SbSI Single Crystals Research Articles

Dielectric and electrical properties of SbSI and SbSeI single crystals in the region of antiferroelectric phase transition

Experimental results have shown that the capacitance (dielectric permittivity) and electrical conductivity of SbSI and SbSeI crystals along the c(z)-axis change significantly in the region of the antiferroelectric phase transition when DC voltage is applied. An electric field changes the form of B1u (A1) soft mode potential in sites of Sb atoms, which turns the antiferroelectric phase into an induced ferroelectric phase. Degenerate energy levels then split into non-degenerate levels due to electron–phonon interaction (pseudo Jahn–Teller effect), while a narrowed band gap simultaneously creates strong and abrupt changes in C(T) and σ(T).

Growth of large SbSI crystals

Abstract In this paper a novel method of SbSI single crystals fabrication is presented. In this method a sonochemically prepared SbSI gel is used as an intermediate product in a vapour growth process. The main advantages of the presented technique are as follows. First, the SbSI gel source material has lower temperature of sublimation and allows to avoid explosions during SbSI synthesis (the sonochemical synthesis is free of any explosion hazard). Second, but not least, the grown SbSI single crystals have smaller ratio of longitudinal and lateral dimensions. The cross sections of the presented crystals are relatively large (they are up to 9 mm2). The crystals have been characterized by X-ray diffraction, angle-resolved optical spectroscopy, and diffusive reflectivity.

Mobility of Ferroelectric Domains in Antimony Sulfoiodide

Nowadays, there is a growing interest in application of ferroelectric semiconductors in electronics, e.g. in diodes, photodiodes, and ferroelectric random access memories [1, 2]. Antimony sulfoiodide (SbSI) is a promising semiconducting ferroelectric with interesting properties, e.g. piroelectric, pyrooptic, electrooptic, and gas sensing. For the first time mobility of ferroelectric domains in SbSI has been determined using optical transmittance near Curie temperature (TC=293 K) due to different optical energy gaps in ferroelectric and paraelectric phases as well as due to scattering of light on the domain borders. The investigated SbSI single crystals have been grown from vapour phase and equipped with electrodes. Various electric fields have been applied along the c-axis of the crystals. Motion of the domain borders have been recorded using Carl Zaiss Stemi 2000C microscope equipped with Olympus DP25 digital camera. Least square fitting of the linear dependence of velocity of domain borders on electric field (Fig. 1) allowed to determine mobility =8.11(44)·10 -8 m 2 /Vs.

A new heterostructures fabrication technique and properties of produced SbSI/Sb2S3 heterostructures

A new technique for heterostructure fabrication in semiconducting compounds has been proposed. Heterojunctions have been made by applying CO2 laser beam. In contradistinction to currently applied methods (MBE – Molecular Beam Epitaxy and CVD – Chemical Vapor Deposition) the presented technique is simple, of low-cost and very efficient. The new technique has been tested on antimony sulfoiodide (SbSI) single crystals, i.e., a semiconducting, ferroelectric material characterized by many valuable properties. The most important structural, optical and electrical properties of the obtained heterostructures have been presented. Studies have shown that in the CO2 laser treated samples the junction exists between SbSI single crystal and amorphous phase of antimony sulfide (Sb2S3). At room temperature difference between energy gaps of both parts of SbSI/Sb2S3 heterostructure is equal to 0.3eV. This leads to many interesting phenomena and potential applications.

Structural, thermodynamic and phonon properties of SbSI and SbSBr single crystals

The structural, dynamical and thermodynamic properties of antimony sulfoiodide (SbSI) and antimony sulfobromide (SbSBr) are investigated by using an ab-initio pseudopotential method applying density functional theory (DFT) within the local density approximation (LDA). The dynamical properties, such as the phonon dispersion and the phonon density of states, are calculated. Making a factor group analysis we classify the phonon modes. Moreover, the thermodynamic properties, such as the entropy and the constant-volume specific heat, as functions of temperature and the phonon contribution to the free energy and the internal energy are calculated.

Electrical Properties of SbSI/Sb_2S_3 Single and Double Heterostructures

The SbSI/Sb2S3 single heterostructures as well as Sb2S3/SbSI/Sb2S3 and SbSI/Sb2S3/SbSI double heterostructures have been produced by applying CO2 laser treatment of p-type SbSI single crystals. The current voltage and transient characteristics of these heterostructures have been measured in temperatures below and above the SbSI single crystal Curie temperature (Tc = 293 K). The results have been tted with appropriate theoretical formulae to determine the following types of the investigated heterojunctions: P p SbSI/Sb2S3, p P p Sb2S3/ SbSI/Sb2S3 and P p P SbSI/Sb2S3/SbSI. In uence of the illumination on electrical properties of SbSI/Sb2S3 single and double heterostructures has been reported. Fabricated new structures may be potentially applicable in electronics and optoelectronics as a new type of metal ferroelectric semiconductor devices.

