An ellipsometer with switching of orthogonal polarization states is described, whose main feature is the use of a dual radiation source and Glan–Thompson polarization prisms from calcite with mixing and separation of orthogonally polarized beams. High reproducibility and stability of measurements of ellipsometric parameters Ψ and Δ in the spectral range of 400–2200 nm were achieved. With an integration time at each point of 2 s, the rms noise at a wavelength of 800 nm and a silicon oxide thickness of 450 nm for Ψ and Δ was 0.0025° and 0.016°, respectively. The RMS noise at a wavelength of 1800 nm and a silicon oxide thickness of 513 nm for Ψ and Δ was 0.005° and 0.03°, respectively.

Abstract—Spectral and temperature dependences of the magneto-optical transversal Kerr effect (TKE) of GaMnAs layers prepared by different methods are reported in this work. The GaMnAs layers prepared by pulsed laser sputtering at 300°С demonstrate a ferromagnetic behavior below 80 K, which is due to the presence of local ferromagnetic (Ga,Mn)As areas in the paramagnetic matrix. The Ga(In)MnAs layers prepared by ion implantation and subsequent pulsed laser annealing were found to exhibit a high TKE response at low temperatures. The presence of the characteristic band in the TKE spectrum in the range of transitions near the L point of the band structure of Ga(In)As confirms the intrinsic ferromagnetism. The temperature dependences of TKE measured for different spectrum ranges demonstrate nonmonotonic behavior, which indicates the magnetic inhomogeneity of the layers. The peculiarities of the magneto-optical spectra of GaMnAs, which were not observed previously, were explained by taking the magnetic and phase inhomogeneity of the layers into account. The sensitivity of TKE to the phase inhomogeneity of the Ga(In)MnAs layers and the efficiency of TKE in studying the electron spectrum and magnetic structure of diluted magnetic superconductors are demonstrated.

A set of monocrystalline B2Te3-xSex films of various compositions were synthesized by metalorganic vapor epitaxy. The smooth films with thicknesses of about 500 nm were grown on (0001) Al2O3 substrates at 465 °C using trimethylbismuth, diethyltellurium and diisopropylselenium as meta-organic precursors. The epitaxial nature of the films and their rhombohedral crystal structure are confirmed by X-ray studies and Raman spectroscopy. The elemental composition of the films was determined by energy dispersive X-ray spectrometry. Optical properties of Bi2Te3-xSex films were examined in the 260-1000 nm range by multi-angle spectroscopic ellipsometry (SE). It was shown that the optical properties of Bi2Te3-xSex films vary monotonically depending on the ratio of selenium to tellurium. It is demonstrated that SE can be used for rapid assessment of the composition of Bi2Te3-xSex films.

Ga-1 xMnxAs layers prepared by ion implantation and subsequent pulsed laser annealing with the planned Mn concentrations of x = 0.01-0.08 have been studied using the magneto-optical transversal Kerr effect (TKE) and spectral ellipsometry. The spectral dependences of the diagonal and nondiagonal components of the permittivity tensor (PT), as well as the spectrum of magnetic circular dichroism (MCD) have been calculated for the layers. The obtained spectra of the diagonal PT components show that the layers under study maintain the zinc-blende crystal structure of the parent GaAs semiconductor. All studied samples reveal a strong TKE response at low temperatures with a dependence of an effective Curie temperature (at which TKE appears) on the Mn concentration. A number of extrema in the low-temperature TKE and MCD spectra are close to the energies of transitions in the Gamma and L critical points of the parent semiconductor band structure that confirms the intrinsic ferromagnetism of the Ga-1 xMnxAs layers. The MCD spectra shape and its change with Mn concentration increasing are discussed on a base of the valence-band model of ferromagnetism in DMS. (C) 2017 Published by Elsevier B.V.

Measurement and calculation results are presented that confirm that design four-mirror compensators can be designed for the spectral range of 200–2000 nm that is widely used in modern spectral ellipsometers. Measurements and calculations according to standard ellipsometric programs have been carried out on a broadband LED spectral ellipsometer with switching of orthogonal polarization states. Mirrors with the structure of glass substrate/Al 2 O 3 layer (20–30 nm thick)/Al layer (150 nm thick)/upper Al 2 O 3 layer (with specified thickness d ) have been prepared by vacuum-evaporation method. It is shown that the phase-shift spectra of a four-mirror compensator, two mirrors of which have a native oxide 5.5 nm thick and the two others of which have an oxide layer 36 nm thick, measured on the ellipsometer, are flattened in comparison with similar spectra of a compensator, all four mirrors of which have a native oxide, especially in the short-wavelength spectral region. The results of calculating the phase-shift spectra of the four-mirror compensator with six variable parameters (angles of incidence of radiation on the mirrors and thicknesses of oxide layers on four mirrors) are presented. High-quality achromatization in a wide spectral range can be achieved for certain sets of parameters.

