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The Cryogenic Underground Observatory for Rare Events (CUORE) is an experiment that will search for neutrinoless double-beta (0&nu&beta&beta) decay of 130Te and other rare processes. Observing 0&nu&beta&beta decay would establish that neutrinos are massive Majorana fermions, demonstrate that lepton number is not conserved, and constrain the neutrino mass scale and hierarchy. The CUORE detector, currently being constructed underground at the Gran Sasso National Laboratory in Italy, is an array of 988 high-resolution TeO2 bolometers. Each bolometer is comprised of a thermistor and a TeO2 crystal that serves as both the source and the detector of 0&nu&beta&beta decay. The 0&nu&beta&beta decay signature for 130Te is a peak at the Q-value 2528 keV. Observation of 0&nu&beta&beta decay requires that the background at the peak be ultra-low. Background-source identification and characterization are therefore extremely important. One source of background that is poorly characterized is activation of the TeO2 crystals by sea-level cosmic-ray neutrons. This process, known as cosmogenic activation, produces long-lived radioisotopes that can obscure the 0&nu&beta&beta peak. Existing cross-section data is insufficient to estimate this background; therefore, an additional cross-section measurement has been performed in which a TeO2 target was irradiated with a neutron spectrum similar to that of cosmic-ray neutrons at sea-level. Analysis of the radionuclides produced reveals that 110mAg will dominate the cosmogenic activation background in CUORE. Estimations using the measured cross section for 110mAg indicate this source will be negligible compared with other contributions to the CUORE background.

TeO2 thin films were deposited by magnetron sputtering method. After deposition, amorphous samples were annealed at various temperatures. Influence of annealing temperature on a presence of crystalline phase was investigated.

Acousto-optic (AO) phase matching condition is determined not only by the optical and acoustic waves propagation direction and parameters, but also by the physical characteristics of the AO interaction medium. Wherein, these characteristics, mainly the acoustic wave velocity, are temperature dependent. The change of ultrasound velocity relies on the medium stiffness constants cij variation with temperature. However, even for the most popular AO material – tellurium dioxide, the values of the stiffness constants temperature coefficients, given in various papers, vary significantly. The experimentally observed AO phase matching frequency temperature shift values do not coincide with those evaluated with literature data. In order to eliminate the observed discrepancy between theory and experiment, the AO phase matching frequency temperature dependencies for several AO cells based on TeO2 crystals with cut angles varying from 1.8° to 19° from the [110] axis in the (1‾10) plane were analyzed. The ultrasound velocity variation temperature coefficients were evaluated and the c11-c12 and c44 temperature coefficients that define the slow acoustic mode velocity in the selected plane were determined.

Tellurium dioxide thin films were deposited by magnetron sputtering method. The XRD analysis of the films annealed at 200, 500, 650 and 700 celsius degree showed appearing of crystalline phase in a higher temeratures.

Tellurium dioxide doped by europium thin films were deposited by magnetron sputtering method and simultaneously heated at 200 oC. Presence of Eu ions and their valence states was confirmed by X-ray photoemission spectroscopy measurements. The structure of the films as well as the influence of europium dopant on crystalline structure of the films was examined by X-ray diffraction method. Morphology of the samples was observed by atomic force microscope. Doping by europium didn’t change structural parameters. Optical measurements showed photoluminescence from both Eu2+ and Eu3+ ions.

Tellurium dioxide based glasses with a low hydroxyl groups concentration were synthesized in an atmosphere of dried oxygen from initial high purity oxides. Large high-quality optical elements were manufactured and investigated from the point of view of nonlinear propagation of ultrashort pulses in the mid-IR range. Optical homogeneity, thermophysical, optical, including nonlinear properties were studied.

The development of the optical frequency comb (OFC) generation and practical application methods is one of the most important and rapidly developing areas of the modern optical electronics. One of the comb types is acousto-optical (AO) OFCs. This type of OFCs is obtained by the multiple passage of an optical signal through a closed loop containing an acousto-optic frequency shifter (AOFS). Despite the fact that AO OFCs have been studied quite intensively lately, the published papers did not focus on the influence of the main element, the AO cell used as AOFS, parameters on the characteristics of the obtained optical comb, primarily on the comb spectral width, number of spectral components and its envelope shape. In this paper, we perform a theoretical analysis of all possiblities in paratellurite crystal wide-angle AO diffraction geometries in order to determine the most suitable for the application as AOFS in a frequency shifting loop.

