PLD Technique Research Articles

Laser wavelength effect on GaN nanostructure films morphological properties deposited by PLD technique

Laser wavelength effect on GaN nanostructure films morphological properties deposited by PLD technique

Q-switched Nd: YAG Fundamental and Second Harmonic Wavelengths Impact on Preparing Nb2O5 Thin Films by a PLD Technique: A Comparative study

We aim to study and investigate the structural, optical, topographical, and morphological properties of Nb2O5 thin films deposited under vacuum Q-switched Nd: YAG pulsed laser for the first time to the best of our knowledge. The obtained results of this study can contribute in different fields of applications including the optoelectronic and biomedical fields. The fundamental (1064 nm) and the visible second harmonic (532 nm) wavelengths were utilized for this purpose. The laser energy was fixed at 657 mJ. The number of pulses and the substrate temperatures were 200 laser shots and 450 ºC, respectively. The observed X-ray diffraction patterns were assigned for T-Nb2O5 that refers to the orthorhombic and H-Nb2O5 which is related to the monoclinic phases supported by Raman spectra analyses. Nb2O5 thin film deposited by Nd: YAG fundamental wavelength (1064 nm) showed a thicker film, a higher surface roughness and, on average, a larger particles size It also provided better matching of the lattice d-spacing with the standard d-spacing obtained by JPCDs cards 00-030-0873 and 00-009-0372. The optical properties including the band gap values for both direct and indirect transitions were estimated with the lower gap was reported for the thin film prepared at the fundamental wavelength. The photoluminescence analyses supported that the transitions of both prepared films were indirect. FE-SEM clarified the surface morphology of each prepared film. The EDX analyses provided the elemental compositions and the purity of the Nb2O5 prepared films.

Synthesis and characterization of (ZnO) 1−x (CuO)x films prepared by PLD technique for enhanced the solar cell efficiency

Synthesis and characterization of (ZnO) 1−x (CuO)x films prepared by PLD technique for enhanced the solar cell efficiency

To study structural morphological and ferromagnetic behaviour of Sn1−xMnxO2 thin films

SnO2 is diamagnetic in nature and represent paramagnetic, ferromagnetic and anti-ferromagnetic behaviours after inducing Mn in the host matrix. Mn doped SnO2 thin films prepared by PLD technique. XRD and AFM measurements confirm the reducing crystallite and grain size of the samples with increasing doping of Mn. In this research authors focused on magnetization effect of SMO thin films with the help of SQUID-VSM magnetometer. Magnetic analysis reflects strong ferromagnetic behaviour for (10 % Mn) doping and further increase upto (15 %) shift to ferromagnetic to anti-ferromagnetic behaviour. The above observation will be useful for the core elements for the spintronic devices.

Effect of Annealing Process on the Morphological, Optical and Electrical Properties of Cu:MnO Films Prepared by PLD Technique

In this study, Nd:YAG laser pulses with a wavelength of 1064 nm, a power of 500 mJ, a pulse width of 9 ns, and a repetition frequency of 6 Hz were used to hit a manganese oxide (MnO) target surface 300 times. Pure MnO and copper Cu-doped MnO (Cu:MnO) with different amounts of Cu (0.03, 0.05, 0.07, and 0.09 wt%) produced by PLD were studied. Cu:MnO thin films were annealed at 473 K, and their morphological, optical, and electrical characteristics were studied. The results of the atomic force microscopic (AFM) investigation of morphological properties showed that Cu dopant impacted the creation of roughness and particle size in MnO2 films. The optical transmission was examined using a UV-Vis spectrophotometer. The highest optical absorption was noted at 0.09 dopant content. The dielectric constants' real (εr) and imaginary (εi) components, as well as the extinction coefficient (k), refractive index (n), and other optical constants, were studied. At an annealing temperature of (473 K), Hall effect studies demonstrate that all produced films exhibit a P-type conductivity.

