Effect Of Post-annealing Treatment Research Articles

Influence of post-annealing treatment on the performance of perovskite solar cells with different hole transport layers

The performance of perovskite solar cells (PSCs) is one of the key factors influencing their industrialization and market competitiveness. In this paper, post-annealing treatment, which is an effective and simple method, was used to enhance the performance of PSCs. PSCs with different hole transport layer (HTL) were prepared, and the effect of post-annealing treatment on the performance of PSCs was investigated. The results showed that post-annealing treatment could enhance the carrier extraction ability of HTL, reduce the defects in the perovskite layer, decrease non-radiative recombination, and effectively improve the device performance when PTAA was included in the HTL. After annealing treatment, it was found that the PCSs with NiOx/PTAA as the transport layer, the champion device of PSCs can achieve a PCE of 21.21 %. Compared to devices using only NiOx and PPAA as hole transport layers, the PCE increased by 36.9 % and 3 %, respectively. Meanwhile, when using NiOx/PTAA as the transport layer, compared to devices without annealing treatment, the PCE increased from 17.95 % to 21.21 %, resulting in an 18.2 % enhancement. The obtained results in this work can provide an important theoretical basis for researchers to understand the physical mechanism of post-annealing treatment on device performance and fabricate perovskite solar cells with high-performance.

Effect of post-annealing treatment on structural, optical and photocatalytic properties of TiO2 nanoparticles prepared via pulsed laser ablation in liquid

Ultrasmall TiO2 nanoparticles were synthesized through pulsed laser ablation of a metal titanium target in liquid followed by thermal annealing treatment. The impact of post-annealing treatment on the structural, morphological, optical properties, and the photocatalytic activity of the synthesized TiO2 nanoparticles have been investigated through a variety of analytical techniques, including X-Ray diffraction, transmission electron microscopy, ultraviolet-visible diffusion reflectance spectra, X-ray photoelectron spectroscopy. The results reveal that annealing temperature significantly improved the crystallinity of laser ablated TiO2 nanoparticles and modified the chemical states of surface elements. Defects introduced by laser ablation, which serve as electron traps, combined with enhanced crystallinity resulting from thermal annealing, have improved the photocatalytic degradation performance of TiO2 nanoparticles. Specifically, TiO2 nanoparticles annealed at 300 ℃ exhibited optimal photocatalytic performance in decomposition of model dye under the irradiation from xenon lamp, demonstrating the critical role of annealing in improving photocatalytic properties. This study not only broadens the comprehension of the impact of post-treatment on the characteristics of laser-ablated TiO2 nanoparticles nanoparticles but also highlights their potential for effective wastewater remediation.

Effective Non-Radiative Interfacial Recombination Suppression Scenario Using Air Annealing for Antimony Triselenide Thin-Film Solar Cells.

Antimony triselenide (Sb2Se3) has become a very promising candidate for next-generation thin-film solar cells due to the merits of their low-cost, low-toxic and excellent optoelectronic properties. Despite Sb2Se3 thin-film photovoltaic technology having undergone rapid development over the past few years, insufficient doping concentration and severe recombination have been the most challenging limitations hindering further breakthroughs for the Sb2Se3 solar cells. Post-annealing treatment of the Sb2Se3/CdS heterojunction was demonstrated to be very helpful in improving the device performance previously. In this work, post-annealing treatments were applied to the Sb2Se3/CdS heterojunction under a vacuum and in the air, respectively. It was found that compared to the vacuum annealing scenario, the air-annealed device presented notable enhancements in open-circuit voltage. Ultimately a competitive power conversion efficiency of 7.62% was achieved for the champion device via air annealing. Key photovoltaic parameters of the Sb2Se3 solar cells were measured and the effects of post-annealing treatments using different scenarios on the devices were discussed.

