Effects Of Post-annealing Temperature Research Articles

Realization of CO2 gas sensors and broadband photodetectors using metal/high-k CeO2/p-Si heterojunction

Realization of high-k dielectric oxide material-based devices such as photodetectors (PDs)/gas sensors fabricated on silicon substrate seems to be the utmost promising as a cost-effective approach to use in next generation optoelectronic field. We have explored metal/CeO2/p-Si heterojunction to construct as a broadband (BB) PD and CO2 gas sensor device. The effect of post-annealing procedure on photodetection and CO2 gas sensing characteristics were correlated using AFM, XRD, XPS, Raman and UV–Vis studies. At 0 V bias, the fabricated as-deposited Au/CeO2/p-Si PD device exhibits outstanding performance with enhanced responsivity of 85 AW−1 (at 910 nm), detectivity of 1.36×1015 Jones (at 850 nm), EQE of 1.3×104 % (at 850 nm), faster rise and fall times of 124 ms and 107 ms (at 900 nm). On the other hand, the photodetection characteristic parameters were slightly deteriorated as a function of annealing with respect to the as-deposited device. One of the causes for this fact was attributed to the increase in rms surface roughness (AFM) and decrease in absorbance of CeO2 thin film (UV–Vis). Additionally, Ag/CeO2/p-Si heterojunction was studied as a CO2 gas sensor and evaluated response/recovery times as a function of CO2 gas concentration. Sensing responses of CeO2 as-deposited, CeO2-400, CeO2-500, CeO2-600 and CeO2-700 °C were around 58, 60, 62, 81 and 90 %, respectively, when exposed to 200 ppm of CO2. Thus, we validate that the prospect of integrating enhanced performance in BB PDs and CO2 gas sensors using metal/CeO2/p-Si heterojunction could serve as a basic building block in near future optoelectronic applications. Furthermore, the effect of post-annealing temperature on the morphological, structural, BB photodetection and CO2 gas sensing properties were discussed in detail.

Microstructure, dielectric, ferroelectric and piezoelectric properties of K0.45Na0.45Li0.1NbO3 lead-free ceramics prepared via cold sintering with post-annealing

Via the method of cold sintering with post-annealing, the lead-free ceramics [Formula: see text][Formula: see text][Formula: see text]NbO3 were prepared. The cold sintered pellet without post-annealing shows a relative density ([Formula: see text] of 77.9%, which is larger than [Formula: see text] of the green pellet via the conventional solid-state sintering (SSS) method ([Formula: see text]). The cold sintered pellets were post-annealed at temperatures between [Formula: see text]C and [Formula: see text]C. The effect of post-annealing temperatures on microstructure, dielectric, ferroelectric and piezoelectric properties of the ceramics was studied in detail. After being post-annealed, the relative densities and grain sizes of the ceramics were increased. The ceramics post-annealed at [Formula: see text]C show excellent dielectric, ferroelectric and piezoelectric properties. Compared to the conventional SSS method, the method of cold sintering with post-annealing is successful in preparing dense [Formula: see text][Formula: see text][Formula: see text]NbO3 lead-free ceramics in a wide temperature range and at relatively low temperatures.

A modified drop-casting technique for efficient lead-free, environment-friendly thin film CsBi3I10 perovskite solar cells

The efficiency of lead-based perovskite solar cell deteriorates due to their instability and toxicity which inhibits their commercial application. Both of these issues are resolved by substituting Bismuth in place of lead. In order to create environmentally friendly perovskite solar cells (PSCs), bismuth-based halide perovskite (CsBi3I10) is a promising absorber material. Bismuth-based CsBi3I10 perovskite films were fabricated using a modified drop-casting process at room temperature. With this technique, you can get a film with desirable characteristics including a smooth, uniform surface and no pinholes. A comprehensive analysis is carried out in this research article as a result of the fact that thermal annealing is the first step in the process of transforming the deposited solution into the perovskite material. Band gap tuning is achieved with the use of this heat treatment. As film that has been post-annealed at the low temperature of 60 °C is not only tuned in terms of conductivity with a low band gap of 1.78 eV, but it also has improved absorption. In contrast, hexagonal particles with a low absorbance and a greater band gap of 2.08 eV develop at higher post-annealing temperatures. Band gap is greater (2.21 eV) and nonhomogeneous layered structure is formed in the film that does not undergo any post annealing treatment. The effects of post-annealing temperature on morphological, structural, and optical properties are explored and connected with photovoltaic application requirements. Finally, the photovoltaic performance of PSCs based on CsBi3I10 without hole transport layer (HTL) is investigated quantitatively in this study.

