In this paper we demonstrate a nanofabrication technique based on local ion irradiation of silicon dioxide with a focused helium ion beam. The wet etching of silicon dioxide irradiated with a focused helium ion beam is described in a two-dimensional case both numerically and experimentally. We suggest a model for the etching process based on the distribution of ion induced defects in the irradiated material.
View Article and Find Full Text PDFJ Opt Soc Am A Opt Image Sci Vis
September 2019
Periodical spatial modulation of the excitonic resonance in a quantum well could lead to the formation of a new highly directional and resonant coherent optical response-resonant diffraction. Such excitonic diffraction gratings were demonstrated in epitaxially grown quantum wells patterned by low-dose ion beam irradiation before or after the growth. In this paper we present a theoretical model of the resonant diffraction formation based on the step-by-step approximation of the Maxwell equation solution.
View Article and Find Full Text PDFA diagnostic system for plasma radiated power tomography on Globus-M was upgraded with a new linear array based on silicon photodiodes. The hardware of the diagnostic system based on a 256-channel tangential matrix array and a 24-channel linear array is described. The algorithm for 2D tomographic reconstruction of plasma emissivity is presented.
View Article and Find Full Text PDFWe present the results of magnetic force microscopy investigations of domain structures in multilayer [Co (0.5 nm)/Pt (1 nm)]₅ thin film structures (denoted hereafter as Co/Pt) modified by additional Co capping layers and by ion irradiation. It is demonstrated that a Co capping layer essentially changes the domain structure and decreases the threshold of magnetization reversal, due to the formation of noncollinear magnetization in Co/Pt.
View Article and Find Full Text PDFWe propose a method of spatial modulation of inhomogeneous broadening of a quantum-well excitonic resonance based on local generation of defects produced by a focused ion beam. The method is applied to fabrication of excitonic diffraction grating in a single quantum-well InGaAs/GaAs structure by irradiating the sample with a beam of 35-keV He ions of exposure doses <10 cm. The spectrum of resonant diffraction on such a structure is narrower than that of reflectivity and decreases much faster with increasing temperature.
View Article and Find Full Text PDFThere are two types of intrinsic surface states in solids. The first type is formed on the surface of topological insulators. Recently, transport of massless Dirac fermions in the band of "topological" states has been demonstrated.
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