Effects of annealing treatment on microstructure and mechanical properties of laser melting-deposited VCoNi medium-entropy alloy

Additive manufacturing (AM) is a promising approach to producing high- or medium-entropy alloys (HEAs or MEAs) with excellent properties. However, some undesirable microstructural defects and unstable precipitated phases were formed owing to the repeated heating and cooling steps and the rapid solidification nature of the AM process. Annealing treatment after AM fabrication is often beneficial for adjusting the comprehensive mechanical properties and stabilizing the microstructures. In this study, a VCoNi MEA single wall sample was fabricated successfully via laser melting deposition (LMD), and the effects of post-annealing treatments on the microstructures and mechanical properties were explored. The grain size and σ-phase particle size increase and the σ-phase particles undergo fragmentation, spheroidization, and coarsening during annealing. As the annealing time increases, the tensile strain increases, but the tensile strength decreases. An excellent combination of strength and ductility can be obtained after annealing for 1.5 h (The yield strength, ultimate tensile strength, and tensile strain are 741.2 MPa, 1287.8 MPa, and 30.5 %, respectively). HDI hardening is the most important strengthening mechanism in this work. The decrease in tensile stress after the annealing treatment is mainly attributed to the decrease of heterogeneity of microstructure, and the increase in tensile strain after the annealing treatment is mainly attributed to the decrease of the pores and the spheroidization of the rod-like σ-phase particles. This work provides practical insight into adjusting the microstructure and comprehensive mechanical properties of HEAs and MEAs for AM.

Optimization of the photoelectric performances of Mg and Al co-doped ZnO films by a two-step heat treatment process

Mg and Al co-doped ZnO (AZMO) films were prepared by magnetron co-sputtering to improve the optical and electrical performances of the ZnO-based films simultaneously. A two-step heat treatment process was introduced to obtain high-quality AZMO films. AZMO films were first deposited with substrates heating of 300 °C and then annealed at 500 °C in vacuum. The individual and coupling effects of substrate heating during sputtering deposition and post-annealing treatment on AZMO films were investigated. The results show that substrate heating during sputtering deposition is mainly on increasing the grain size and crystallinity of AZMO films. However, the effects of post-annealing treatment are mainly on making Mg and Al atoms move to the lattice points and ionize to from MgZn and AlZn. Besides, post-annealing treatment can effectively desorb adsorbed oxygen from the surface or grain boundaries of AZMO films and also make lattice oxygen break away from the lattice and change into oxygen vacancy. Compared with one-step heat treatment alone, it is with the two-step heat treatment process that the coupling effects can be exerted by combining the different effects of the two heat treatments, so as to achieve more performances optimization of AZMO films.

Effect of post-annealing treatment on the thermoelectric properties of Ag2Se flexible thin film prepared by magnetron sputtering method

Flexible thermoelectric power generation devices can help solve the power supply problem of wearable electronic devices. Herein, single-phase Ag2Se films with a thickness of less than 500 nm were deposited on flexible polyimide substrates via magnetron sputtering. The microstructure, chemical composition, and thermoelectric properties of the films were investigated at different annealing temperatures (523 K–673 K). After annealing, the X-ray diffraction (XRD) test showed that the film had obvious preferential growth in the (002) and (004) crystallographic directions. Scanning electron microscopy (SEM) showed that with increasing annealing temperature, the size of the grains initially increased and subsequently decreased. Finally, after annealing at 623 K for 20 min, the film obtained a peak power factor of 526.86 μW∙m−1∙K−2. A six-leg flexible generator comprising Ag2Se films has a maximum power density of 7.52 W∙m−2 (50 K temperature difference). After 1000 bending times, the resistivity of the device changed by only 14.11 %, and the actual application test revealed an output voltage of 12.3 mV and a power of 23.49 nW under a temperature difference of 22.2 K. This work demonstrates that thermal treatment of thin films prepared by magnetron sputtering is a remarkable approach to increase thermoelectric performance, providing an efficient fabrication scheme for the development of environmentally friendly and wearable flexible thermoelectric devices.