Effect of annealing process on structural and optical properties of Au-doped thin films (NiO:WO3) fabricated by PLD technique

Effect of annealing process on structural and optical properties of Au-doped thin films (NiO:WO3) fabricated by PLD technique

EFFECT OF CeO2 NANOPARTICLES ON THE STRUCTURAL AND OPTICAL PROPERTIES OF (SnO2:Pd) FILMS PREPARED BY PLD TECHNIQUE

In this paper, pure and doped (SnO2:Pd ) films with CeO2 nanoparticles prepared by PLD technique using a highly intense Nd:YAG laser beam at 600 mJ with a frequency of second radiation at 1064 nm (pulse width 9 ns) repeating frequency (6 Hz) for 400 laser pulses incident on the intended surface has been performed. The stabilized (SnO2:Pd) doped with cerium oxide were used for deposition of the thin films on glass with thickness 200nm±05. Films of SnO2:pd were prepared with different doping concentrations of CeO2(0, 0.05, 0.10,0.15,0.20 and 0.25) wt. The FTIR and UV-Visible spectrophotometer were employed to investigate the structural, and optical characteristics of the films, respectively. FTIR spectra of (SnO2:Pd)1-xCeO2x thin films show seven peaks were assigned at wavenumber range from 2869.73 cm-1 belong to stretching bond CH2 to 492.98 cm-1 belong to N-O which can be indicated by the vibrations mode .The optical results show that transmittance decreased drastically by increasing the doping ratio. In contrast with absorbance, it increased by increasing of the doping ratio of cerium oxide. The optical energy gap was found to change systematic sequence with increasing of CeO2 concentration. Also the optical constant with different CeO2 contents were determined..

The effect of interfacial charge-induced multiferroic properties of Bi0.993La0.007FeO3/BaTiO3 bilayer thin films: Performance modulation and energy storage applications

Multifunctional and multiferroic materials assure a tantalizing perspective of applications in next-generation microelectronics, memory, energy harvesting, and energy storage technologies. The current study aims to deposit a bilayer thin film of BLFO/BTO with varying top layer (BLFO) thickness on n-type Si and Pt/Ti/SiO2/Si (Pt-Si) substrate by the PLD technique. Bilayer films with dense and packed microstructures show evidence of both tetragonal (T) and rhombohedral (R) symmetry. The bilayer films exhibit remarkably enhanced saturation magnetization of 35.9 emu/cm3 and improved maximum polarization of 34 μC/cm2 at RT compared to single-layer films. Moreover, the higher top layer thickness (BTO/BLFO3) hetero-structures achieved a high recoverable energy storage density of 11.65 J/cm3 with an energy efficiency of 85 % simultaneously. These films display excellent energy storage performance and produce a maximum power density of 0.9 MW/cm3 at 100 Hz. Further, the leakage current density of BLFO/BTO3 film is found ∼102 times lower than the monolayer BTO thin film suggesting the lower oxygen vacancies, defects, and impurities in the bilayer stacked films with higher top layer thickness. The drop in leakage current density, slim hysteresis loop, and enhancement in large saturation polarization for BTO/BLFO3 highlight the improved result demonstrating the interface effect and coupling between ferroelectric and magnetic properties. Hence, the acquired ferroelectric and magnetic properties are promising for spintronic devices and energy storage capacitor applications.

Optimization of MPB for Sn Substituted Lead Bismuth Zirconate Titanate Thin Films by the Electromechanical Behavior Related to Energy Storage Capacity

In this article, we examined the electromechanical behavior of Sn-substituted Lead Bismuth Zirconate Titanate thin films (PBZST thin films). Using the pulsed laser deposition technique (PLD), the thin film growth parameters of bismuth-doped PZST close to MPB were adjusted by varying the ∼(Zr, Sn)/Ti ratios. Thin films (∼250 nm) with the stoichiometric formula Pb0.985Bi0.01(Zr0.7Sn0.3) x Ti1 – x O3, (x = 0.935, 0.940, 0.945, and 0.950) were grown on a Pt/TiO2/SiO2/Si substrate using PLD technique at optimized conditions. P-E loop confirms that MPB is near x = 0.945, and further PFM measurements also confirmed the same. Analyzing the PFM phase and amplitude hysteresis loops, local piezo-electric coefficient and remnant strain values were computed as d33 = 330 pm/V and 0.33 at the MPB composition (x = 0.945).