Bioactive glasses have been widely investigated for their ability to release ions with therapeutic effect. In this paper, a silica based bioactive glass was doped with a low amount of tellurium dioxide (1 and 5 mol%) to confer antibacterial and antioxidant properties. The obtained glasses were characterized in terms of morphology, composition, structure, characteristic temperatures and in vitro bioactivity. Moreover, comprehensive analyses were carried out to estimate the cytocompatibility, the antibacterial and antioxidant properties of Te-doped glasses. The performed characterizations demonstrated that the Te insertion did not interfere with the amorphous nature of the glass, the substitution of SiO2 with TeO2 led to a slight decrease in Tg and a TeO2 amount higher than 1 mol% can induce a change in the primary crystal field. In vitro bioactivity test demonstrated the Te-doped glass ability to induce the precipitation of hydroxyapatite. Finally, the biological characterization showed a strong antibacterial and antioxidant effects of Te-containing glasses in comparison with the control glass, demonstrating that Te is a promising element to enhance the biological response of biomaterials.

The composition of oxide layers that grow under air exposure at room temperature on the surface of SnTe monocrystals was studied by Raman spectroscopy, angle resolved X-ray photoelectron spectroscopy (ARXPS), and Time Of Flight Secondary Ion Mass Spectroscopy (TOF-SIMS). It is established that a multilayered structure with a non-uniform depth distribution of components is formed. The main components of this structure are tin dioxide SnO2 and tellurium in three chemical states - elementary Te, tellurium dioxide TeO2 and tellurium suboxide TeOx (0

The quaternary glass system tellurium dioxide, boron trioxide, silicon dioxide and manganese dioxide where x = 0.00 to 0.05 M fraction has been successfully prepared via conventional melt and quench-casting technique. The density was determined by Archimedes method with distilled water as buoyant liquid. The results showed that the density decreases and molar volume increases with respect to manganese concentration. FTIR spectral studies suggest that glass network is mainly built up of boron trioxide, tetrahedral boron, tellurium trioxide, trioxotellurate and silicon dioxide structural units. The ultrasonic velocities and elastic moduli were recorded using a pulse-echo method at frequency 5 MHz at room temperature. Some other physical properties such as Debye temperature, softening temperature, microhardness, Poisson's ratio, fugacity, fractal bond connectivity and Cauchy relation were determined. Results indicate that these parameters depend upon the composition of the glass system and the dopant concentration, MnO2 inside the glass system.

An effectively large bandgap and a high carrier mobility of two dimensional (2D) crystals are crucial in emerging materials for nanoelectronics. A previously unexplored two-dimensional material, monolayer TeO2, is proposed to have high stability, a wide direct gap and high carrier mobility, based on first-principles calculations. Our results show that 2D TeO2 is both thermally and dynamically stable. In addition, it is easily exfoliated from its bulk counterpart, a natural layered mineral tellurite. Importantly, 2D TeO2 always exhibits a direct bandgap when thinning from bulk (3.32 eV) to monolayer (3.70 eV), an energy range not covered by previously reported 2D materials. Furthermore, monolayer TeO2 is exceptional in high transport anisotropy, possessing not only high electron mobility (of the order of 1000 cm2 V-1 s-1) but also exceptionally high hole mobility (up to 9100 cm2 V-1 s-1). All these findings make 2D TeO2 a promising candidate for both power electronics and short-wavelength optoelectronic applications.