Phase transformation of sputtered hafnium oxide by post annealing treatment and its effect on the amorphous Si-In-Zn-O thin film transistor

The effect of post annealing treatment on the phase transformation and the electrical properties of the sputtered hafnium oxide (HfO2) is investigated. As-deposited HfO2 films were annealed at 200 and 400 ∘C in ambient conditions. Film annealed at 200 ∘C is amorphous, but further annealing at 400 ∘C crystallizes it into the monoclinic structure. Amorphous films exhibit a higher bandgap (≥ 5.8 eV) than the monoclinic film (≈ 5.65 eV). The electrical characteristics of the Metal-Insulator-Metal devices reveal a nonlinear capacitance with respect to the voltage. The nonlinearity is predominant in the as-deposited film due to the oxygen vacancy related defects formed during the deposition. However, excess Hf-O bond formation occurs with annealing at higher temperatures, reducing the capacitance-voltage curve’s nonlinearity. The dielectric constant of the as-deposited, 200, and 400 ∘C annealed films are estimated as 22.35, 22.64, and 20.57, respectively. The increment in the dielectric constant at 200 ∘C is due to its amorphous phase and reduced defects. Amorphous Si-In-Zn-O thin film transistors fabricated using the as-deposited and annealed hafnium oxide as gate insulator show almost similar threshold voltage of ≈ −1 V. The transistor with hafnium oxide annealed at 200 ∘C shows the highest on current (1.04 × 10−6 A) followed by as-deposited (6.82 × 10−7 A) and 400 ∘C annealed device (5.86 × 10−7 A), respectively. Moreover, the interface state density increases monotonically from 3.98 × 1012 to 1.11 × 1013 cm−2 for as-deposited and 400 ∘C, respectively. The increment in the interface state density is due to the grain boundary formation due to the crystallization of HfO2.

The effect of post-annealing treatment on the structural and optoelectronic properties of solution-processed TiO2 thin films

The effect of post-annealing treatment on the structural and optoelectronic properties of solution-processed TiO2 thin films

Effect of annealing treatment on microstructure and mechanical properties of cold sprayed TiB2/AlSi10Mg composites

Cold spray allows for fabricating metal matrix composites or repairing damaged components in a scalable way with a high deposition rate. Nevertheless, the poorly bonded interfaces (both metallic splats/splats and metallic splats/reinforcements) and pores in the composite deposit result in undesirable mechanical performance, which limits its applications for load-bearing components. In this study, a special designed composite powder reinforced with in-situ TiB2 particles was used as the feedstock to produce TiB2/AlSi10Mg composite components by cold spray additive manufacturing. Following this, the effect of post-annealing treatment on interfaces and micro-pores healing, microstructure evolution, and mechanical properties of the cold sprayed TiB2/AlSi10Mg composites was investigated in terms of X-ray diffraction, electron backscatter diffraction, transmission electron microscopy, and tensile test. The cold sprayed composite exhibited a bimodal structure with ultrafine grains formed at the inter-splat boundaries due to dynamic recrystallization induced by intensive plastic deformation of the particles. In addition to the uniformly dispersed TiB2 nanoparticles, some aggregated clusters remained embedded in the Al matrix. Tensile tests revealed that the as-sprayed deposits possessed very high tensile strength but almost no toughness due to the poorly bonded inter-splats and enhanced work hardening effect. Significant improvement in ductility was achieved in the annealed samples through improvement of metallurgical bonding between the deformed splats, release of residual stress, and static recrystallization. Interestingly, when the annealing temperature was increased up to 500 °C, both the pure AlSi10Mg and TiB2/AlSi10Mg composite samples fractured at a very early stage due to the presence of large pores (>20 µm) which may originate from the moisture of initial powders. The in-situ formed TiB2 nanoparticles play an important role in strengthening the Al matrix, meanwhile, maintaining a good ductility due to the robust interface bonding. This study demonstrates the potential of using a gas-atomized composite powder to produce high-performance metal matrix composites by cold spray additive manufacturing followed by annealing treatment.