Spin Hall magnetoresistance and the effect of post-annealing temperature in the MOD-grown HoIG

We present the fabrication of ultrathin Ho3Fe5O12 (HoIG) films on 111- oriented-Gd3Ga5O12 (GGG) via the metal-organic decomposition (MOD) method followed by a sequence annealing process. We characterized the crystal structure, surface morphology, and magnetic properties to study the effect of annealing temperature on the quality of MOD-grown HoIG films. For temperatures higher than 800 ⁰C, we observe the infiltration of Iron (Fe) from the HoIG film into the GGG substrate. In particular, the Fe-diffusion is significantly enhanced for a 1000 ⁰C-annealed sample of which crystal structure and magnetic properties are also affected. For temperatures lower than 800 ⁰C, on the other hand, the smooth surface and strong crystallinity cannot be guaranteed. This suggests that an annealing temperature of 800 ⁰C is the optimal condition for the MOD-grown HoIG film. The quality of the sample is further confirmed by measuring the spin Hall magnetoresistance (SMR) of HoIG/Pt, in which we found the unconventional angular dependence and comparable spin mixing conductance similar to the previous reports in other single crystalline IGs.

Impact of post-annealing temperature on optical and surface properties of tellurium doped ZnO nanocrystalline films

Investigated in this work is the effect of post-annealing temperature on ZnO nanocrystalline thin films doped with 5 at.% tellurium. The spin coating method was used to deposit films on the microscopic glass substrates. XRD, AFM, and UV-spectro-photometry were used to characterize the films structure, surface roughness and optical properties. The XRD spectra showed that the nanocrystalline films are of monocrystalline nature. AFM has confirmed the nanocrystalline character of tellurium-doped ZnO. The transmission of exposed films has been decreased with the increase of annealing temperature. The average transmission of all the films has been revealed to be higher than 80%. The optical band gap varies slightly with post-annealing temperature.

THE INFLUENCE OF POST-ANNEALING CdS THIN FILMS GROWN ON ZnO SEED LAYER FOR CdTe SOLAR CELLS

In this study, the effect of post-annealing temperature in CdS thin films grown on ZnO seed layer was investigated. CdS thin film and ZnO seed layer were coated by chemical bath deposition method and solution dropping technique, respectively. The structure of the post-annealed samples at 350°C and 400°C consisted of cubic CdS and CdSO3 oxide phases. As a result of recrystallization at 450°C, both hexagonal CdS and cubic CdO phases were formed. While the absorption edge was observed at around 500 nm in all samples, the best transmittance was observed in the sample annealed at 400°C. PL spectra proved the existence of defect types such as deep emission, sulfur vacancy for all samples. Ellipsometer measurements showed that the highest refractive index was in the sample annealed at 400°C. Among the samples, it was concluded that the most suitable window structure for CdTe solar cell applications is CdS thin film post-annealed at 400°C.

Effect of annealing temperature on the physical properties of NiO thin films and ITO/NiO/Al Schottky diodes

Herein, fabrication and characterisation of p-NiO/Al Schottky barrier diodes have been realised by dc reactive magnetron sputtering. In addition, effect of post-annealing temperature was studied. A detailed investigation on the physical properties of the NiO thin films was carried out using structural, morphological, optical, and spectroscopic characterisation tools. The metal–semiconductor interface behaviour has been analysed by current–voltage characterisation by implementing the Thermionic emission and Chueng model. The fabricated diode rectification ratio of 103 has been recorded at pm 3V, and barrier height varied from 0.53 to 1.10 eV as a function of annealed treatment. A space charge-limited conduction mechanism and tunnelling through the interface trap density of p-NiO/Al Schottky diodes were explained by power law characteristics. Furthermore, we have evaluated the Schottky device's electrical characteristics through the ac measurements which include capacitance densities, dielectric constants, tangent loss, AC conductivity, and Nyquist plots. The present work could provide a better understanding and insight into the p-NiO/Al Schottky junction.

