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

The layer exchange technique enables high-quality multilayer graphene (MLG) on arbitrary substrates, which is a key to combining advanced electronic devices with carbon materials. We synthesize uniform MLG layers of various thicknesses, t, ranging from 5 nm to 200 nm using Ni-induced layer exchange at 800 °C. Raman and transmission electron microscopy studies show the crystal quality of MLG is relatively low for t ≤ 20 nm and dramatically improves for t ≥ 50 nm when we prepare a diffusion controlling Al2O3 interlayer between the C and Ni layers. Hall effect measurements reveal the carrier mobility for t = 50 nm is 550 cm2/Vs, which is the highest Hall mobility in MLG directly formed on an insulator. The electrical conductivity (2700 S/cm) also exceeds a highly oriented pyrolytic graphite synthesized at 3000 °C or higher. Synthesis technology of MLG with a wide range of thicknesses will enable exploration of extensive device applications of carbon materials.

Multilayer graphene (MLG) growth on arbitrary substrates is desired for incorporating carbon wiring and heat spreaders into electronic devices. We investigated the metal-induced layer exchange growth of a sputtered amorphous C layer using Ni as a catalyst. A MLG layer uniformly formed on a SiO2 substrate at 600 °C by layer exchange between the C and Ni layers. Raman spectroscopy and electron microscopy showed that the resulting MLG layer was highly oriented and contained relatively few defects. The present investigation will pave the way for advanced electronic devices integrated with carbon materials.

Polycrystalline GeSn thin films are fabricated on insulating substrates at low temperatures by using Sn-induced crystallization of amorphous Ge (a-Ge). The Sn layer stacked on the a-Ge layer (100-nm thickness each) had two roles: lowering the crystallization temperature of a-Ge and composing GeSn. Slow annealing at an extremely low temperature of 70 °C allowed for a large-grained (350 nm) GeSn layer with a lattice constant of 0.590 nm, corresponding to a Sn composition exceeding 25%. The present investigation paves the way for advanced electronic optical devices integrated on a flexible plastic substrate as well as on a Si platform.

The Ni-induced layer-exchange growth of amorphous carbon is a unique method used to fabricate uniform multilayer graphene (MLG) directly on an insulator. To improve the crystal quality of MLG, we prepare AlOx or SiO2 interlayers between amorphous C and Ni layers, which control the extent of diffusion of C atoms into the Ni layer. The growth morphology and Raman spectra observed from MLG formed by layer exchange strongly depend on the material type and thickness of the interlayers; a 1-nm-thick AlOx interlayer is found to be ideal for use in experiments. Transmission electron microscopy and electron energy-loss spectra reveal that the crystal quality of the resulting MLG is much higher than that of a sample without an interlayer. The grain size reaches a few μm, leading to an electrical conductivity of 1290 S/cm. The grain size and the electrical conductivity are the highest among MLG synthesized using a solid-phase reaction including metal-induced crystallization. The direct synthesis of uniform, high-quality MLG on arbitrary substrates will pave the way for advanced electronic devices integrated with carbon materials.