Effect of post-annealing on the microstructure and mechanical properties of nanostructured copper

Abstract In the current research, the effect of post-annealing treatment at 200 °C with four different holding times of 5, 10, 30, and 60 min on the asymmetrically cold-rolled pure copper was investigated. The microstructural evolution (via optical microscopy and scanning electron microscopy), mechanical properties (by tensile and hardness tests), and electrical conductivity of the post heat-treated copper sheets were evaluated. The static recrystallization (SRX) took place at a short annealing time due to the large strain stored energy caused by the asymmetric cold rolling as well as the presence of particles. The average grain size of the post-annealed sample for 5 min was about 96 nm. The copper after 60 min post-annealing consisted of many coarse polygonal grains, a few small grains, and multiple twinning (twin chains). The formation of multiple twinning and twin chains was due to the low-temperature annealing (200 °C) of rolled copper. The tensile properties indicated that the strength had a relatively low sensitivity to the increment of annealing time and the produced pure copper exhibited superior thermal stability. The formation of twin chains and the existence of copper oxide particles were responsible for this unusual behavior. The copper annealed for 60 min had a low YS-to-UTS ratio (0.378) and a high work hardening rate, which were equivalent to high formability. For the low annealing times of 5 and 10 min, there were both shear and equiaxed dimples on the fracture surface indicating a combination of ductile shear and ductile fractures. When the time of post-annealing was higher than 30 min, only the ductile dimples could be observed on the fracture surface. The post-annealing treatment for 60 min increased the electrical conductivity to from 84.10 to 87.52 %IACS due to the occurrence of recovery, recrystallization, and grain growth. Finally, it was found that adopting a high enough pre-deformation (96% strain) and a suitable annealing time (60 min) at a low annealing temperature (200 °C) in the pure copper could make a good balance between tensile and electrical properties.

Subtly adjusted active layer self‐assembly process for efficient organic solar cells

AbstractThe phase separation degree of active layers plays a vital role in enhancing the power conversion efficiency of organic solar cells. Two post treatments were employed to optimize the phase separation degree of active layers by subtly adjusting the self‐assembly process for SMPV1:PC71BM based active layers (SMPV1, 2,6‐bis[2,5‐bis(3‐octylrhodanine)‐(3,3‐dioctyl‐2,2':5,2''‐terthiophene)]‐4,8‐bis((5‐ethylhexyl)thiophen‐2‐yl)benzo[1,2‐b:4,5‐b']dithiophene; PC71BM, [6,6]‐phenyl‐C71‐butyric acid methyl ester). In this work, a power conversion efficiency of 7.93% was obtained for devices with an as‐cast active layer, which is close to the highest values reported for SMPV1 based devices. The power conversion efficiency was further increased to 8.64% or 8.99% for active layers with thermal annealing or thermal annealing together with solvent vapor annealing, respectively. The enhanced performance is mainly attributed to more efficient photon harvesting and charge transport induced by the post annealing treatment of the active layers. The face‐on molecular orientation of SMPV1 is increased for active layers with post annealing treatment, which is beneficial for charge transport along directions perpendicular to the substrate. This work further confirms the positive effect of post annealing treatment on the performance improvement of organic solar cells. © 2019 Society of Chemical Industry

Effect of post annealing treatment on electrical and structural properties of zinc oxide nanostructures

This paper work presents the effect of post annealing treatment on electrical and structural properties of nanostructured Zinc Oxide (ZnO) which was fabricated by hydrothermal process. I-V measurement shown the nanostructured ZnO exhibit Schottky conductive mechanism. The resistance of nanostructured ZnO was reduced as respected to the annealing temperature. XRD and EDX analysis confirmed the presence of ZnO element of Si substrate. Finally, FESEM analysis indicated a small nanoparticle growth on Si surface have 28.64 nm of average diameter size. These experiment results revealed, annealing treatment might be used to assist the formation of nanostructured ZnO on bare substrate.