Ceramic oxide photocatalysts have become significant materials for green energy production. This work presents the formation of various silver/silver oxide (Ag/Ag2O)-supported sol-gel synthesized tellurium dioxide (TeO2) nanojunction networks. The produced heterojunction photocatalysts were considered by different tools and demonstrated a photoactivity enhancement by introducing Ag/Ag2O at lower amounts (0.5–2.0 wt. %) without changing the surface texture or crystalline structure of TeO2. The decoration and existence of Ag/Ag2O were confirmed by high-resolution transmission electron microscopy and X-ray photoelectron spectroscopy. The 1.5 wt. % Ag/Ag2O-TeO2 demonstrated a broader visible-light response edged at 571 nm with a minimum bandgap energy of 2.18 eV compared to pristine TeO2 (543 nm and 2.38 eV, respectively). In addition, the formed heterojunctions were tested for hydrogen (H2) production from water in the presence of 10% glycerol and hexchloroplatinic acid as hole scavenger and cocatalyst, respectively. The 1.5 wt. % Ag/Ag2O-TeO2 demonstrated a promoted H2 production of 288.9 µmol g−1h−1, which is > 13-fold higher than the pristine TeO2 with admirable stability for five cycles. This improved H2 production using the novel Ag/Ag2O-TeO2 heterojunction is explained by the efficient light-harvesting, effective separation of the photogenerated charges within the nanojunction interface, and the synergistic effects of Ag existence and Pt deposition.

Elemental tellurium and tellurium dioxide are related to the hydrometallurgy of precious metal tellurides in two ways: (1) both species are products of precious metals tellurides cyanidation; and (2) tellurium dioxide is a by-product of the roasting of tellurides to produce metallic gold/silver prior to cyanidation. An investigation to elucidate the dissolution behavior of elemental tellurium and tellurium dioxide at 1250 mg/L CN−, pH 10.9, and 25 °C was carried out. For this purpose, batch test, thermodynamic simulation, and voltametric techniques were employed. The results showed that 8% of elemental tellurium was dissolved due to the inability of dissolved atmospheric oxygen to oxidize it. However, according to the potential-pH diagram, tellurium dissolution should continue to produce TeO2(OH)22−. Cyclic voltammetry for tellurium showed an oxidation pathway to form TeO32− and TeO42− at 240 and 982 mV, although an oxidation process indicating the slight dissolution of elemental tellurium was observed at −75 mV. Tellurium dissolution form tellurium dioxide reached 82% but it could be enhanced by increasing the pH beyond 11.5. The tellurium dioxide hydrolysis in alkaline media produced TeO2(OH)22− but the pH of the system tends to decrease; if pH in not adjusted, H2TeO3 will form, hindering the tellurium dissolution.

We report on the in situ synthesis through sol-gel processing of a tellurium dioxide (TeO2)–cellulose–polyvinyl alcohol (PVA) hybrid composite. The cellulose–PVA hybrid composite was synthesized through chemical graft in the presence of aqueous sodium hydroxide. Field emission scanning electron microscopy, SEM-EDX, high-resolution transition microscopy (FE-TEM) revealed that polycrystalline nanorods were uniformly distributed with sizes of 20 nm in the cotton cellulose–PVA–TeO2 hybrid nanocomposite. The average size of TeO2 crystallite was calculated to be 0.292 nm, as shown in the FE-TEM, SAED, and X-ray diffraction analysis. Furthermore, the hybrid nanocomposites were studied for their antimicrobial activity against Bacillus cereus and Escherichia coli strains, which was inhibited at a size of 10–12 mm after 24 h of incubation.

Surface functionalization is an effective approach for improving the gas-sensing capabilities of one-dimensional (1D) metal oxides. In this work, tellurium dioxide nanoparticles–decorated tungsten oxide nanorods (TeO2 NPs@W18O49 nanorods) were prepared via a facile two-step process, i.e. solvothermal synthesis of W18O49 nanorods followed by hydrolysis deposition of TeO2 NPs, for gas-sensing applications. In the TeO2 decoration process, sodium dodecyl benzene sulfonic acid was introduced as surfactant to assure formation and attachment of highly discrete, tiny TeO2 NPs on whole surface of nanorods. The microstructures of the decorated nanorods were characterized, and the effect of TeO2 decoration on the gas-sensing characteristics of W18O49 nanorods was investigated. It is found that TeO2 decoration reduces the optimal operating temperature of W18O49 nanorods-based sensor from 200 to 150 °C. The W18O49 nanorods decorated with discrete TeO2 NPs display about four-fold enhancement in gas response to 0.1–1 ppm NO2 at 150 °C compared to pure W18O49 nanorods. The underlying mechanism for the enhanced response of the decorated sensor was demonstrated based on an electronic sensitization-related conductance effect model.

