Electrochemical synthesis of ultrafast and gram-scale surfactant-free tellurium nanowires by gas–solid transformation and their applications as supercapacitor electrodes for p-doping of graphene transistors

We herein report a gas-solid transformation mechanism for the surfactant-free synthesis of Te NWs at room temperature by electrolysis of bulk Bi2Te3 using H2Te gas. Te NWs, with an average diameter below 20 nm, grow along the [001] direction due to the unique spiral chains in the crystal structure and show an enhanced Raman scattering effect, a broad absorption band over the range of 350-750 nm and an emission band over the range of 400-700 nm in the photoluminescence spectrum. In terms of device applications, we demonstrate how Te NWs can be directly applied as a p-type dopant source in order to shift the Dirac point in ambipolar field effect graphene transistors. Finally, the favorable capacitive properties of Te NWs are established as supercapacitor electrodes with negligible internal resistance and excellent electrochemical reversibility and a specific capacitance of 24 F g-1

Anomalous electrical performance of nanoscaled interfacial oxides for bonded n-GaAs wafers

Electrical performance was found to be closely related to the variation of nanosized interface morphology in previous studies. This work investigated in detail the microstructural development of in- and anti-phase bonded interfaces for n-type (100) GaAs wafers treated at 500, 600, 700 and 850 degrees C. The interfacial energy of anti-phase bonding is higher than that of in-phase bonding based on the first-principles calculations. The higher interface energy tends to stabilize the interfacial oxide layer. The continuous interfacial oxide layer observed below 700 degrees C can deteriorate the electrical property due to its insulating property. However, the existence of nanoscaled oxide at anti-phase bonded interfaces can improve the electrical conductivity at 700 degrees C. This is due to the suppression of the evaporation of As atom by the interfacial nanoscaled oxides based on the analysis of autocorrelation function and energy dispersive x-ray spectroscopy. (c) 2006 American Institute of Physics

Ultra-sharp α-Fe2O3 nanoflakes: Growth mechanism and field-emission

10.1007/s00339-007-4180-9Applied Physics A: Materials Science and Processing891115-119APAM