Effect of the AlN interlayer on electroluminescent performance of n-SnO2/p-GaN heterojunction light-emitting diodes

Light emitting diodes (LEDs) based on n-SnO2/p-GaN heterojunction were fabricated by pulsed laser deposition (PLD). The effects of post-annealing treatment and interfacial layers on electroluminescence (EL) of n-SnO2/p-GaN were investigated. After annealing in vacuum, all the LED devices with different interfacial layers exhibit a nonlinear current-voltage behavior. The SnO2/p-GaN light emitting diodes exhibit two emission peaks, a violet peak (410 nm) and the broad yellow-orange emission band (600–700 nm), whereas only the yellow-orange EL spectra could be found in the SnO2/AlN/p-GaN. Using the band diagram, the carrier blocking process by different interfacial layer and the electroluminescence mechanisms of heterojunction LEDs were discussed in detail.

Improvement in microwave dielectric properties of Sr2TiO4 ceramics through post-annealing treatment

Sr2TiO4 ceramics were synthesized via the conventional solid-state reaction process, and the effects of post-annealing treatment in air on the microwave dielectric properties and defect behavior of title compound were investigated systematically. The Q × f values could be effectively improved from 107,000 GHz to 120,300 GHz for the specimens treated at 1450 °C for 16 h. The thermally stimulated depolarization currents (TSDC) revealed two kinds of defect dipoles [ $$ \left({\mathrm{Ti}}_{\mathrm{Ti}}^{\hbox{'}}-{V}_{\mathrm{O}}^{\bullet \bullet}\right) $$ and $$ \left({V}_{\mathrm{Sr}}^{"}-{V}_{\mathrm{O}}^{\bullet \bullet}\right) $$ ] and oxygen vacancies $$ \left({V}_{\mathrm{O}}^{\bullet \bullet}\right) $$ were considered the main defects in Sr2TiO4. Under a post-annealing treatment in air, the concentrations of such defects in the ceramics decreased. Meanwhile, the impedance spectrum revealed the activation energy of the grain boundaries increased. These evidences could account for the improvement of Q × f values. Accompanied with a high er of 40.4 and a large τf of 126 ppm/°C, the enhanced high-Q Sr2TiO4 ceramics can be good candidates for applications in wireless passive temperature sensing.

Tuning the Luminescent Properties of Ytterbium Doped AlNxOy Thin Film Materials Libraries Using a Combinatorial Approach