Hydrothermally synthesized ZnO and Z-rGO nanorods: Effect of post-annealing temperature and rGO incorporation on hydrogen sensing

Hydrothermally synthesized ZnO and Z-rGO nanorods: Effect of post-annealing temperature and rGO incorporation on hydrogen sensing

From coating to doping: Effect of post-annealing temperature on the alumina coating of LiNi0.5Mn1.5O4 cathode material

Spinel LiNi0.5Mn1.5O4 is considered as one of the most promising cathode materials due to high working voltage and high energy density. However, the fast capacity degradation, mainly induced by the instability of electrode/electrolyte interface and bulk structure, heavily prevents its commercial application. To alleviate above two issues, LiNi0.5Mn1.5O4 material was first coated with Al(OH)3 via double hydrolysis reactions between NaAlO2 and AlCl3·6H2O, where the corrosion of LiNi0.5Mn1.5O4 material is avoided by controlling the feeding sequence, and the uniform coating of Al(OH)3 on particle surface is achieved by controlling the feeding rate. The Al(OH)3-coated LiNi0.5Mn1.5O4 material was post-annealed at different temperatures, and the effects of different post-annealing temperatures on the structure, morphology and electrochemical performance of LiNi0.5Mn1.5O4 material were systematically investigated. It is found that the LiNi0.5Mn1.5O4 material after post-annealing treatment at 600 ​°C exhibits the optimal rate and cycling performances, which can be mainly attributed to the synergistic effect of Al2O3 surface coating and doping. The uniform and thin Al2O3 coating layer can avoid the direct contact of electrode with electrolyte, capture corrosive HF and increase oxygen vacancy on particle surface, while Al3+ doping can eliminate LixNi1-xO impurity phase, reduce Mn3+ content, strengthen the spinel structure and make Li+ ions diffusion easier, thus leading to the simultaneous improvement of interfacial and structural stability of LiNi0.5Mn1.5O4 material.

Effects of post-annealing temperature and micropillar shape on physical properties of micropillar-type multiferroic composite thin films

Microplate (MP) and microrod (MR)-type CoFe2O4/(Bi3.25Nd0.65Eu0.10)Ti3O12 composite thin films were fabricated by a combination of reactive ion etching and metalorganic chemical vapor deposition. The effects of post-annealing temperature on the structural, magnetic, electrical, and magnetoelectric (ME) properties of the films were investigated. Based on the results, the optimal ferroelectric pillar structure to obtain a large ME voltage coefficient (α ME ) was determined. The electrical insulation properties for the films improved with increasing post-annealing temperature. On the other hand, magnetic and ferroelectric properties were degraded at high-temperature. Judging from the structural, magnetic, electric, and ME properties, the optimum post-annealing temperature was 700 °C. The shape of the ferroelectric layer had a significant influence on the ferroelectric properties and consequently on α ME . The MR shape exhibited a smaller clamping effect than the MP shape, producing a greater ME effect. The α ME for the MR-type film post-annealed at 700 °C was 5.5 mV cm−1 Oe−1.

Effect of Annealing Temperature on Properties of Tin Oxide Films Prepared by Electrostatic Deposition Technique

Abstract In this work, tin oxide films were prepared by electrostatic spray deposition technique. The effect of post annealing temperature on properties of prepare film was performed. The structural, surface morphology and optical properties of tin oxide films were characterized by X-ray diffraction, field-emission scanning electron microscope, and UV-Visible spectrophotometer. The crystalline size is found to increase with increase the annealing temperature. Moreover, the effect of annealing temperature on physical properties of tin oxide films has been performed

Post-annealing effect on the electrochromic properties of WO3 films

Abstract The idea of Internet of Things (IoT) has brought about the innovation of smart materials and devices which affect our everyday life. One of the technologies associated to the IoT is the electrochromic (EC) smart windows and the key material is tungsten oxide (WO3). WO3 is considered as the best candidate due to its superior EC properties for example high optical modulation and high colouration efficiency. In this work, the structural properties of WO3 films were manipulated by varying the post annealing temperature between 27 °C and 450 °C. The WO3 films annealed at different temperature were characterised for their structural, morphological, optical and EC properties using X-ray diffraction spectroscopy (XRD), scanning electron microscopy (SEM), optical transmittance study, cyclic voltammetry (CV) and chronoamperometry (CA) measurements. The effect of post annealing temperature will be analysed and investigated which is important for smart window performance optimisation.