Solvothermal synthesis and optimization of pure Bismuth telluride (Bi 2 Te 3 ) hexagonal nanoplatelets was carried out from Bismuth Oxide (Bi 2 O 3 ) and Tellurium dioxide (TeO 2 ). XRD measurements revealed a sensitive change in crystallization behaviour in correlation with variation in Te/Bi stoichiometry identified through the exchange in intensities between (10 10 ) and (110) peaks. Further, Energy Dispersive X-ray (EDAX) analysis revealed the variation in Te/Bi ratio with respect to autoclave temperature. Field emission scanning electron Microscope (FESEM) and the high resolution transmission electron Microscope (HRTEM) studies show the complete growth of hexagonal nanoplatelets at 200 °C. Confocal Micro-Raman measurements revealed the occurrence of symmetry breaking in the synthesized hexagonal nanoplatelets. The electrical conductivity and the activation energy were recorded as 6.01×10 − 3 S/m and 0.042 eV respectively. Highest maximum absolute value of Seebeck coefficient of –355 μV/K was obtained for the hexagonal nanoplatelets.

Simultaneous measurement of phonon and light signatures is an effective way to reduce the backgrounds and increase the sensitivity of CUPID, a next-generation bolometric neutrinoless double-beta decay ($0\nu\beta\beta$) experiment. Light emission in tellurium dioxide (TeO$_2$) crystals, one of the candidate materials for CUPID, is dominated by faint Cherenkov radiation, and the high refractive index of TeO$_2$ complicates light collection. Positive identification of $0\nu\beta\beta$ events therefore requires high-sensitivity light detectors and careful optimization of light transport. A detailed microphysical understanding of the optical properties of TeO$_2$ crystals is essential for such optimization. We present a set of quantitative measurements of light production and transport in a cubic TeO$_2$ crystal, verified with a complete optical model and calibrated against a UVT acrylic standard. We measure the optical surface properties of the crystal, and set stringent limits on the amount of room-temperature scintillation in TeO$_2$ for $\beta$ and $\alpha$ particles of 5.3 and 8 photons / MeV, respectively, at 90% confidence. The techniques described here can be used to optimize and verify the particle identification capabilities of CUPID., Comment: 14 pages; 9 figures

Influence of different oxide overlayers on the performance of phase modulated optical fiber sensor coated with graphene is reported. The simulation model is constructed according to the the transmission matrix theory. In this work, we improve the phase sensitivity of the sensor by adding different oxides coatings include magnesium oxide (MgO), aluminum oxide (Al 2 O 3 ), lutetium oxide (Lu 2 O 3 ), scandium oxide (Sc 2 O 3 ) and tellurium dioxide (TeO2) on the surface of monolayer graphene. The phase sensitivity of the sensor is optimized by the type and thickness of oxide coating. The phase sensitivity of the sensor with 35 nm TeO 2 coating on the surface of monolayer graphene achieved 1.3467 × 105deg/RIU.

Effect of media temperature on the acousto-optic (AO) phase matching condition is examined both theoretically and experimentally by an example of tellurium dioxide crystal with 10.5° cut-angle. It is shown that variation of the AO crystal temperature changes the acoustic wave velocity that is involved into the AO interaction and shifts the AO diffraction phase matching frequency. We introduced the temperature coefficient of AO phase matching frequency shift. The measurements of frequency shift magnitude were carried out at the optical wavelengths from 0.44 μm to 1.52 μm. It is shown that the shift coefficient decreases with the optical wavelength. A method is proposed that makes it possible to calculate the temperature shift coefficients for AO devices in a wide range of optical wavelengths. The coefficients obtained by the proposed method are in good agreement with the experimental data. Ultrasound attenuation is also examined experimentally in the given AO cell in a wide range of acoustic wave frequencies.