Rare-earth doped wide bandgap semiconductors give rise to many different luminescent applications. One main focus lies on electroluminescent devices due to the electronic behavior of the semiconductor host material. This kind of host materials allow the application in direct current as well as in alternating current electroluminescent devices with a generally low power consumption [1]. Using thin film devices makes it easy to design and tune the properties of electroluminescent devices. In the easiest form an electroluminescent device consists of a bottom electrode, the active material and a transparent top electrode. One candidate for the host material might be aluminum nitride AlN [2,3]. AlN is the semiconductor with the widest bandgap of 6.2 eV in its crystalline form. This leads to a good transparency but at the same time AlN still behaves like a semiconductor and is therefore widely used in electronic devices. Aluminum oxide, on the other hand, is an insulator with even higher transmittance and low refractive index. Both might be interesting candidates in light emitting devices. To obtain, for example, an infrared emitter, different rear earth materials can be used as dopant of the host material. Ytterbium is emitting with a wavelength of 980 nm, whereas erbium is emitting at 1535 nm [4]. One new approach to obtain and tune the properties of thin film devices is the deposition of material libraries. Using different approaches such as gradient co-deposition or mask based deposition opens up the possibility to produce a wide variety of different materials compositions on one single substrate. Adequate analytical screening methods allow the fast, easy and cheap evaluation of the interaction of different properties in a suitable range of interest [5]. In the presented work, the luminescent and optical properties of magnetron sputtered amorphous ytterbium doped aluminum oxynitride will be shown depending on the concentration of the ytterbium doping in a range of 0.9 to 4.2 at% as well as the ratio of oxygen to nitrogen of 0.5 to 3.5. To obtain a materials library the thin film was intentionally co-sputtered with a compositional gradient using two separate targets, a pure Yb and a pure AlN target with an unbalanced gas flux. Furthermore the activation of the rare-earth ions due to a temperature treatment in a range of 550 to 750°C as determined. It could be shown, that the emission is significantly higher at low oxygen concentrations meaning that the material closer to AlN is more favorable for the application in luminescent devices. This behavior could also be attributed to the activation energy of the rare-earth ions which was calculated from the intensity vs. concentration curves [6] of the materials libraries. Furthermore, the optical properties of the host material where investigated by means of the band gap and the refractive index. The presented results will give a useful insight for the application of Yb:AlNxOy in electroluminescent devices and is furthermore a first step for the development of down-conversion thin films based on the co-doping of ytterbium and terbium [2] for different conversion applications. [1] V.I. Dimitrova, P.G. Van Patten, H. Richardson, M.E. Kordesch, Photo-, cathodo-, and electroluminescence studies of sputter deposited AlN:Er thin films, Appl. Surf. Sci. 175–176 (2001) 480–483.[2] K. Tucto, L. Flores, J. Guerra, J. Töfflinger, J. Dulanto, R. Grieseler, et al., Production and Characterization of Tb3+/Yb3+ Co-Activated AlON Thin Films for Down Conversion Applications in Photovoltaic Cells, MRS Adv. 2 (2017) 2989–2995.[3] K.Y. Tucto Salinas, L.F. Flores Escalante, J.A. Guerra Torres, R. Grieseler, T. Kups, J. Pezoldt, et al., Effect of Post-Annealing Treatment on the Structure and Luminescence Properties of AIN:Tb3+ Thin Films Prepared by Radio Frequency Magnetron Sputtering, Mater. Sci. Forum. 890 (2017) 299–302.[4] A. KENYON, Recent developments in rare-earth doped materials for optoelectronics, Prog. Quantum Electron. 26 (2002) 225–284.[5] S. Thienhaus, D. Naujoks, J. Pfetzing-Micklich, D. König, A. Ludwig, Rapid Identification of Areas of Interest in Thin Film Materials Libraries by Combining Electrical, Optical, X-ray Diffraction, and Mechanical High-Throughput Measurements: A Case Study for the System Ni–Al, ACS Comb.Sci. 16 (2014) 686–694.[6] J.A. Guerra, F. De Zela, K. Tucto, L. Montañez, J.A. Töfflinger, A. Winnacker, et al., Effect of thermal annealing treatments on the optical activation of Tb 3+ -doped amorphous SiC:H thin films, J. Phys. D. Appl. Phys. 49 (2016) 375104. Figure 1

Effect of post-annealing on the properties of Co-doped ZnO thin films deposited by channel-spark ablation

In this study, we report on the effect of post-annealing treatment on the structure and morphology of Co-doped ZnO (CZO) thin film nano-composites deposited on Si (100) by channel-spark pulsed electron beam ablation (PEBA) from a single target, CoxZn1-xO (x = 0.20). The as-grown CZO films have been deposited within the temperature range 350 °C–450 °C, at electron beam acceleration voltages of 15 kV and 16 kV, and a beam frequency of 4 Hz. The films have been subjected to thermal annealing at either 400 °C or 600 °C for one hour. The effect of post-growth annealing on film properties has been discussed in terms of surface morphology, chemical composition, chemical state, and crystal structure. Experimental results show that, overall, post-annealing treatment significantly affects the structural and morphological properties of the films. Films annealed at 400 °C have higher average particle size and degree of crystallinity of ZnO hexagonal wurtzite structure relatively to the films annealed at 600 °C. Films annealed at 400 °C exhibit larger content in hexagonal close-packed (hcp) metallic Co (Co°) compared to the films annealed at 600 °C and to as-grown films. Both x-ray diffraction (XRD) and x-ray photoelectron spectroscopy (XPS) indicate that enhanced growth of Coо is achieved at the annealing temperature of 400° C.

