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The infrared optical transmission spectra of 3 and 5 wt.% of carbon nanotube (CNT)-containing Se85Te10Ag5 glassy composites were recorded in the mid-IR region from 4000 to 400 cm−1 using Fourier transform infrared spectroscopy (FTIR). The FTIR spectra manifested functional groups interacting the CNT surface and the Se85Te10Ag5 glassy matrix. Photoluminescence (PL) spectra of the CNT-containing Se85Te10Ag5 glassy composites exhibited PL emission peaks centred within the range 715–725 nm. The optical absorption spectra differed between pure Se85Te10Ag5 glass and the CNT-containing Se85Te10Ag5 glassy composites. The electrical conductivity of CNT-containing Se85Te10Ag5 glassy composites was enhanced by four orders of magnitude with the CNT additive. This can be attributed to the formation of many conductive paths through the CNT–CNT internanotube percolation network.

Herein, we report the synthesis of highly yielded bismuth-telluride (Bi2Te3) nanoparticles at 50 °C by direct wet chemical route in which the bismuth and tellurium precursors have been dissolved in deionised water, ethylene glycol and hydrazine hydrate. This method is very facile, inexpensive and less hazardous and ensures almost complete yield of the precursors. The powder product was well characterised by powder X-ray diffraction, UV-Vis spectroscopy, Fourier transform infrared spectroscopy, energy dispersive X-ray diffraction, transmission electron microscopy and scanning electron microscopy. It is investigated that the synthesised powder has a rhombohedral structure of Bi2Te3 with average diameters of the particles about 35 nm. Thus, the synthesis process has been modified to design nanostructures of thermoelectric materials with related crystal structures.

The crystallisation kinetics of bulk Se75Te15− x Cd10In x (x = 0, 5, 10 and 15) multi-component chalcogenide glasses have been studied using differential scanning calorimetry with different heating rates (5, 10, 15 and 20 K/min) under non-isothermal conditions. Various kinetic parameters of crystallisation, such as the onset crystallisation temperature, peak crystallisation temperature, activation energy for crystallisation and order parameter have been determined. The composition dependence of these parameters is explained in terms of topological models based on constraint theory.

We report the measurements on Se93− x Zn2Te5In x (0 ≤ x ≤ 10) chalcogenide glasses using differential scanning calorimetry. The thermal stability and glass forming ability of these glasses are studied by different criteria. The composition dependence of the various kinetic parameters of crystallization is discussed.

In this paper, we report on the non-isothermal crystallization kinetics of Se98 −x Zn2In x (0 ≤ x ≥ 10) chalcogenide glasses. The onset crystallization activation energy E c, peak crystallization activation energy E p and overall crystallization activation energy E have been determined by different approaches. The values of E c, E p and E have minima at a composition corresponding to 6 at% In. However the stability factor S and the crystallization rate constant stability factor K have a maximum and a minimum, respectively, at in the same composition. The nucleation and growth order parameter n, and the dimension order parameter m, are also determined and discussed for the present glasses.

The UV–VIS absorption spectra of thin film of Se98−x Zn2In x (x = 0, 2, 4, 6 and 10) chalcogenide glasses were measured in the wavelength range of 200–1100 nm by using spectrophotometer. It is observed from UV–VIS absorption measurements that the optical energy gap (E g ) decreases with In content and it found a minimum for the Se92Zn2In6 system. The refractive index (n), extinction coefficient (k), real dielectric constant (ϵ′) imaginary dielectric constant (ϵ″), absorption coefficient (α) are evaluated maximum for the Se92Zn2In6 composition. However, FTIR spectra were recorded in the wavenumber range 4000–400 cm−1. The FTIR recorded spectrum was shown to be a broad spectrum with increasing transmission in the MID (6–25 m) infrared region. The MID-IR spectrum transmittance percentage was also found to be considerably high for the Se92Zn2In6 system.

Calorimetric measurements have been performed in glassy Se75Te15M10 (M=Sb, Sn) alloys to study the effect of Sb and Sn additives on the kinetics of glass transition and crystallisation in glassy Se85Te15 alloy. Activation energy of glass transition (E g) and the activation energy of crystallisation (E c) have been determined using different non-isothermal methods. An excellent agreement is observed in the values of E c and E g for all the non-isothermal methods used in the present study. The composition dependence of the activation energies of glass transition and crystallisation processes shows that the value of E g is higher in case of Sn additive while the value of E c is higher in case of Sb additive. The results are explained in terms of Pauling's concept of average heat of atomisation and mean atomic weights of ternary alloys, respectively.

The time-dependent dielectric breakdown of thermally grown SiO2 films in M-O-S structures was studied using standard, PSG and HCl oxides. The time to breakdown was found to decrease exponentially with the increase of applied electric fields. The effect of mobile ion concentration and temperature on time to breakdown was also studied. Peek's law behaviour (Eαt-1/4) was verified for the contaminated samples. Contrary to previous reported results, the devices having comparatively low contamination level have been observed to obey Peek's law. The discrepancy in the result is attributed to the presence of comparatively large quantities of defects in our devices.