Crystals of the 422 symmetry class exhibit interesting piezoelectric behavior, as their piezoelectric tensor has only a single non-zero coefficient, d123 = d14: such unique behavior has the potential to enable novel gyroscopic sensors and high-precision torsional MEMS actuators. Although alpha-phase tellurium dioxide (paratellurite, alpha-TeO2) is one of the few materials belonging to this symmetry class, this material has been primarily studied for its interesting optical properties. Indeed, a large uncertainty in the piezoelectric coefficient of paratellurite exists, with d123 measurements on single crystals ranging from 8.13 pC/N to 14.58 pC/N; this large uncertainty results from the difficulty in using conventional piezoelectric characterization techniques on paratellurite, and impedes adoption of this extraordinary material. The present study characterizes the piezoelectric behavior of this interesting material using two independent techniques, (1) a three dimensional laser Doppler interferometer system, and (2) electrochemical impedance spectroscopy (EIS). The experimental results are analyzed using numerical simulations for dynamic excitation conditions over a frequency range of 20 Hz to 200 kHz.

Production of iodine-131 by neutron activation of tellurium in tellurium dioxide (TeO 2 ) material requires a target that meets the safety requirements. In a radiopharmaceutical production unit, a new lid for a can was designed, which permits tight sealing of the target by using tungsten inert gas welding. The leakage rate of all prepared targets was assessed using a helium mass spectrometer. The accepted leakage rate is ≤ 10 −4 mbr.L/s, according to the approved safety report related to iodine-131 production in the TRIGA Mark II research reactor (TRIGA: Training, Research, Isotopes, General Atomics). To confirm the resistance of the new design to the irradiation conditions in the TRIGA Mark II research reactor's central thimble, a study of heat effect on the sealed targets for 7 hours in an oven was conducted and the leakage rates were evaluated. The results show that the tightness of the targets is ensured up to 600°C with the appearance of deformations on lids beyond 450°C. The study of heat transfer through the target was conducted by adopting a one-dimensional approximation, under consideration of the three transfer modes—convection, conduction, and radiation. The quantities of heat generated by gamma and neutron heating were calculated by a validated computational model for the neutronic simulation of the TRIGA Mark II research reactor using the Monte Carlo N-Particle transport code. Using the heat transfer equations according to the three modes of heat transfer, the thermal study of I-131 production by irradiation of the target in the central thimble showed that the temperatures of materials do not exceed the corresponding melting points. To validate this new design, several targets have been irradiated in the central thimble according to a preplanned irradiation program, going from 4 hours of irradiation at a power level of 0.5 MW up to 35 hours (7 h/d for 5 days a week) at 1.5 MW. The results show that the irradiated targets are tight because no iodine-131 was released in the atmosphere of the reactor building and in the reactor cooling water of the primary circuit.

Structural evaluation on 70TeO2–20SeO2–10R2O (R = potassium (K), sodium (Na) and lithium (Li)) ternary glass system has been studied using infrared (IR) and Raman techniques. Main building units of both glass formers (tellurium dioxide (TeO2) and selenium dioxide (SeO2)) play a vital role in the construction of amorphous network. According to the IR and Raman data, it is clear that the structural building units appearing in the glass system are selenium trioxide (SeO3), lithium tetraoxide (LiO4), potassium tetraoxide (KO4), sodium oxide (NaO), tellurium trioxide (TeO3) and tellurium tetraoxide (TeO4). Adding alkali oxide to tellurium dioxide leads to a gradual reduction of the tellurium coordination from TeO4 → TeO3+1 → TeO3; in addition to this, selenium dioxide also plays vital role in forming the glass structure. Mixing potassium, sodium and lithium to the selenium–tellurite glass system results in cleavage of Te–O–Te and Se–O–Se linkages by formation of TeO3 − and SeO3 − terminal groups. Among these, tellurium trioxide units are the dominant basic structural entities. Glass structural fragments are associated with the type of alkali oxide (potassium, sodium and lithium) and sterical hindrance of heavy alkali oxide produces distortions of the glassy network and reduces its rigidity.