X-ray photoelectron spectroscopy of ferroelectric semiconductor SbSI crystals

The paper presents the X-ray photoelectron spectra (XPS) of the valence band (VB) and of the principal core levels from the (110) and (001) planes for the ferroelectric semiconductor SbSI single crystal in the temperature range 215-390 K. The excitation source was Al Kmonochromatic radiation (1486.6 eV). XPS were analysed in the energy range 0-1400 eV. Experimentally obtained energies were compared with the results of theoretical ab initio calculations of surface and bulk atoms in the paraelectric and ferroelectric phases. The structure of VB is calculated and confirmed experimentally. Large shifts (3-5 eV) in the core-level binding energies of surface atoms relative to bulk atoms have been observed. They show a dramatic dependence on the surface crystallographic plane. This is the first observation of XPS shifts of that magnitude in solids. Influence of the phase transition on VB and core levels is studied and the mechanism of the XPS shifts in SbSI crystals is discussed.

Splitting of the XPS in Ferroelectric SbSI Crystals

The paper presents the X-ray photoelectron spectra (XPS) of the valence band and core levels of the ferroelectric SbSI single crystal. Results revealed the new phenomenon--splitting of the core levels at the phase transition temperature T cl . The XPS are measured with monochromatized Al K f radiation in the energy range 0-1400 eV and the temperature range 130-330 K. Experimentally obtained energies are compared with the results of theoretical ab initio calculations. This is the first observation of the splitting of the XPS in a ferroelectric crystal. The mechanism of the XPS splitting in SbSI crystals is discussed.

Interactive branch couple in low frequency regions: A consequence of symmetry and strong anisotropy in SbSI single crystals

In this work we use the minimal band complexes concept for the phonon spectrum modeling of SbSI chain crystal which is proving to be correct in our12 and others calculations of single particle spectra of the current carriers.

Photoinduced polarization reversal jumps in ferroelectric-semiconductor SbSI

The results of a study of photoinduced polarization reversal processes in SbSI single crystals are presented. Simultaneous switching current and Barkhausen effect measurements were used in the experiment. It is shown that the illumination of the SbSI crystal with electric field applied results in an occurrence of Barkhausen jumps provided the light corresponds to the photosensitive spectral region. In crystals with constricted hysteresis loop the illumination causes polydomainization on a level with poling, whereas in crystals without loop constriction only poling processes are initiated. It is established that illumination accelerates the processes of poling and depoling, quantitative characterization of which is presented. The phenomena connected to the influence of the illumination on polarization processes (poling in weak fields, depoling in strong fields, acceleration of the attainment of the polarization steady state) depend to a large extent on the instant of illumination switching on as related to...

Impurity optical absorption of SbSI: Ni single crystals

Single crystals of SbSI and SbSI: Ni were grown by the Bridgman technique. The optical absorption spectra of these single crystals were investigated, and also the electronic states of nickel impurity in the SbSI: Ni single crystal were identified. We observed the impurity absorption peaks at 4502, 7770, 8904, 9090, 12 180 and 14 598 cm −1 due to the electron transitions between the energy levels of Ni 2+ ions sited at T d symmetry of SbSI host lattice. The crystal field parameter and the Racah parameter are given by Dq = 327 and B = 663 cm −1, respectively.

Optical properties of SbSi: Co and SbSeI: Co single crystals

Single crystals of SbSI: Co and SbSeI: Co were prepared by the Bridgman technique. The optical absorption spectra of these single crystals were investigated in the wavelength range 500–2500 nm. We determined the optical energy gaps of these compounds, and identified the electric states of cobalt impurity in these single crystals. We observed the impurity absorption peaks at energies of 14000-4000 cm −1 range due to cobalt impurity. It can be explained that the impurity absorption peaks are attributed to the electronic transitions between the energy levels of cobalt ions, which are sited in tetrahedral ( T d ) symmetry of crystal lattice as Co 3+ and Co 2+ ions. The crystal field parameters Dq are given by 697 cm −1 for Co 3+ and 454 cm −1 for Co 2+ ions in SbSI: Co single crystals, and also 847 cm −1 for Co 3+ and 452 cm −1 Co 2+ ions in SbSeI: Co single crystals.

Growth of SbSI and BiSI from vapour by iodine transport

SbSI and BiSI single crystals were grown from vapour by iodine transport for different temperature gradients. Small platelets and needles of SbSI and needles, polycrystalline boules and platelets of BiSI were obtained.