Bandgap engineering of InSb by N incorporation by metal-organic chemical vapor deposition

Bandgap engineering is necessary for the application of InSb in long wavelength infrared photodetection. InSbN alloys hetero-epitaxially were therefore deposited on GaAs substrate by metal-organic chemical vapor deposition (MOCVD), expecting a large band gap reduction by N incorporation for long wavelength infrared photodetection. The effects of post annealing treatment on the structural and optical properties of the grown InSbN alloy have been well studied. Photoluminescence measurement (PL) indicated that the longest PL wavelength obtained at 10 K is ∼7.2 μm for the InSbN alloys, which manifests an extension of PL wavelength as large as ∼ 1.8 μm in comparison to the undoped InSb epilayers, suggesting a successful band gap reduction by the N incorporation. X-ray photoelectron spectroscopy (XPS) measurements show that three kinds of nitrogen bonds co-exist in the alloys and their percentages vary with annealing conditions. This observation can explain the peak shifts of X-ray diffraction (XRD) and PL spectra. The comparison to our previous works reveals that the InSbN alloys grown on GaAs substrate can achieve more nitrogen incorporation and band gap reduction than the alloys grown on InSb and GaSb substrates.

Thermal annealing evolution to physical properties of ZnS thin films as buffer layer for solar cell applications

The conventional CdS window layer in solar cells is found to be hazardous for the environment due to toxic nature of the cadmium. Therefore, in order to seek an alternative, a study on effect of post-annealing treatment on physical properties of e-beam evaporated ZnS thin films has been carried out where films of thickness 150 nm were deposited on glass and indium tin oxide (ITO) substrates. The post annealing treatment was performed in air atmosphere within the temperature range from 100 °C to 500 °C. X-ray diffraction analysis reveals that the films on glass substrate are found to be amorphous at low temperature annealing (≤300 °C) while have α-ZnS hexagonal phase (wurtzite structure) at higher annealing. The patterns also show that the possibility of oxidation is increased significantly at temperature 500 °C which leads to decrease in direct band gap from 3.28 eV to 3.18 eV except films annealed at 300 °C (i.e. 3.39 eV). The maximum transmittance is found about 95% as a result of Doppler blue shift while electrical analysis indicated almost ohmic behavior between current and voltage and surface roughness is increased with post-annealing treatment.

Effect of Annealing Treatments on the Microstructure, Mechanical Properties and Corrosion Behavior of Direct Metal Laser Sintered Ti-6Al-4V

An experimental investigation on the effects of post-annealing treatments on the microstructure, mechanical properties and corrosion behavior of direct metal laser sintered Ti-6Al-4V alloys has been conducted. The microstructure and phase evolution as affected by annealing treatment temperature were examined through scanning electron microscopy and x-ray diffraction. The tensile properties and Vickers hardness were measured and compared to the commercial Grade 5 Ti-6Al-4V alloy. Corrosion behavior of the parts was analyzed electrochemically in simulated body fluid at 37 °C. It was found out that the as-printed parts mainly composed of non-equilibrium α′ phase. Annealing treatment allowed the transformation from α′ to α phase and the development of β phase. The tensile test results indicated that post-annealing treatment could improve the ductility and decrease the strength. The as-printed Ti-6Al-4V part exhibits inferior corrosion resistance compared to the commercial alloy, and post-annealing treatment can reduce its susceptibility to corrosion by reducing the two-phase interface area.

Effect of Post-Annealing Treatment on Mechanical Properties of ZnO Thin Films

Effect of Post-Annealing Treatment on Mechanical Properties of ZnO Thin Films