A light-emitting diode (LED) magneto-optical ellipsometer with the switching of orthogonal polarization states is described. The distinctive features of the ellipsometer are the implementation of the maximally deep azimuthal modulation, application of two-channel detector, use of a set of LEDs ensuring a high signal-to-noise ratio, and the absence of moving polarization elements. These features have substantially increased the precision of measurements of ellipsometric parameters ψ and Δ for ferromagnetic materials and their changes (δψ and δΔ) in the magnetic field, which are connected for the transverse Kerr configuration by simple relations with magneto-optical parameters. At wavelengths of 365, 372, 390, 405, 420, and 465 nm, the precision of ψ-δψ and Δ-δΔ measurements of metal films is about 0.0003° and 0.001°, respectively. The spectral resolution is 4 nm; the minimal measurement time of ψ and Δ in the continuous spectral range of 270–1000 nm is 20 s; the magnetic field is varied from–2500 to +2500 Oe; and the step of the magnetic field setting is 0.5 Oe.

This paper describes an LED ellipsometer with a continuous wavelength range of 260-1000 nm and good technical characteristics. The measurement reproducibility and stability of the ellipsometric parameters Psi and Delta of silicon with intrinsic dioxide at the peak wavelengths of the LED radiation are no worse than 0.001 and 0.01 degrees, respectively. At wavelengths of 365, 375, 390, 405, 420, and 465 nm, the reproducibility of the Psi and Delta measurements of metal films is around 0.0003 and 0.001 degrees, respectively. The spectral resolution is 4 nm. The minimum time to measure Psi and Delta in the entire wavelength range is 20 s. (C) 2016 Optical Society of America.

Описан светодиодный магнитооптический эллипсометр с переключением ортогональных состояний поляризации, отличительными особенностями которого являются: реализация максимально глубокой азимутальной модуляции, применение двухканального детектора, использование набора светодиодов, обеспечивающих высокое отношение сигнал/шум, и отсутствие движущихся поляризационных элементов. Эти особенности позволили существенно повысить воспроизводимость измерений эллипсометрических параметров Ψ и Δ ферромагнитных материалов, а также их изменений (δΨ и δΔ) в магнитном поле, связанных для поперечной конфигурации Керра простыми соотношениями с магнитооптическими параметрами. На длинах волн 365, 372, 390, 405, 420 и 465 нм воспроизводимость измерений Ψ, δΨ и Δ, δΔ пленок металлов составила около 0.0003° и 0.001° соответственно. Спектральное разрешение равно 4 нм; минимальное время измерения Ψ и Δ в непрерывном спектральном диапазоне 270–1000 нм составило 20 с; величина магнитного поля изменяется в диапазоне от –2500 до +2500 Э; дискретность установки магнитного поля 0.5 Э.

The results of study of the dielectric loss at millimeter (MM) wavelengths range and temperatures 300-950 K in two different diamonds grown by the arc plasma jet (APJ) technology are presented. The electrophysical properties and parameters of point defects are also investigated. A comparison of results was made for these samples with the diamonds which have been grown by the technology of microwave plasma chemical vapor deposition (MPCVD).It is revealed that both frequency and temperature loss dependences as well as the electrophysical properties and parameters of point defects in the APJ diamonds essentially differ from the MPCVD diamonds properties.Also these properties in the studied APJ diamonds also essentially differ.The dielectric loss mechanisms are discussed.

The use of a set of eight light-emitting diodes (LEDs) in a multichannel spectral ellipsometer with binary modulation of the polarization state allowed the development of a simple ellipsometer with a fully spanned wavelength range of 350–810 nm and high performance characteristics. The obtained reproducibility and stability of measurements of the ellipsometric parameters Ψ and Δ are 0.01° and 0.03°, respectively. The minimum times of measuring Ψ and Δ in the wavelength range of 435–690 nm and in the total range of 350–810 nm are 0.5 and 5 s, respectively.

