420 research outputs found
Development of a Compact Neutron Source based on Field Ionization Processes
The authors report on the use of carbon nanofiber nanoemitters to ionize
deuterium atoms for the generation of neutrons in a deuterium-deuterium
reaction in a preloaded target. Acceleration voltages in the range of 50-80 kV
are used. Field emission of electrons is investigated to characterize the
emitters. The experimental setup and sample preparation are described and first
data of neutron production are presented. Ongoing experiments to increase
neutron production yields by optimizing the field emitter geometry and surface
conditions are discussed.Comment: 4 pages, 5 figures; IVNC 201
Self-Aligned Ballistic Molecular Transistors and Electrically Parallel Nanotube Arrays
Carbon nanotube field-effect transistors with structures and properties near
the scaling limit with short (down to 50 nm) channels, self aligned geometries,
palladium electrodes with low contact resistance and high-k dielectric gate
insulators are realized. Electrical transport in these miniature transistors is
near ballistic up to high biases at both room and low temperatures. Atomic
layer deposited (ALD) high-k films interact with nanotube sidewalls via van der
Waals interactions without causing weak localization at 4 K. New fundamental
understanding of ballistic transport, optical phonon scattering and potential
interfacial scattering mechanisms in nanotubes are obtained.Comment: Nano Letters, in pres
19.2% Efficient InP Heterojunction Solar Cell with Electron-Selective TiO2 Contact.
We demonstrate an InP heterojunction solar cell employing an ultrathin layer (∼10 nm) of amorphous TiO2 deposited at 120 °C by atomic layer deposition as the transparent electron-selective contact. The TiO2 film selectively extracts minority electrons from the conduction band of p-type InP while blocking the majority holes due to the large valence band offset, enabling a high maximum open-circuit voltage of 785 mV. A hydrogen plasma treatment of the InP surface drastically improves the long-wavelength response of the device, resulting in a high short-circuit current density of 30.5 mA/cm2 and a high power conversion efficiency of 19.2%
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