012) (111)-oriented Ge thin films on insulators are essential for advanced electronics and photovoltaic applications. We investigate Al-induced crystallization of amorphous-Ge films (50-nm thickness) on insulators focusing on the annealing temperature and the diffusion controlling process between Ge and Al. The (111)-orientation fraction of the grown Ge layer reaches as high as 99% by combining the low-temperature annealing (325 C) and the native-oxidized Al (AlO x ) diffusioncontrol layer. Moreover, the transmission electron microscopy reveals the absence of defects on the Ge surface. This (111)-oriented Ge on insulators promises to be the high-quality epitaxial template for various functional materials to achieve next-generation devices. V C 2012 American Institute of Physics. [http://dx

To develop silicon-based spintronic devices, we have explored high-quality ferromagnetic Fe3Si/silicon (Si) structures. Using low-temperature molecular beam epitaxy at 130 • C, we realize epitaxial growth of ferromagnetic Fe3Si layers on Si (111) with keeping an abrupt interface, and the grown Fe3Si layer has the ordered DO3 phase. Measurements of magnetic and electrical properties for the Fe3Si/Si(111) yield a magnetic moment of ∼ 3.16 µB/f.u. at room temperature and a rectifying Schottky-diode behavior with the ideality factor of ∼ 1.08, respectively. PACS numbers:Semiconductor spintronic devices such as spin-field effect transistors (spin FET) are one of the possible candidates to substitute for existing silicon-based complementary metal-oxide-semiconductor devices. [1,2,3,4] To realize operations of the spin FET, an electrical spin injection from ferromagnets into semiconductors is an essential technology. For III-V semiconductor devices, several groups have demonstrated highly efficient spin injection and detection using an epitaxial Fe thin film and tailored Schottky tunnel barriers so far. [5,6,7] From these facts, it is necessary for semiconductor spintronics to develop crystal growth techniques of ferromagnets on semiconductors with keeping high-quality interfaces. In particular, it will become key to build epitaxial growth of ferromagnets on silicon (Si) from the viewpoint of application to existing silicon large-scale integrated circuit (LSI) technologies. [8] Moreover, for spintronics, Si has been regarded as an ideal material because of a long spin relaxation time due to weak spin-orbit interaction, weak hyperfine interaction and lattice inversion symmetry, which will give rise to a long spin diffusion length in the devices. Recently, spin transport in Si conduction channels was experimentally demonstrated although their operations were limited at low temperatures. [9,10,11] This means that the spin degree of freedom can be introduced into Si-based electronic devices.To date, ferromagnetic MnAs thin films have been grown epitaxially on Si (001), [12] but electrical spin injection from MnAs into Si across a Schottky tunnel barrier has never been demonstrated unfortunately. Also, the Curie temperature of MnAs is ∼ 315 K, [13] which may be relatively low for an operation temperature of future LSIs. Thus, possibilities of other high-Curie temperature materials compatible with Si should be explored. Here we select a ferromagnetic Heusler alloy Fe 3 Si thin film, which has a high Curie temperature above 800 K, a relatively high spin polarization of ∼ 45 % and a small coercive field of ∼ 7.5 Oe. [14] In this letter, we achieve highly

The generation, manipulation and detection of a pure spin current (i.e., the flow of spin angular momentum without a charge current) are prospective approaches for realizing next-generation spintronic devices with ultra-low electric power consumption. Conventional ferromagnetic electrodes such as Co and NiFe have been utilized as spin injectors to generate pure spin currents in nonmagnetic channels. However, the generation efficiency of pure spin currents is extremely low at room temperature, giving rise to a serious obstacle for device applications. Here we demonstrate the generation of giant pure spin currents at room temperature in lateral spin valve devices with a highly ordered Heusler-compound Co 2 FeSi (CFS) spin injector. The generation efficiency of pure spin currents from the CFS spin injectors is 10 times greater than that of the NiFe injectors, indicating that Heusler compound spin injectors with high spin polarization enable us to materialize a high-performance lateral spin device. The present study is a technological jump in spintronics, and indicates the great potential of ferromagnetic Heusler compounds with half metallicity for generating pure spin currents.