Increase In Annealing Duration Research Articles

Improving the thermoelectric properties of zinc tin oxide thin films by varying post growth annealing duration

In this research work, we have successfully improved the thermoelectric properties of Zinc tin oxide thin films by controlling the post annealing duration. Initially, zinc tin oxide thin films were grown by direct evaporation of zinc and tin metal powder using the thermal evaporation method. After deposition, post growth annealing of the grown thin films was performed at 500 °C for different annealing durations (0.5, 1, 1.5 & 2 h). XRD data show the structural transformation from amorphous to mixed phases of Zn2SnO4, ZnSnO3, ZnO, and SnO2 with the increase in post-growth annealing duration. While the sample annealed for 2 h represent only two phases of ZnO and ZnSnO3. UV–vis data shows the decrease in band gap value from 3.8 to 3.61 eV with the increase in annealing duration. Seebeck data suggested the improvement in the Seebeck coefficient value from 24 to 104 μV/°C with the increase in annealing time duration while the electrical conductivity value was also improved from 34 to 63 S/cm. This increase in Seebeck coefficient and electrical conductivity was associated with the phase transformation into ZnSnO3 by suppression of un-wanted secondary phases leads to a high power factor up to 3.1 × 10−4 Wm−1K−2. In addition, we have also performed Raman and SEM as supplementary measurements to support our purposed argument.

A Correlative Study of Film Lifetime, Hydrogen Content, and Surface Passivation Quality of Amorphous Silicon Films on Silicon Wafers

We examine correlations between the recombination lifetime and hydrogen content of hydrogenated amorphous silicon films (a-Si:H) and the surface passivation afforded by such films when deposited on crystalline silicon wafers, during annealing at 350–500 °C. Our results show that, as the annealing duration increases, both the a-Si:H recombination lifetime and the surface recombination velocity evolve at a similar rate to the hydrogen concentration. This suggests that the loss of hydrogen during annealing is the direct cause of the reduction in the a-Si:H film lifetime, and that the loss of hydrogen occurs both at the a-Si:H/c-Si interface as well as in the bulk of a-Si:H film. We calculated the activation energy of the surface depassivation reaction during annealing to be 0.62 ± 0.1 eV, which suggests that the depassivation reaction is limited by the migration of hydrogen within the film, without significant hydrogen trapping. Secondary-ion mass spectrometry further demonstrates the loss of hydrogen across the film thickness during annealing.

Annealing duration influence on dip-coated CZTS thin films properties obtained by sol-gel method

The effect of annealing duration on structural and optical properties of dip-coated crystalline CZTS thin films was studied. The obtained samples were investigated by several techniques such as XRD, Raman spectroscopy, SEM, UV–vis spectroscopy and Photoluminescence. Being confirmed by Raman spectroscopy, XRD analysis reveals the formation of kesterite tetragonal phase with preferential orientation along (112) direction. The grain size tends to increase as the annealing duration increases, a result confirmed by SEM. The last shows smooth, uniform, homogeneous and densely packed grains. Optical measurement analysis reveals that layers have relatively high absorption coefficient in the visible spectrum with a band gap reduction of 1.62−1.50 eV which is quite close to the optimum value for a solar cell. The photoluminescence distinguishes broad bands that have maximums of intensity limited between 1.50 and 1.62 eV, corresponding to the optical band gap of the CZTS.

Structural, optical and waveguiding properties improvement of SiO2/TiO2 Bragg reflectors processed by the sol–gel method under the effect of Ni-doped TiO2 and annealing duration

We investigated the nickel doped TiO2 layer and annealing duration effects on SiO2/TiO2 Bragg reflectors. The films crystallize in pure anatase phase whatever is the Ni content and the annealing duration. In UV–vis-NIR analyses, variations of width, position and transmission coefficient of the stop-band were observed. The PL spectra red-shifted when the Ni content and annealing duration increased. As the annealing duration increases, an additional sharp emission peak appears around 867nm, indicating a reduced number of defects. As Ni content increased, the M-lines spectroscopy shows two transverse electric polarization guided modes TE0 and TE1, which indicates a decreased refractive index and an increased film thickness.

An investigation to the microstructural evolution of Fe–29Mn–5Al dual-phase twinning-induced plasticity steel through annealing

The potential effects of twinning induced plasticity have been taken into consideration to further improve the mechanical properties of advanced high-strength steels. Accordingly the high-Mn twinning-induced plasticity (TWIP) steels with austenite–ferrite dual-phase microstructure have been developed. In the present study, the influence of cold rolling and post-annealing treatments on the microstructural evolution and mechanical behavior of a group of dual-phase TWIP steel as a function of annealing time have been investigated. The mechanical behavior of processed materials has been examined through applying a set of low strain rate (0.001 s −1) compression tests at room temperature. The austenite recrystallization characteristics during various annealing conditions are explained through proper microstructural examinations. The results indicate that as the recrystallization proceeds with annealing time the related yield stress deceases. The rapid drop of yield stress in short annealing periods is related to the onset of recrystallization. The yield stress variation diminishes as the annealing duration increases. This is attributed to the formation of austenite side-plates which may balance the softening effects of restoration processes.

Domain wall pinning in sputtered soft amorphous magnetic thin films

Domain wall pinning in sputtered soft amorphous thin films has been observed similar to that seen in rapidly quenched amorphous ribbon. The pinning is induced by annealing samples in their nonsaturated state. The easy-axis hysteresis loop of such a sample shows a characteristic stop in the change of magnetization at a nonsaturated magnetization value for both an increase and decrease of applied field, corresponding to the field value when the domain walls are pinned. An abrupt increase of magnetization is observed when the pinning is overcome by a large enough applied field, called wall pinning force (Hp). Sputtered amorphous Fe5.85Co72.15Mo2B15Si5 thin films with coercivity of about 0.06 Oe and thickness of about 6500 Å gave a wall pinning force as high as 0.6 Oe. The general mechanism of the wall pinning was confirmed by domain viewing. For different annealing temperatures, the wall pinning force increases as the annealing duration increases and approaches a maximum value. A linear relation between the maximum value of wall pinning force and the field-induced magnetic anisotropy field was obtained.