Nanopatterning Au chips for SPR refractometer by using interference lithography and chalcogenide photoresist

This study reports on development of the interference lithography (IL) technique applying the resist based on chalcogenide glass films for fabrication of gold chips in the nform of periodic surface nanostructures for surface plasmon resonance (SPR) refractometers. The IL technique was optimized for patterning the Au layers and formation of one-dimensional (grating) structures with the spatial frequency close to 3300 mm⁻¹. The spatial frequency and depth of grating grooves were selected with account of the condition for Bragg reflection of plasmons at the operation wavelength of SPR refractometer and given environment (which is a condition for enhancing biosensor sensitivity as compared to that of a flat Au chip surface). It has experimentally been demonstrated that the use of diffraction patterns in SPR sensor increases its response by 17%

Structure and optical properties of AlN films obtained using the cathodic arc plasma deposition technique

Aluminum nitride (AlN) film coatings have been obtained by a new technique of hybrid helikon-arc ion-plasma deposition. Possibility to combine the magnetic-filtered arc plasma deposition technique with a treatment in RF plasma of helicon discharge allowed us to deposit AlN coatings on thermolabile substrates, significantly increasing the deposition rate. A study of spectral properties of AlN films (reflection and transmission spectra within the range 2…25 µm) has been carried out by using the infrared Fourier spectrometer Spectrum BX-II. It has been shown that the obtained composite structures (AlN coatings on teflon and mylar substrates) could be used as passive filters in the infrared spectral range

Optimization of bromine-emerging etching compositions K₂Cr₂O₇-HBr-ethylene glycol for forming a polished surface of CdTe, ZnxCd₁-xTe and CdxHg₁-xTe

The chemical dissolution of the CdTe single crystals and ZnxCd₁-xTe , ZnxCd₁-xTe solid solutions in aqueous solution of K₂Cr₂O₇-HBr-ethylene glycol in reproducible hydrodynamics conditions has been investigated for the first time. The graphic dependences &qout;etchant concentration - etching rate&qout; have been charted and determined the concentration limits of polishing etchant. It was demonstrated that the dissolution process of these materials is limited by the diffusion stages. The influence of the nature of the solid solutions of the ZnxCd₁-xTe and CdxHg₁-xTe on the rate and character of their chemical etching was established. The etchants composition and condition of realization of chemical-dynamic polishing process of these semiconductors were optimized

Chemical polishing of InAs, InSb, GaAs and GaSb

The mechanism and kinetics of chemical dissolution of InAs, InSb, GaAs and GaSb in (NH₄)₂Cr₂O₇-HBr-C₄H₆O₆ etching mixtures have been studied. Influence of tartaric acid on the parameters of chemical-dynamic polishing and morphology of the obtained crystals surface has been determined. Using of (NH₄)₂Cr₂O₇-HBr-C₄H₆O₆ etching solutions provides the controlled removal of thin layers and the polishing of investigated semiconductors. The polishing etchant compositions have been proposed and conditions for the chemical-dynamic polishing of the InAs, InSb, GaAs and GaSb crystals have been optimized

Chemical-dynamic polishing of InAs, InSb, GaAs and GaSb crystals with (NH₄)₂Cr₂O₇-HBr-citric acid etching composition

The chemical dissolution of InAs, InSb, GaAs and GaSb crystals in (NH₄)₂Cr₂O₇-HBr-C₆H₈O₇ etching solutions has been investigated. The dissolution rate of the semiconductor materials has been measured as a function of etchant composition, stirring rate and temperature. The limiting stages of dissolution process, regions of the polishing and unpolishing solutions have been established. The polishing etchant compositions and conditions for chemical-dynamic polishing of the InAs, InSb, GaAs and GaSb crystals have been proposed and optimized

Investigation of superlattice structure parameters using quasi-forbidden reflections

We studied possibilities of a nondestructive X-ray technique for testing short-period strained GaAs-AlAs superlattices. An analysis of the quasi-forbidden 200 reflections may be used for determination of superlattice layer structure parameters and sublayer thickness. The effect of irregularity of superlattice transition region on X-ray diffraction reflection curves and elastic strains in layers was studied

The influence of substrate temperature on properties of Cu-Al-O films deposited using the reactive ion beam sputtering method

For the first time, Cu-Al-O films were grown using the reactive ion beam sputtering at temperatures ranging from 80 to 380 °C in 50 °C increments. Correlations between the properties of as-grown films measured by X-ray diffraction, energy dispersive X-ray spectroscopy, atomic force microscopy, Fourier transform infrared spectrometry and optical transmission measurements have been discussed. It was shown that the increase of substrate temperature caused formation of the CuAlO2 phase. Additional optimization of technological parameters of growth and post-growth temperature annealing are necessary to obtain single-phase CuAlO2 films