A facile and economical one-pot strategy has been developed for the synthesis of water-solute CdTe and CdTe/ZnS core/shell quantum dots (QDs) using tellurium dioxide (TeO2) as a tellurium precursor and thioglycolic acid (TGA) as stabilizer without any pre-treatment and inert atmosphere protection. As-synthesized QDs were characterized by transmission electron microscopy (TEM), high-resolution transmission electron microscopy (HRTEM), electron diffraction spectroscopy (EDS), X-ray powder diffraction (XRD), UV-vis and photoluminescence (PL). The spherical particles were uniformly distributed with the average diameters of 3.2 nm (CdTe QDs) and -5 nm (CdTe/ZnS QDs). By altering the reaction conditions, the emission wavelengths of the CdTe core QDs and CdTe/ZnS core/shell QDs could be tuned from 508 to 574 nm and 526 to 600 nm with narrow full widths at half maximum (FWHM) of 33 to 58 nm, respectively. Meanwhile, on the optimum condition, the luminescence efficiency of CdTe/ZnS QDs can achieve to 74%, which was higher than that of CdTe core QDs (24%).

We have investigated the coprecipitation of tellurium(IV), tungsten(VI), and lanthanum(III) hydroxides through the addition of aqueous ammonia to a mixture of tellurium dioxide, lanthanum oxide, and tungstic acid solutions in hydrochloric acid. The effects of initial solution composition and precipitation pH on the composition of the precipitate have been assessed. It has been shown that the composition of the precipitate is essentially identical to that of the starting solution if the relative contents of lanthanum and tungsten in the mixture are within 20 mol % and precipitation is ceased at pH 7.

Bismuth telluride (Bi2Te3) is the currently best performing thermoelectric (TE) material in commercial TE devices for refrigeration and waste heat recovery up to 200 °C. Up to 800 μm thick, compact, uniform and stoichiometric Bi2Te3 films were synthesized by pulsed electrodeposition from 2 M nitric acid baths containing bismuth and tellurium dioxide on 1 cm2 nickel (Ni) substrates at average film growth rates of ~50 μm/h. Pre-treatment of the Ni substrate was found to significantly enhance the adhesion of Bi2Te3 material onto Ni while pulsed electrodeposition was used to increase the compactness of the material. To maintain a homogeneous composition across the thickness of the films, a sacrificial Bi2Te3 anode was employed. All deposits produced were n-type with a Seebeck coefficient of up to −80 μV/K and an electrical conductivity of ~330 S/cm at room temperature. Keywords: Bismuth telluride, Electrodeposition, Thick films

Epoxy nanocomposites were synthesized in the presence of hydroxyapatite with the aid of an ultrasonicator. In general, as the amount of hydroxyapatite increased from 0wt% to 10wt%, the mechanical properties of the hydroxyapatite-containing nanocomposite were enhanced. The mechanical properties of the nanocomposite were significantly enhanced by the simple addition of 10 wt% of hydroxyapatite. Specifically, the storage modulus of the 10 wt% hydroxyapatite-containing nanocompsote was 3.2GPa, which is 46% higher compared to that of the pristine epoxy nanocomposite. The glass transition temperature of hydroxyapatite-containing nanocomposites generally decreased by few degrees in Celsius. To investigate the effect of additives on the mechanical properties of the epoxy-based nanocomposite, nanocomposites were synthesized using both montmorillonite and tellurium dioxide instead of hydroxyapatite. Intrestingly, both additive-based nanocomposite materials resulted in an increase in the storage modulus while the glass transition temperature decreased. These results demonstrate that the addition of few wt% of all three additives (hydroxyapatite, montmorillonite, and tellurium dioxide) can enhance the mechanical properties of epoxy-based nanocomposites.

In this experimental work, the oxygen concentration electrochemical galvanic cell of the type (−) Pt|Pt(s), PtTe(s), TeO2(s,l)|YSZ|O2(g)|Pt (+) was applied to determine the thermodynamic properties of intermetallic platinum monotelluride PtTe. Yttria-stabilized zirconia solid electrolyte was utilized as a fast oxygen ion conductor. The repeatability of the experimental results was ensured by conducting three identical runs in stepwise heating and cooling cycles. The standard Gibbs energy of formation of PtTe was determined for the first time in the temperature range from (890 to 998) K to be: Δ f G ° / ( kJ · mol - 1 ) ± 0.49 = - 73.54 + 28.57 · 10 - 3 · T / K. The enthalpy of fusion and melting temperature of tellurium dioxide TeO2 were redetermined.