Использование набора из 8 светодиодов в многоканальном спектральном эллипсометре с бинарной модуляцией состояния поляризации позволило создать простой эллипсометр с полностью перекрывающимся диапазоном длин волн 350–810 нм и высокими техническими характеристиками. Воспроизводимость и стабильность измерений эллипсометрических параметров Ψ и Δ – 0.01° и 0.03° соответственно. Минимальное время измерения Ψ и Δ в диапазоне длин волн 435–690 нм – 0.5 с, в полном диапазоне длин волн 350–810 нм – 5 с.

A modification of the plasma-chemical reactor based on beam-plasma discharge is developed for the deposition of carbon (including diamond-like carbon (DLC)) films. The reactor differs from the existing devices by the simplicity of the procedure that makes it possible to control the energy characteristics of the ion beam incident on the film in the course of deposition. A method for the computer simulation of the parameters of the ion flux on an electrically insulated surface upon the modulation of the plasma potential is proposed. The method allows the prediction of the ion energy and ion flux that acts upon the deposited film. DLC films on metal substrates are produced. The charge deep-level transient spectroscopy is used to reveal the effect of the adsorbed water and alcohol vapors on the electrophysical properties of the films, which indicates that the films can be used as active adsorbing materials in chemical sensors.

Sensitive and selective chemical sensor based on carrier transfer in metal/NPC/SiO2/p-Si structure with nanoscale metal and nanoporous carbon adsorbed layers were fabricated and studied. It was found that most powerfully and noticeably adsorbed molecules influence on whole injection from p-Si substrate on border traps in SiO2 layer and energy spectrum of trapping centers that lead to changes of sensor electrical characteristics. The most adsorption effect was found in Q-DLTS spectra. Moreover adsorption of the molecules of the different gases (vapor) induced different spectra changes. Physical model of the operating the chemical sensor was proposed and discussed. Got results are indicative of possibility of the fabrication sensitive and selective MIS chemical sensors using for detected of adsorbed molecules the isothermal Q-DLTS as sensing method.

The native and impurity induced point defects in undoped chemi-cal-vapor deposited diamond, high-purity semi-insulating SiC and grown by molecular beam epitaxy GaN were investigated by isothermal charge-based deep level transient spectroscopy (Q-DLTS). It was found that deep levels in undoped diamond have a continuous energy spectrum with two maximums at energies 0.71 and 0.54 eV. Several discrete deep levels were found in SiC. Defect level E1 is attributed to atom displacement on the carbon sublattice in SiC. Levels E2, E4 are related to (Vc - Vsi) complex and silicon vacancy Vsi, respectively. Obtained values of active-tion energy and capture cross-section allow expecting that deep level E3 associated with the carbon vacancy Vc, while acceptor level En is vanadium-induced level. Eight deep levels were observed in GaN. Levels E1, E2, E7, and E8 have been observed in low doped n-GaN are characterized for the first time in our studies.

The results of complex investigation of dielectric parameters at millimeter wavelengths range and defects are presented for the diamond prepared by the DC arc plasma jet (APJ) technique. Also a comparison with conventional CVD diamonds grown by microwave plasma chemical vapor deposition (MPCVD) technique was made. It was found that the dielectric loss in the APJ diamond increases with frequency while it decreases in MPCVD diamonds. It corresponds to the mechanism of the lattice loss induced by lattice disorder in the APJ diamond. The activation energies of the conductivity and energy spectrum of the defect levels were studied. As follows from the data obtained by the charge-based deep level transient spectroscopy (Q-DLTS), all diamonds have significant defect concentrations with continuous energy spectrum. However the concentration of shallow levels is significantly more in APJ diamond. A correlation between the observed defect parameters and values of dielectric parameters was found.

Laser fabrication of micrometer-scale graphitic structures in the bulk of monocrystalline CVD diamond was investigated. Ultra-short (1ps) pulses of Ti:sapphire laser were tightly focused inside the sample. Initiation of graphitization in the focal volume and propagation of graphitization front towards the laser beam are considered. Electrical resistivity of the produced graphitic material was measured (3.6–3.9Ωcm). Problems and strategies of 3D laser writing are discussed paying special attention to graphitization homogeneity, minimization of the wire diameter, control of the structure shape and reduction of the surrounding diamond damage. Laser fabrication of complex microstructures including pillars, plates, hexagonal chain and periodic arrays of straight wires has been demonstrated.