Ward P Beyermann

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A high-temperature solution-phase hydrolysis approach has been developed for the synthesis of colloidal magnetite nanocrystals with well-controlled size and size distribution, high crystallinity, and high water solubility. The synthesis was accomplished by the hydrolysis and reduction of iron(III) cations in diethylene glycol with a rapidly injected(More)
We use terahertz time domain spectroscopy (THz-TDS) to determine the complex frequency-dependent dielectric response of all four nucleotides at different dilute concentrations. In addition, the suspension model's ability to extract the dielectric response of just the nucleotide with the hydration shell epsilon(b) excluding the dielectric information(More)
In searching appropriate candidates of magnetic semiconductors compatible with mainstream Si technology for future spintronic devices, extensive attention has been focused on Mn-doped Ge magnetic semiconductors. Up to now, lack of reliable methods to obtain high-quality MnGe nanostructures with a desired shape and a good controllability has been a barrier(More)
Phosphorus-doped p-type ZnO films were grown on r-plane sapphire substrates using molecular-beam epitaxy with a solid-source GaP effusion cell. X-ray diffraction spectra and reflection high-energy electron diffraction patterns indicate that high-quality single crystalline ͑112 ¯ 0͒ ZnO films were obtained. Hall and resistivity measurements show that the(More)
Reproducible Sb-doped p-type ZnO films were grown on n-Si ͑100͒ by electron-cyclotron-resonance-assisted molecular-beam epitaxy. The existence of Sb in ZnO:Sb films was confirmed by low-temperature photoluminescence measurements. An acceptor-bound exciton ͑A ° X͒ emission was observed at 3.358 eV at 8 K. The acceptor energy level of the Sb dopant is(More)
Solvothermal reaction of a mixture of Sn, Mn, and Te at 200 degrees C using teta as the solvent yields a novel inorganic-organic hybrid solid [Mn(teta)(en)].[Mn(teta)][Mn(SnTe4)2.Mn(teta)] (teta=triethylenetetramine and en=ethylenediamine; 1), which has a homochiral single-stranded helical structure. The material is a semiconductor with a band gap of 0.88(More)
Nanoscale objects that combine high luminescence output with a magnetic response may be useful for probing local environments or manipulating objects on small scales. Ideally, these two properties would not interfere with each other. In this paper, we show that a fluorescent polymer host material can be doped with high concentrations of 20-30 nm diameter(More)
Facile, cost-effective, and manufacturable techniques to create single-nanowire based devices with good electrical interconnects is demonstrated by combining template directed electrodeposition, magnetic assembly, and a post-annealing in a reducing environment. Nickel nanowires with a diameter of approximately 30 nm were electrodeposited from low-stress(More)
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