Spark plasma sintering of SnO2 based varistors

In this research, for the first time, SnO2-based varistors were fabricated via spark plasma sintering technique (SPS) and the microstructure and electrical properties of these varistors were investigated. Furthermore, the effect of post-annealing temperature in oxygen atmosphere on electrical properties of the SPSed samples was studied. The SPS process was performed at the sintering temperatures of 600, 650, and 700 ᵒC for 15 min with a maximum pressure of 90 MPa under vacuum condition. The SPSed sample which was sintered at 650 ᵒC possessed maximum density of 98% and the ultra-fine-grained microstructure with the mean grain size of 380 nm. Surprisingly, all SPSed samples exhibited Ohmic behavior with very low electric resistances. After post-annealing in oxygen atmosphere, Ohmic to non-Ohmic transition was observed in SPSed samples. The oxygen deficiency during the SPS process was responsible for the Ohmic characteristic of SPSed samples. Post-annealing of SPSed samples in the oxygen atmosphere resulted in Schottky barriers formation through oxygen adsorption at grain boundaries. The sample post-annealed at 1050 ᵒC presented the best non-Ohmic parameters including high breakdown electric field of 4500 V/cm and the nonlinear coefficient of 13. These electrical parameters are comparable with the conventional-sintered samples which was sintered at 1300 ᵒC and its breakdown electric field and nonlinear coefficient were equal to 900 V/cm and 8, respectfully.

Rapid and Scalable Wire-bar Strategy for Coating of TiO2 Thin-films: Effect of Post-Annealing Temperatures on Structures and Catalytic Dye-Degradation.

Titanium dioxide (TiO2) thin films were rapidly coated on Corning glass substrates from the precursor solution using the wire-bar technique at the room temperature and then post-annealed at 400, 500 and 600 °C for 1 h under atmospheric conditions. The structural, morphological, optical, wettability and photocatalytic properties of the films were studied. X-ray diffraction analysis confirmed the formation of an anatase TiO2 structure irrespective of the post-annealing temperatures. The optical transparency of the films in the visible range was measured to be > 70%. A water contact angle (WCA) of ~0° was observed for TiO2 thin-film, post-annealed at 400 °C and 500 °C. However, WCA of 40.3° was observed for post-annealed at 600 °C. The photocatalytic dye-degradation using post-annealed thin-film was investigated indicating a steady improvement in the dye-degradation percentage (from 24.3 to 29.4%) with the increase of post-annealing temperature. The demonstrated TiO2 thin-films deposited by wire-bar coating technique showed promises for the manufacturing of large-area cost-effective self-cleaning window glass.

Effect of post-annealing temperature on linear and non-linear optical properties of sol-gel spin coated CdS thin films

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Electronic properties of Ga-In-Zn-O (GIZO) thin films: Effect of post-annealing

Effect of post annealing temperature on electronic properties of Ga-In-Zn-O (GIZO) have quantitatively studied by using reflection electron energy loss spectroscopy (REELS), x-ray photoelectron spectroscopy (XPS), and x-ray absorption fine structure (XAFS) spectra. The band gap values of GIZO are 3.1 eV, 3.5 eV, and 3.8 eV, at room temperature (as deposited), post-annealing at 600 °C, and 700 °C, respectively. The composition of Ga increased and Zn reduced with increasing post-annealing temperature. The formation of Ga-(Ga,Zn) and Zn-(Zn,Ga) bonds in GIZO thin film annealed at 700 °C was confirmed by XAFS study. The electronic properties of GIZO thin films strongly affected by the bonding formation of Zn-O and Ga-O as the effect of annealing temperature.

The effect of post annealing temperature on grain size of indium-tin-oxide for optical and electrical properties improvement

