Optical fabrication of wide‐gap semiconductor nanoparticles in superfluid helium

Abstract

The nanoparticles have been fabricated from CuCl powder by laser ablation in superfluid helium. We found that most of nanoparticles are CuCl nanocrystals with single‐crystal quality by means of electron diffraction and high‐resolution transmission electron microscope. Moreover, we performed cathodoluminescence spectroscopy of single nanoparticle prepared by laser ablation with use of a scanning electron microscope. I1 bound exciton luminescence which is characteristic in the bulk CuCl was clearly observed in the nanoparticle at 15 K. In addition, we found that the cathodoluminescence spectrum changes by the electron beam irradiation. (© 2009 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)

Fabrication of single-crystalline microspheres with high sphericity from anisotropic materials

“…Superfluid helium exhibits low temperatures, ultralow viscosity, high thermal conductivity, and good transparency in the visible region. It is also chemically inactive and can be used to provide a neutral environment for laser ablation 7 8 . Thus, we expect fabrication of unique structures to be feasible under such extreme conditions.…”

Magnetic trapping of superconducting submicron particles produced by laser ablation in superfluid helium

“…The particles have been analyzed to be single crystalline spherical structure using electron diffraction and transmission electron microscope images. 7,8) On the other hand, this ablation technique has been applied for producing metal nanowire structures 9) and investigating their size effects of superconductivity by measuring directly their electrical resistance. 10) As shown in these reports, laser ablation in liquid helium is one of the effective experimental techniques for producing submicron particles and exploring their quantum size effects.…”