tio2

Abstract

Thumbnail image of graphical abstract

It is proposed to use the variation of the electrolyte temperature to fabricate titania nanotubes with variable inner diameter at a constant outer diameter and an invariable package density. The anodization of Ti sheets in an ethylene glycol and HF containing electrolyte is found to allow the preparation of nanotubes with the inner diameter controlled in the range from 10 nm to more than 250 nm through the change of the electrolyte temperature from –20 °C to +50 °C. The peculiarities of the anodization process performed at low electrolyte temperatures are discussed.

Keywords: titania templates; nanotubes; electrochemistry; self-organization

DOI: 10.1002/pssr.201004069

eliri

Abstract

We report on a technological route allowing one to integrate huge amounts of electrically isolated metal or semimetal (Pb/Sn alloys and Bi) nanowires in glass fibers with the diameter of up to a few hundreds of micrometers and the length reaching 1 m, the nanowires exhibiting a two-dimensional hexagonal distribution in the cross-sectional plane. The obtained results are indicative of new challenges for the elaboration of photonic crystals based on metallo-dielectric periodic and quasi-periodic structures.

Keywords: Nanowires; Fiber technology; Capillary drawing; Nanomaterials; Metallo-dielectric structure

http://dx.doi.org/10.1016/j.matlet.2010.06.002

membr

Abstract

We propose a method of direct visualization of the spatial nanoarchitecture of dislocation networks which is based on etching away the regions with low density of structural defects from the bulk of GaN epilayers, keeping intact only the threading dislocations and a thin surface film pre-treated with low-energy Ar+ ions. The formation of nanometer-thick suspended membrane to which the dislocations are genetically attached provides conditions for the revelation of the spatial nanoarchitecture of dislocation networks using conventional scanning electron microscopy. Complementary monochromatic and panchromatic micro-cathodoluminescence images are presented.

Keywords: Semiconductors; Suspended membrane; Dislocation network; Electron microscopy; Luminescence

http://dx.doi.org/10.1016/j.matlet.2010.10.033

1

Abstract

We report on fabrication of metalnanotubes in semiconductor nanotemplates possessing ordered two-dimensional hexagonal arrays of pores grown in n-InP crystalline substrates using anodic etching in neutral electrolyte. Electrochemical pulsed deposition of arrays of Pt nanotubes with diameters of 70 and 140 nm is demonstrated. The produced metallo-semiconductor tubular structure behaves like a layered nanomaterial allowing one to easily cleave thin films consisting of rows of Pt nanotubes in semiconductorenvelope.

Keywords: Anodic etching; Semiconductor nanotemplate; Electrochemical deposition; Metalnanotubes

http://dx.doi.org/10.1016/j.elecom.2008.02.029

jno

Abstract:

We report on templated fabrication of metal nanotubes by electrochemical pulsed deposition of Pt in InP and ZnSe porous layers with pore diameters from 40 to 400 nm. Ordered two-dimensional hexagonal arrays of pores are produced in n-InP crystalline substrates, and a uniform distribution of pores is realized in n-ZnSe substrates. We demonstrate the possibility to fabricate arrays of pores and networks of embedded metal nanotubes oriented parallel to the top surface of the template. The optical properties of the produced porous materials are studied using Raman scattering and photoluminescence spectroscopy. The prospects for the elaboration of photonic crystal lenses and beam splitters on the basis of two-dimensional metallo-semiconductor structures prepared on porous templates and tubular structures are demonstrated by means of calculation of their photonic properties.
Keywords: SEMICONDUCTOR NANOTEMPLATES; ANODIZATION; METAL ELECTROPLATING; METAMATERIALS; NEGATIVE REFRACTIVE INDEX; FLAT LENS

gan

mrrl602004

Abstract

We report the maskless fabrication of ultrathin suspended GaN membranes designed by focused ion beam treatment of the GaN epilayer surface with subsequent photoelectrochemical etching. This technological approach allows the fabrication of ultrathin membranes, as well as supporting micro/nanocolumns in a controlled fashion. The analysis of the spatial and spectral distribution of microcathodoluminescence demonstrates that the membranes exhibit mainly yellow luminescence. These results pave the way for the fabrication of ultrathin suspended GaN membranes for MEMS/NEMS applications.

Keywords: ultrathin membranes; GaN; focused ion beams; photoelectrochemical etching

DOI: 10.1002/pssr.201206020