Crystal growth of SbSI from the vapour phase

Large column-like crystals of SbSI were obtained from the vapour phase at a lower temperature of 320°C than previously reported. These columns, around 5×5×25 mm 3 in dimensions, have flat surfaces and no macroscopic defects like hollows. The largest surfaces were the (110) planes. To investigate the growth process, a system controlled by a microcomputer was produced. It enabled one to observe the shape of a growing crystal at regular intervals for a long period; e.g. every two hours for several weeks. The crystal shape proved to be determined at the earliest stage of growth. Almost all the SbSI components in the source materials were found to be transported to the growth zone and to crystallize as SbSI single crystals after 30 days.

The Influence of Surface Perfection on Photoconductivity in SbSI Single Crystals

physica status solidi (a)Volume 72, Issue 1 p. K9-K10 Short Note The Influence of Surface Perfection on Photoconductivity in SbSI Single Crystals A. Kidawa, A. Kidawa Institute of Physics, Silesian Technical University, Gliwice Search for more papers by this authorR. Witula, R. Witula Institute of Physics, Silesian Technical University, Gliwice Search for more papers by this author A. Kidawa, A. Kidawa Institute of Physics, Silesian Technical University, Gliwice Search for more papers by this authorR. Witula, R. Witula Institute of Physics, Silesian Technical University, Gliwice Search for more papers by this author First published: 16 July 1982 https://doi.org/10.1002/pssa.2210720144 Ul. Krzywoustego 2, 44100 Gliwice, Poland. AboutPDF ToolsRequest permissionExport citationAdd to favoritesTrack citation ShareShare Give accessShare full text accessShare full-text accessPlease review our Terms and Conditions of Use and check box below to share full-text version of article.I have read and accept the Wiley Online Library Terms and Conditions of UseShareable LinkUse the link below to share a full-text version of this article with your friends and colleagues. Learn more.Copy URL Share a linkShare onFacebookTwitterLinkedInRedditWechat No abstract is available for this article. Volume72, Issue116 July 1982Pages K9-K10 RelatedInformation

Temperature dependence of antimony l1 absorption edge of sbsi near tc

In order to study the possible influence of the paraelectric-ferroelectric phase transition on the onset of the X-ray absorption edges, for the first time the temperature dependence of the L1 absorption edge of the Sb ion in SbSI single crystals near Tc has been measured. This paper presents the preliminary results obtained at the new synchrotron radiation source at the Italian storage-ring ADONE of the INFN National Laboratory of Frascati.

Piezoelectric SbSI: Polymer composites

Abstract Following the principle of connectivity in two phase systems, composites of SbSI and Spurrs epoxy in 1:3 and 3:3 modes were prepared. Piezoelectric strain coefficients d 33 and d h, and dielectric constant K were measured over a temperature range encompassing the transition temperature. Interactions between the polymer and SbSI cause a shift in the dielectric peak to higher temperatures. The hydrostatic voltage coefficient g h, ≃ 110 × 10−3 m 2/C and hydrophone sensitivity d h·gh ≃ 10−10 m 2/N are substantially higher than those of SbSI single crystals and most other piezoelectrics.

Pyroelectricity in SbSI

Abstract Large pyroelectric coefficient (1.2 × 104 μC/m2°C at T − Tc ≃ 2°C) in single crystals of SbSI were measured over a temperature range encompassing the ferroelectric phase transition. Simultaneous measurement of the pyroelectric and dielectric constants-were made and the pyroelectric figure of merit p/K was evaluated at various temperatures.

The influence of x-irradiation on the electrical properties of SbSI crystals

An investigation of the electrical conductivity of irradiated SbSI single crystals shows its sensitivity to x-radiation. The influence of the x-radiation on the crystal appears to be a function of the temperature of the SbSI specimen. The absence of the shift of T0 and the reduction of emax in the SbSI crystal specimens during and after long x-irradiation suggests that x-radiation does not cause structural changes in the specimen.

Crystal growth of antimony sulphur iodide

Single crystals of SbSI have been grown from SbI 3 flux by directional cooling through a temperature gradient. The morphology of the crystals is found to be dependent on the growth parameters: (1) composition of the mixture of Sb 2S 3 and SbI 3 flux; (ii) temperature gradient, and (iii) rate of lowering (or cooling). Single crystals highly oriented parallel to the ferroelectric c-axis can be produced by this method in the form of fine parallel needles, thin parallel plates and larger size plates. Characterization information and a brief description of some applications for the single and polycrystal forms produced are given.