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Barrett, Christopher A.
Preferred name
Barrett, Christopher A.
Official Name
Barrett, Christopher A.
Research Output
Now showing 1 - 4 of 4
- PublicationSpontaneous room temperature elongation of CdS and Ag2S nanorods via oriented attachment(ACS Publications, 2009-08-06)
; ; ; ; ; ; ; Spontaneous elongation from nanorod to nanowire in the presence of an amine is reported for nanocrystals of cadmium sulfide and silver sulfide (cation exchanged from CdS). Elongation occurs instantaneously where the final aspect ratio is a controllable multiple of the original nanorod length. Transmission electron microscopy (TEM) analysis reveals the influential factors on the attachment processare the concentration of amine, duration and temperature of the reaction. The elongated nanorods are further characterized by X-ray diffraction (XRD), photoluminescence (PL), ultraviolet-visible spectroscopy(UV-vis) and X-ray photoelectron spectroscopy (XPS). A mechanism of oriented attachment is evidenced by the doubling in length of asymmetrically gold tipped CdS nanorods with the corresponding absence of elongation in symmetrically tipped nanorods.826Scopus© Citations 86 - PublicationMetal surface nucleated supercritical fluid–solid–solid growth of Si and Ge/SiOx core–shell nanowires(RSC publications, 2010-01)
; ; ; ; ; ; High yields of single-crystalline silicon nanowires and germanium/silicon oxide core-shell nanostructures were synthesized using a supercritical fluid-solid-solid growth mechanism. The formation of the one-dimensional nanostructures was investigated on stainless steel and titanium reactor cell walls. The nanowire growth is diffusion controlled with no catalyst particles being observed at the tip of the nanowires, which is contrary to the characteristic feature of a one-dimensional growth based on the vapor-liquid-solid mechanism. The diameter and length of the nanowires were in the ranges of 30-60 nm and 1-10 µm, respectively, as found by high-resolution electron microscopy. The nanowires were characterized by transmission electron microscopy (TEM), energy-dispersive X-ray spectroscopy (EDX) and scanning electron microscopy (SEM).597Scopus© Citations 21 - PublicationA facile spin-cast route for cation exchange of multilayer perpendicularly-aligned nanorod assemblies(RSC publications, 2011-10-07)
; ; ; ; ; ; ; A facile spin cast route was developed to convert perpendicularly aligned nanorod assemblies of cadmium chalcogenides into their silver and copper analogues. The assemblies are rapidly cation exchanged without affecting either the individual rod dimensions or collective superlattice order extending over several multilayers.Scopus© Citations 36 740 - PublicationSize controlled gold tip growth onto II–VI nanorods(RSC publications, 2010-09-28)
; ; ; ; Gold tip size and multiplicity is controlled in hybrid gold-semiconductor nanorods (CdS-Au, CdSe-Au and CdTe-Au) in fast reaction times of less than 2 minutes by optimising precursor type, concentration, and temperature. Controllable gold tips up to as large as 40 nm on a rod diameter of 7 nm are reported with the tip size shown to be directly related to the redox potentials of the dangling atoms on the nanorod and the gold chloride precursors (mono or trivalent). The preference for symmetric (both ends) over asymmetric (single end) is achieved by simply elevating the reaction temperature to 80ºC without changing the reaction time. TEM and XRD analysis were preformed to verify both the gold nanoparticle size and crystallinity of the hybrid nanostructures. Increased quenching of nanorod emission is observed as the size of the gold tip increases suggesting optimisation of charge transfer between the semiconductor and the metal.Scopus© Citations 36 735