Formation of nanoripples on ZnO flat substrates and nanorods by gas cluster ion bombardment

Funding Information: This work was supported by the National Natural Science Foundation of China under grant 11875210, the Science and Technology Planning Project of Guangdong Province under grant 2018A050506082, China Postdoctoral Science Foundation under grant 2019M652687, and by the grant RFBR No.19-05-00554 in the part of the development of advanced approach to analysis of geochemical objects.In the present study Ar+ cluster ions accelerated by voltages in the range of 5-10 kV are used to irradiate single crystal ZnO substrates and nanorods to fabricate self-assembled surface nanoripple arrays. The ripple formation is observed when the incidence angle of the cluster beam is in the range of 30-70°. The influence of incidence angle, accelerating voltage, and fluence on the ripple formation is studied. Wavelength and height of the nanoripples increase with increasing accelerating voltage and fluence for both targets. The nanoripples formed on the flat substrates remind of aeolian sand ripples. The ripples formed at high ion fluences on the nanorod facets resemble well-ordered parallel steps or ribs. The more ordered ripple formation on nanorods can be associated with the confinement of the nanorod facets in comparison with the quasi-infinite surface of the flat substrates.publishersversionpublishe

Purification of liquid indium by electric current-induced impurity migration in a static transverse magnetic field

We have developed an original method for indium purification. Our approach is based on the directional transfer of impurities by applying crossed electric and magnetic fields to the melting volume. The method reduced the concentration of nickel and tin by a factor of 10 while copper was reduced by a factor of 3. A simple hydrodynamic mass transport model describing the process was also derived

Sputtering of silicon nanopowders by an argon cluster ion beam

In this work an Ar+ cluster ion beam with energy in the range of 10–70 keV and dose of 7.2 × 1014–2.3 × 1016 cluster/cm2 was used to irradiate pressed Si nanopowder targets consisting of particles with a mean diameter of 60 nm. The influence of the target density and the cluster ion beam parameters (energy and dose) on the sputtering depth and sputtering yield was studied. The sputtering yield was found to decrease with increasing dose and target density. The energy dependence demonstrated an unusual non-monotonic behavior. At 17.3 keV a maximum of the sputtering yield was observed, which was more than forty times higher than that of the bulk Si. The surface roughness at low energy demonstrates a similar energy dependence with a maximum near 17 keV. The dose and energy dependence of the sputtering yield was explained by the competition of the finite size effect and the effect of debris formation

Surface composition of Cd1-xFe(Mn)(x)Te1-ySey systems exposed to air

Using X-ray induced Photoelectron Spectroscopy, Time of Flight Secondary Ion Mass Spectrometry and Atomic Force Microscopy we have investigated elemental composition, structure and oxidation process taking place at the surfaces of polycrystalline Cd0.99Fe0.01Te0.97Se0.03 and Cd0.95Mn0.05Te0.97Se0.03 systems stored in ambient conditions. The surface oxidation destroys the native CdTe matrix and provokes substantial atomic rearrangement in the first few atomic layers. The near surface region of both systems is enriched in Cd and to some extent Te-deficient, but the surface structure, morphology and the native oxide composition are all found to be considerably different. In Cd0.99Fe0.01Te0.97Se0.03 system both Fe and Se dopants diffuse into the bulk and oxidation of its surface results in formation of a thin CdTeO3 layer which covers the CdTe matrix. In Cd0.95Mn0.05Te0.97Se0.03 system oxygen-rich atmosphere triggers Mn and Se out diffusion and the nonuniform oxide layer predominantly consists of MnO and a small amount of Te-oxide which both lay underneath a thin layer of metallic Cd segregated at the top of the surface. (C) 2016 Elsevier B.V. All rights reserved

Sn-deficiency in the electrodeposited ternary CuxSnySz thin films by ECALE

Ternary CuxSnySz thin films with different Cu/Sn atomic ratios and thicknesses have been electro-chemically deposited on the (111) face of a silver single crystal. The surface morphology and chemical composition of these chalcogenides, which have attracted considerable worldwide interest as low cost high conversion efficiency photovoltaic devices, have been characterized by means of SEM, parallel angle resolved (PAR-XPS) and TOF-SIMS depth profiling in order to gain insight into the morphology and element distribution within the layer and their effect on the band gap. This study constitutes the first in-depth chemical study on CuxSnySz thin films, providing evidence of notable discrepancies between the expected and real composition, especially regarding the Cu/Sn ratio. The samples were found to be chemically homogeneous through the whole deposit even though strongly tin depleted regardless their thickness or deposition sequence. Finally, the literature band gap data were discussed on the basis of these findings