Growth and spatially resolved luminescence of low dimensional structures in sintered ZnO

Abstract

Sintering of ZnO pressed powder under Ar flow at temperatures between 1250 and 1300 • C leads to the formation of elongated microstructures and nanostructures, with different morphologies, on the sample surface. Rods and needles with cross-sectional dimensions ranging from tens of nanometres to several tens of microns and up to hundreds of microns in length are obtained. In an advanced stage of growth, nanoneedles are frequently arranged in bundles, forming the walls of tubes with different cross-sectional dimensions. In addition, microcombs and microfeathers consisting of well oriented nanoneedles are observed. Cathodoluminescence (CL) in the scanning electron microscope (SEM) has been used to characterize the structures grown. The formation of the elongated structures causes spectral changes, in particular an enhancement of the green-orange luminescence. High CL emission from the internal surface of the tubes has been observed.

Growth and luminescence of elongated In2O3 micro- and nanostructures in thermally treated InN

“…[5][6][7] In the present work, In 2 O 3 elongated micro-and nanostructures have been grown by thermal treatment of compacted InN powder under argon flow. This method has been previously reported to lead to the growth of elongated nanostructures, of different semiconductor oxides [8][9][10][11] and of CdSe 12 on the surface of the sample so that neither catalyst nor a foreign substrate is used. The obtained structures have been characterized by x-ray diffraction ͑XRD͒, scanning electron microscopy ͑SEM͒, x-ray microanalysis in SEM and cathodoluminescence ͑CL͒ in SEM.…”

Thermal growth and structural and optical characterization of indium tin oxide nanopyramids, nanoislands, and tubes

“…This method has been previously reported to lead to the growth of elongated structures of different semiconductor oxides on the surface of the sample, so that neither a catalyst nor a foreign substrate is used. [8][9][10][11][12][13] In Ref. 8, the growth of SnO 2 microand nanotubes with rectangular cross section was reported, while in the case of In 2 O 3 , 11 wires, necklace-and arrowshape structures were grown from InN.…”

Indium-zinc-oxide nanobelts with superlattice structure

“…In fact, nanorings were not observed in our previous works on growth, under the same conditions applied here, of elongated nanostructures of ZnO undoped and doped with different elements. [14][15][16] As Figs. 2͑b͒ and 2͑c͒ show, the angle between the superlattice layers and the growth axis is not constant along the belt, but it changes from nearly 90°to about 45°, showing that the crystallographic growth direction of the belt gradually deviates from ͓0001͔, which is the direction perpendicular to the layers.…”

“…However, the ZnO defect band is a very broad complex band extending in the approximate range 2.0-2.8 eV, while the 2.37 eV band of the In-Zn-O structures is within the range 2.3-2.5 eV with a full width at half maximum of 0.15 eV, much narrower than the usually reported defect band of ZnO, specially in CL spectra of nanostructures. 14,18 The 2.37 eV appears to be characteristic of the In-Zn-O compound forming the plates and nanobelts. There is, however, no information enabling to associate this emission with specific electronic features of Zn 4 In 2 O 7 .…”