Structural and magnetic properties of YIG thin films deposited by pulsed laser deposition and RF magnetron sputtering technique

Yttrium iron garnet (YIG) has been extensively explored for its potential avenues in spintronic applications. A majority of these studies employ thin films grown by PLD at high substrate temperature, which generally leads to an interfacial dead layer with cations interdiffusion hindering their technological implications. In this communication, we report the growth of YIG thin films at room temperature by PLD and RF sputtering techniques. Detailed structural investigation confirms the thin films’ single-phase growth and epitaxial nature. We have a further detailed investigation of magnetic properties by dc magnetization, magneto-optical Kerr effect and FMR techniques. Although our thin films exhibit a comparatively lower magnetic performance in terms of saturation magnetization and damping constant, we have obtained a significantly lower interfacial dead layer thickness of ∼1 nm, which is quite promising for spin transport applications. The present study, therefore, calls for future studies for simultaneous optimization of magnetic performance and interfacial dead layer with room temperature grown YIG thin films by both PLD and RF sputtering methods.

Investigation of Structural, Optical and Electrical Properties of MnO Doped with Cu Thin Films Prepared by PLD Technique for Solar Cell Applications

In the current study, concentrated Nd:YAG laser pulses at 500 mJ with a second radiation at 1064 nm (pulse width 9 ns) and repetition frequency (6 Hz) for 300 laser pulses incident on the target surface were employed to coat glass substrates with MnO thin films. Using an X-ray diffractometer (XRD), an atomic force microscope (AFM), and a UV-Vis spectrophotometer, the structural, morphological, and optical characteristics of the films doped with different concentrations of Cu content (0.03, 0.05, 0.07, and 0.09) were examined. The results show that the films are polycrystalline, with the largest peak appearing at an angle of 35.31, or a reflection of (111). The crystalline size of the deposited thin films was calculated using Debye Scherer formula and found to increase from 11.8 nm for undoped MnO2 to 29.6 nm for doped (MnO) with the increase of Cu content from x=0 to x=0.09 at preferred orientation of (111). All the samples have a cubic structure. Also, the results showed that Cu content of the films affects the surface morphology. From the results of AFM analysis, it was found that the roughness and average diameter change when adding Cu to the structure, with the highest value occurring at Cu ratio 0.09 equal to 65.40 and 71.21 nm, respectively. UV–Vis spectrophotometer was used to investigate the optical transmission. It was found that when Cu content of films increased, the transmittance of films decreased. Hall Effect measurements show that all prepared films at RT have two type of conductivity P-type and n-type. The electrical characteristics of the (MnO)1-xCux/Si heterojunction Solar Cell have been studied and found that the efficiency (η) decreases with the increase of Cu content.

Rare Earth Doped Lead Zirconate Titanate Thin Films for Memory and Power Device Applications

We fabricated thin films of (PbZr0.53Ti0.47)O3 (PZT) and (PbZr0.53Ti0.47)0.90(LaxSc1-x)0.10O3 where; x= 0, 0.2, 0.4, 0.6 and 0.8 denoted as [abbr. PL10x] PL0, PL2, PL4, PL6, and PL8 respectively on the LSMO buffer layer (bottom electrode) by using a PLD technique. The X-ray diffraction peaks show a single-phase perovskite structure of thin films with a preferred (100) orientation that coincides with the MgO and has tetragonal phase symmetry (P4mm). Pt electrodes were deposited at the top of thin films as top electrodes. We achieved higher dielectric permittivity (ε’) for PL0 and PL6 compared to other compositions. We noticed that the role of increasing lanthanum content (decreasing scandium) resulted in the broadening of ε’ with temperature and ferroelectric phase transition decreased to 450 K. However, the scandium doping alone (PL0) didn’t lower the ferroelectric phase transition. We analyzed the temperature-dependent ε’ using the modified Curie-Weiss law. The PL0, PL6, and PL8 thin film capacitors exhibited relaxor ferroelectric properties that were further supported by the Vogel-Fulcher relation.The P-E hysteresis loops exhibited the role of lanthanum and scandium causing compositional changes in coercive fields. The P-E loops of PZT, PL2, and PL4 exhibited typical ferroelectric features. Whereas, PL0, PL6, and PL8 showed a relaxor ferroelectric behavior which was corroborated by the analysis of the dielectric data. The PL0 and PL6 thin films showed better spontaneous polarization Ps. We achieved superior energy storage performance Ure = 54.63 J/cm3 with η ~ 70% for PL0 and Ure = 26.54 J/cm3 with η ~ 66% for PL8 thin film capacitors. The study demonstrated the idea that by tuning La3+ and Sc3+ the dielectric and ferroelectric properties of thin films can be controlled for suitable electronic applications, such as memory, power devices, and energy storage.