The CUORE-0 experiment searches for neutrinoless double beta decay in $$^{130}$$ Te. It consists of an array of 52 tellurium dioxide crystals, operated as bolometers at a temperature of 10 mK, with a total mass of about 39 kg of TeO $$_2$$ . CUORE-0 has been built to test the performance of the upcoming CUORE experiment and represents the largest $$^{130}$$ Te bolometric setup currently in operation. This experiment has been running in the Gran Sasso National Laboratory, Italy, since March 2013. We report the results of a search for neutrinoless double beta decay in 9.8 kg years $$^{130}$$ Te exposure, which allowed us to set the most stringent limit to date on this half-life. The performance of the detector in terms of background rate and energy resolution are also reported.

Herein, tellurium (Te), tellurium dioxide (TeO2) and Te/TeO2 nanostructures were successfully synthesized via a one-pot hydrothermal route using TeCl4 as a tellurium source. The obtained products were characterized by XRD, SEM, TEM, FT-IR, EDS, and DRS. The effects of different parameters such as temperature, time, surfactant, solvent etc. on the morphology, particle size and product type of the as-synthesized nanostructures were investigated. Based on the XRD results, it was found that the production of Te increased by increasing the reaction temperature. Also, pure Te nanorods were obtained in the presence of ethylene glycol, and when using ammonia pure TeO2 microstructures were formed. Providing favorable conditions for the formation of pure Te and pure TeO2 results in the self-assembly of nanoparticles to form 1-D structures and 3-D nanostructures, respectively, but providing conditions for the formation of a mixture of Te/TeO2 leads to the formation of 0-D nanostructures. These results are significant because the obtained mixture can easily transform to 0-D nanostructures of TeO2 and Te.

Thin films of CdTe semiconductor were electrochemically deposited using two-electrode and three-electrode configurations in potentiostatic mode for comparison. Cadmium sulphate and tellurium dioxide were used as cadmium and tellurium sources respectively. The layers obtained using both configurations exhibit similar structural, optical and electrical properties with no specific dependence on any particular electrode configuration used. These results indicate that electrochemical deposition (electrodeposition) of CdTe, and semiconductors in general, can equally be carried out using two-electrode system as well as the conventional three-electrode system without compromising the essential qualities of the materials produced. The results also highlight the advantages of the two-electrode configuration in process simplification, cost reduction and removal of a possible impurity source in the growth system especially as the reference electrode ages.\ud \ud Keywords: Electrochemical deposition; two-electrode system; three-electrode system; CdTe; thin-films; solar cells.

The results from in situ and post-exposure studies of the effect an electron beam has on the optical characteristics of a tellurium dioxide single crystal are presented. The acoustooptical material is irradiated with electrons having an energy of 5 MeV. The transmission and absorption spectra of the paratellurite crystal are measured at different absorbed radiation doses. The dose dependence of the intensity of light with a wavelength of 357 nm transmitted through the crystal is determined.

In order to satisfy the performance requirements of the pyrotechnic ignition composition of a space mission under an extreme thermal environment, it is necessary to analyze and verify the thermal stability of magnesium/tellurium dioxide (Mg/TeO2) ignition composition at a temperature of 180 &deg, C. The thermal stability of the ignition composition of Mg/TeO2 and its components after exposure to 180 &deg, C for 2&ndash, 10 days was studied by means of apparent morphology analysis, differential scanning calorimetry (DSC), X-ray diffraction (XRD), content change analysis, and the P-t curve test. The results showed that after exposure to 180 &deg, 10 days, no obvious changes, such as ruptures, expansion, or shrinkage, were found by optical microscope, and no changes in morphology and surface details were found by scanning electron microscope (SEM). XRD showed that no other new substance was found in the mixture except magnesium hydroxide (Mg (OH)2). DSC showed that the main reaction peak temperature of the ignition composition of Mg/TeO2 was after 500 &deg, C and that no endothermic/exothermic reaction occurred before 380 &deg, C. The exothermic pre-reaction took place at 381 &deg, C to 470 &deg, C, the weight loss ratio was within 0.71%, the content of the magnesium component varied from 0.49% to 0.90%, the peak pressure attenuation of the ignition composition of 360-mesh Mg/TeO2 was 8.07%, and the pressure rise time was basically unchanged. The results showed that the ignition composition of Mg/TeO2 had good thermal stability after exposure to 180 &deg, C temperatures.