GaSe4 films were prepared using thermal evaporation technique onto glass and Si substrates. GaSe4 in both ingot and thin films was studied by hot probe procedure indicated n-type semiconductor. The conductivity activation energy (ΔE) decreased from 0.414 to 0.365 eV with the increase in film thickness from 90 to 500 nm. Investigation of the heterojunction n-GaSe4/p-Si by using characteristics indicated good rectification with rectification ratio of 48 at room temperature and at V = ±1.6 V. The ideality factor decreased from 2.2 to 2.13 while the reverse saturation current decreased from 8.3 × 10−7 A to 3.27 × 10−7 A by the temperature rise from 310 to 363 K. For lower and higher values of applied voltage, Pool-Frenkel and Schottky coefficients were 2.2 × 10−5 and 0.7 × 10−5 eV m−1/2, beside that, Schottky barrier height was found to be 0.4 eV. The thermionic emission mechanism occurs in the low forward voltage range but in the high forward region, the space-charge-limited current (SCLC) controlled by a single trap level is the dominant mechanism. In the reverse direction the Poole-Frenkel mechanism is the operating mechanism. Analysis of C-V characteristics of Au/n-GaSe4/p-Si/Al heterojunction gives the values of effective density of states (N) of 2.4 × 1034 cm−3 and the built-in voltage (Vb) of the junction is 0.78 V.

In the present paper, we have theoretically predicated some significant physical parameters, i.e., coordination number, constraints, density, molar volume, cohesive energy, heat of atomization, etc., for glassy Se80Te20 and glassy Se80Te10M10 (M = Cd, In, Sb) alloys. A theoretical study of the glassy Se80Te20 and glassy Se80Te10M10 (M = Cd, In, Sb) alloys reveals that there is a significant change in the structural environment of the system due to rigidity percolation.

The electronic charge transport in active layer of organic thin-film transistor (OTFT) based on conductor polythiophene (sexithiophene (6T) and octithiophene (8T)) was studied. A mathematical model is presented based on the variable range hopping (VRH) transport theory. Using the VRH model the expression of source-drain current is established for two regimes: linear regime for drain bias VD = −2 V and saturation regime for VD = −30 V at low temperature and at room temperature. All electrical key parameters of OTFTs based on polythiophene have been extracted. A good agreement between theoretical model and experimental measurement of electrical characteristics is obtained for both temperature ranges: low temperature and room temperature.

We propose the spot-size effect in laser-induced damage to optical thin films as a method to investigate the defect removal model which is one of the laser conditioning mechanisms, and the theoretical and experimental studies are presented. A standard deviation σ2 is set up for fitting the damage thresholds which are obtained by multi-spot size test. The laser conditioning effect on ZrO2/SiO2 multilayer high reflective films is analyzed through this application. It is found that the mean distance of two initiating defects is increased by laser conditioning, which means that the defect density is decreased. Thus, the initiating defects are removed partially by laser conditioning. Furthermore, the intrinsic damage threshold of the film is little affected through the laser conditioning process.

Titanium nitride thin films have been grown on Si substrates by using DC reactive magnetron sputtering from a titanium target at different DC power (100–400 W). The different plasma parameters such as plasma potential, floating potential, electron temperature, electron density and ion density have been measured using a Langmuir probe. The electron energy distribution function (EEDF) has been evaluated from the second derivative of I-V plot of the Langmuir probe data and has shown to be bi-Maxwellian. The correlations between measured plasma parameters and the properties of TiN films deposited at the same operating conditions have been studied. It has been observed that the hardness decreases and the resistivity increases in films deposited at higher DC power. This is attributed to the growth of Ti2N phase at higher powers. The mechanical properties of the films have also been studied.

The effect of dc magnetic field on the capacitance, impedance and resistance of Dy2.8Sr0.2Fe5O12 (DySrIG) prepared using the citrate-nitrate auto-combustion method was studied at room temperature. The measurements were carried out in two ways; the first one in which the dc magnetic field and the ac electric field are parallel (//) to each other and the second one in which the magnetic field and ac electric fields are perpendicular (⊥) to each other. The magnetoimpedance of Dy2.8Sr0.2Fe5O12 increases by about 80% in the (⊥) case (at 1650 Oe and 450 kHz) with respect to its values at zero magnetic field. The results of the study encourage the use of this garnet nanomaterial in magnetic sensors, in new devices including tunable filter and spintronic applications.

This paper presents a novel preparation of copper (Cu) deposited titanium dioxide (TiO2) nanotubes in photoelectrochemical systems. The main target was improving TiO2 applications in the areas of energy conversion under visible light. Herein, we investigated different amount of Cu deposited TiO2 nanotubes using thermal evaporation technique. Based on the results, small amount of Cu (1.09 wt.%) showed the improvement in photoelectrochemical (PEC) response under visible light. Optimum amount of Cu deposited on TiO2 nanotubes will inhibit recombination rate of photogenerated charge carriers and improve the charge separation and transfer under visible light illumination. However, the excess amount of Cu deposited on TiO2 nanotubes will impede the photocurrent to flow and resulted in lower photoconversion efficiency. The reason may be attributed to the formation of composite structure on TiO2 nanotubes that serve as defects in the Cu/TiO2 interface by the lattice mismatch that will serve as recombination site for the charge carriers.

This paper presents a detailed investigation on the effect of heat-treatment process on the highly ordered titanium dioxide (TiO2) nanotube arrays in connection with the photoelectrochemical (PEC) response and hydrogen evolution rate. TiO2 nanotube arrays have been systematically heat-treated to control the transformation of as-anodized TiO2 amorphous structure to crystalline anatase and rutile phases. In this study, single crystalline TiO2 anatase phase exhibited a higher PEC response and hydrogen evolution rate at 400 °C heat treatment. The photocurrent density increase was mainly attributed to the effective transport of photo-induced electrons within the single crystal anatase phase. However, polycrystalline anatase and rutile phases showed the fluctuation in lower photocurrent density upon heat treatment above 500 °C. The mobility of photo-induced electrons was obviously hindered due to the recombination losses in defect sites between the anatase and rutile phase.

The effect of argon concentration (10%–40%) on the surface properties of molybdenum is studied in nitrogen-argon mixture using 100 Hz pulsed dc glow discharge. The analysis is carried out by using X-ray diffractometer (XRD), scanning electron microscopy (SEM), atomic force microscopy (AFM) and Vickers microhardness tester to investigate surface properties of the nitrided samples. XRD results exhibit the formation of molybdenum nitrides. Crystallite size analysis and SEM morphology confirm the growth of nanostructured molybdenum nitride layers. Moreover, significant increase in surface hardness (by a factor of about two times) is found when the sample is treated for 30% argon in nitrogen-argon mixed plasma.