Structural and optical characteristics of NiO films deposited using the PLD technique

NiO films were deposited on glass and Si(100) substrates by reactive pulsed laser deposition from the Ni target. Nd: YAG laser (1064 nm) was used. The oxygen pressure was between 0.05 and 0.3 Torr. The optimum conditions for a good-quality NiO film are an oxygen pressure of 0.1 Torr and a laser power of 410 mW. Preferred orientation changes from (200) to (220) and D decreases from 27 to ∼9 nm as the temperature increases from 200 to 300°C. The preferred orientation changes into (111), nanoparticles size reduces from 46 to 26 nm and D drops from 27 to 10 nm as laser power increases from 410 to 820 mW. The oxygen pressure is significantly affecting the composition and morphologies of the NiO films. The optical band gap was 3.35 eV.

Study of the characterizationn of CdTe thin films prepared by the pulsed laser deposition technique with different laser energies

This research studied the effects of different laser energies on structural and optical properties. We prepared CdTe thin films by PLD technique using an Nd:YAG laser with a wavelength of 1064 nm and different energies (400, 500, 600, and 700 mJ). The practical experiments were carried out at a temperature of 200 °C. XRD results revealed that all the prepared thin films have polycrystalline structures and cubic systems with average crystalline sizes of 34, 42, 54, and 57 nm for 400, 500, 600, and 700 mJ, respectively. We observed that the optical energy gap of CdTe thin films decreases with the increase of laser energy (1.87–1.58 eV). The topography of the surfaces of CdTe thin films deposited on glass substrates was studied by the AFM technique, and it was shown that the average diameter of all CdTe films increases with increasing laser energies. The mentioned properties were studied for the application of this thin film as the absorber layer in constructing a solar cell.

Optical Properties of Ferroelectric Thin Film Prepared by PLD Technique

Optical Properties of Ferroelectric Thin Film Prepared by PLD Technique

Predictive model of language deficit after removing glioma involving language areas under general anesthesia.

To establish a predictive model to predict the occurrence of language deficit for patients after surgery of glioma involving language areas (GILAs) under general anesthesia (GA). Patients with GILAs were retrospectively collected in our center between January 2009 and December 2020. Clinical variables (age, sex, aphasia quotient [AQ], seizures and KPS), tumor-related variables (recurrent tumor or not, volume, language cortices invaded or not, shortest distance to language areas [SDLA], supplementary motor area or premotor area [SMA/PMA] involved or not and WHO grade) and intraoperative multimodal techniques (used or not) were analyzed by univariate and multivariate analysis to identify their association with temporary or permanent language deficits (TLD/PLD). The predictive model was established according to the identified significant variables. Receiver operating characteristic (ROC) curve was used to assess the accuracy of the predictive model. Among 530 patients with GILAs, 498 patients and 441 patients were eligible to assess TLD and PLD respectively. The multimodal group had the higher EOR and rate of GTR than conventional group. The incidence of PLD was 13.4% in multimodal group, which was much lower than that (27.6%, P<0.001) in conventional group. Three factors were associated with TLD, including SDLA (OR=0.85, P<0.001), preoperative AQ (OR=1.04, P<0.001) and multimodal techniques used (OR=0.41, P<0.001). Four factors were associated with PLD, including SDLA (OR=0.83, P=0.001), SMA/PMA involved (OR=3.04, P=0.007), preoperative AQ (OR=1.03, P=0.002) and multimodal techniques used (OR=0.35, P<0.001). The optimal shortest distance thresholds in detecting the occurrence of TLD/PLD were 1.5 and 4mm respectively. The optimal AQ thresholds in detecting the occurrence of TLD/PLD were 52 and 61 respectively. The cutoff values of the predictive probability for TLD/PLD were 23.7% and 16.1%. The area under ROC curve of predictive models for TLD and PLD were 0.70 (95%CI: 0.65-0.75) and 0.72 (95%CI: 0.66-0.79) respectively. The use of multimodal techniques can reduce the risk of postoperative TLD/PLD after removing GILAs under general anesthesia. The established predictive model based on clinical variables can predict the probability of occurrence of TLD and PLD, and it had a moderate predictive accuracy.

