Growth and luminescence properties of micro- and nanoneedles in sintered CdSe

Abstract

Sintering CdSe powder under argon flow at temperatures in the range 800–900 °C produces the formation of needles on the sample surface. Bundles of parallel needles of a diameter of about 50 nm give rise to a domain-like appearance in the sample. In addition, rods and needles with a wide range of dimensions up to several microns appear distributed in the surface. The influence of ball milling of the starting powder on the formation of the needles is investigated. Cathodoluminescence in the scanning electron microscope has been used to characterize the sintered samples.

Fabrication of low dimensional structures of ZnSe and ZnO by thermal and mechanical methods

“…This contrast could be associated to an increase of defect concentration around twins which could easily appear in the intersection of the branch with the main steam [24]. Similar behaviour has been observed in other materials as CdSe [14]. In many cases, instead of the pencil like shape shown in Figs.…”

“…2c). The CL distribution shows that the core of the crystals is darker, an opposite behaviour to that found from hollow structures of several semiconductors [14,25] in which the inner part is much brighter. Closest to the gas inlet, nanocombs, and nanoneedles are obtained.…”

“…In this work, a different method for growing elongated nanostructures and microstructures, namely sintering of compacted powder under an argon flow, has been used. This method, which has been recently reported for nanostructures of CdSe [14] and SnO2 [15], leads to the growth of the structures directly on the sample surface, which acts as source as well as substrate . In this work we compare the results obtained with both growth methods (ball milling and VS) in two different compounds of the II-VI family, namely ZnSe and ZnO.…”

Characterization, Cathodoluminescence, and Field‐Emission Properties of Morphology‐Tunable CdS Micro/Nanostructures

“…It is a useful technique for the characterization of the optical properties of nanostructure because of its high spatial resolution and structural information obtained by using secondary electron (SE) imaging. [9][10][11][12][13][14][15] Field-emission (FE) is based on the physical phenomenon of quantum tunneling, during which electrons are injected from a material surface into a vacuum under the influence of an applied electric field. Since the discovery of carbon nanotubes (CNTs), much attention has been paid to the prospects of 1D micro/nanostructures as field emitters because of their low work functions, high aspect ratios, high mechanical stabilities, high conductivities, and so forth.…”

Low-temperature photoluminescence imaging and time-resolved spectroscopy of single CdS nanowires

“…Previous cathodoluminescence measurements of single CdSe needles, 5 ZnSe nanorods 6 and ZnO nanowires 7 have indicated that morphology can influence their emission. Here, direct optical imaging of a number of single VLS-prepared CdS nanowires reveal two distinct types of emission: a spectral band emitting at energies associated with free and bound exciton emission from CdS, and spatially localized states at lower energy which we relate to morphological irregularities of the nanowires.…”