Abstract Background (Problem) Indium tin oxide (ITO) is a transparent conductive oxide (TCO) thin film used as a transparent electrode. Given its high demand for the manufacture of transparent electrodes (high visible light transmittance, low resistance) in applications such as liquid crystal displays, touch screens, light emitting devices and solar cells, ITO thin films have attracted immense research interest. Objectives This study determines the effect of grain size on the optical and electrical properties of the ITO thin films under different annealing temperatures. Materials and methods ITO thin film was deposited at room temperature by a high frequency magnetron sputtering method using a target composed of In2O3 and SnO2. The structural, optical and electrical properties of the thin films annealed at 250 °C, 350 °C, 450 °C and 550 °C for 1 h were then analyzed. Results The research shows the grain size of indium-tin oxide thin films is strongly related to annealing conditions. The grain size was found to increase with increasing annealing temperature, although the crystal structure did not change for all the samples. It was observed that the lowest resistivity (500 × 10−4 Ω-cm) and highest optical transmittances (90–98%) of ITO films were obtained at annealing temperature of 450 °C. At low annealing temperatures, the measured resistivity is dependent on the effect of grain size, where it decreases with increasing grain size. Conclusion This work showed that the grain size of ITO thin films is strongly influenced by post annealing technique and conditions applied, thus providing a tool for enhancing the optical and electrical properties of the film.

Effect of Solution pH and Post-annealing temperatures on the Optical Bandgap of the Copper Oxide Thin Films Grown by modified SILAR Method

AbstractCuprous oxide (Cu2O) thin films have been grown on both soda lime glass (SLG) microscope slides and Fluorine-doped Tin Oxide (FTO) substrates by a modified SILAR technique. The pH level of the bath solution was systematically varied in the range of 4.50 – 7.95 to elucidate their effect on the physical properties of the deposited product. The prepared films showed compact surface morphology composed of spherical grains evident from their SEM images. The XRD measurement showed that the as-deposited films were single phase Cu2O with (111) preferred orientation and this texturing was found to be increasing with increasing pH and annealing temperature. The annealed Cu2O films were found to be stable up to 200 °C and completely converted to cupric oxide (CuO) phases when the temperature reached to 350 °C. The estimated optical bandgaps of the as-grown samples were found in the range of 2.28 – 2.48 eV using UV-Vis-NIR transmission data and showing a bandgap narrowing trend with the decreasing level of solution pH. The effect of post-annealing temperatures (75-350 0C) on the as-deposited films was also studied and found to be crucial to control the optical bandgap (1.44 – 2.13) eV and electrical properties of the films. The sheet resistance of the as-deposited samples was found to be decreasing from 4120 MΩ/square to 800 MΩ/square while grown with increasing acetic acid content in the precursor solutions and decreasing up to 2.66 MΩ/square while annealing up to 250 °C in the air.

Effect of post-annealing on microstructure and piezoelectric properties of ZnO thin film for triangular shaped vibration energy harvester

In this paper, a triangular shaped piezoelectric vibration energy harvester (TS-PVEH) with zinc oxide (ZnO) thin films as the piezoelectric layer is reported. The effect of post-annealing temperature on the microstructure and piezoelectric performance of ZnO thin film deposited by magnetron sputtering method is investigated firstly. The results show that the optimum post-annealing temperature of 150 °C was the most beneficial to improve the piezoelectric properties of ZnO thin films. Four prototypes of TS-PVEH with different structure parameters are fabricated and optimized. The simulation and experiment results indicate that the height and width of the triangular structure have a significant influence on the vibration mode and the output performance of TS-PVEHs. The optimization results indicate that the third prototype has the best output performance. Its open-circuit voltage and short-circuit current are 290 mV and 1.25 μA, respectively, when the vibration acceleration is 5 m/s2 and the frequency is 56 Hz. Moreover, it has the highest load power density of 0.035 μW/cm2 when the load is 0.1 MΩ.

Magnetron sputtered LSC thin films for solid oxide fuel cell application

In this study, La0.6Sr0.4CoO3-δ (LSC) thin films were deposited by pulsed DC magnetron sputtering at oblique angle of the LSC target. The effect of post-annealing temperature in the range of 600-1000°C on the film crystalline structure was investigated. The phase composition, crystalline structure and surface morphology of the films were determined using X-ray diffraction, scanning electron microscopy and atomic force microscopy, respectively. Anode-supported solid oxide fuel cells (SOFCs) with bi-layered thin-film yttria-stabilized zirconia (YSZ) / gadolinium-doped ceria (GDC) electrolyte and an LSC thin film interlayer were fabricated. Polarization curves were measured in the temperature range from 700 to 800°C. It was shown that the LSC interlayer improves SOFC power density. Our results demonstrate that magnetron sputtering provides a low-temperature synthesis route for realizing thin LSC films for intermediate-temperature SOFCs.