V1−xWxO2 thermochromic films for device applications

V1−xWxO2 is known to be a reliable thermochromic material for multiple practical applications due to its insulator to metal transition temperature controlled by W dopping. In this paper, we present electrical and optical properties of V1−xWxO2 thin films synthesized by PLD technique. In this respect, the electrical resistance, the refractive index (n), and extinction coefficient (k) as a function of temperature from 25 to 80 °C and wavelength ranging from 500 to 3000 nm were obtained using conventional 4-probe resistance and ellipsometry methods. The direct and indirect bandgap values at different doping levels and temperatures have been calculated using n and k versus energy data and compared with thermally activated bandgap from electrical resistance. A decrease in direct and indirect bandgaps with temperature and wavelength was observed with doping and temperature. Comparison between thermal and optical bandgap demonstrates that activated thermal bandgap is only comparable with the lowest optical indirect bandgap.Graphical abstract

Crucial Role of Crystal Field on Determining the Evolution Process of Janus MoSSe Monolayer: A First-Principles Study.

Two-dimensional Janus MXY materials have been successfully synthesized from their parent species by CVD, SEAR, or PLD techniques. However, their detailed evolution process and underlying atomistic mechanism are far from understood conclusively, which are prompts for further research. Here, taking Janus MoSSe as a representation, the evolution process from MoS2 is systematically investigated by first-principles calculation. The simulation shows that the lowest formation energy of MoS(2-δ)Seδ increases with selenylation ratio δ. Unexpectedly, Se atoms prefer to form a pair in next-nearest neighboring state (Se-NN-Se), eventually transferred into a growth rule of (6n + 1) during the evolution process. Particularly, it is demonstrated that the stability of the intermediate is mainly governed by the Mo 4d orbitals in different distorted triangular crystal fields, rendering a different degree of orbital splitting. Both the occupied and unoccupied Mo 4d orbitals of Se-NN-Se are farther from the Fermi level than other cases, which is clearly illustrated by d-band center theory. These findings will be helpful to understand the evolution process and the underlying atomistic mechanism of Janus MXY.

Characterization of Superconductor Materials Doped with Nanoparticles on Their Properties: Review Article

Revolutionary developments have been started in the field of superconductors since their discovery. High-temperature superconductors have been a focus of attention in advanced technology for many scientists because of their potential applications. Therefore, many changes are made in the products that use such materials. It remains one of the most exciting research fields and can revolutionize the physics and technology of the future. It is required to understand and learn the history and basic principles of Superconductivity for its better implications. Considering its recent discoveries, its current applications can be studied. The mechanism of ‘HTS’ is much easier to understand after the significant development made in the field of Superconductivity. The purpose of this work is to better understand and appreciate research in the field of Superconductors. Basically, HTS has been used in many areas, but much progress is needed. HTS can be used in optoelectronics technologies and countless other applications after the effects seen by such improvements. In particular, this review focuses on the high-temperature BSCCO compound and its manufacture by the Solid-State reaction method and the PLD technique, which could be useful to electronics technology, particularly optoelectronic devices applications. Superconducting electronics devices have a lot of promise for future high-efficiency optoelectronics.

Role of coordination site in governing the structural, electronic and optical properties of Ca-doped strontium barium niobate

The structural, electronic and optical properties of Ca doped SBN60 are studied via first principle calculations based on density functional theory. Influence of Sr site substitution by Ca at square and pentagonal sites has been studied. The bandgap of Ca incorporated SBN is found to depend largely on the coordination of site of doping, where the bandgap increases for the square site substitution and decreases for the pentagonal site substitution. The formation energy calculations reveal that the Ca is more favorable to occupy the pentagonal site which is supported by the UV-Visible spectra study of the thin films of doped and undoped SBN60 grown using PLD technique in which a decrease in the bandgap can be seen in Ca doped SBN. A detailed analysis is provided for the changes in structural parameters upon doping at square and pentagonal sites. Dependence of the optical properties like dielectric constant, refractive index, reflectance and absorption of doped and undoped SBN60 on different polarization directions ‘(100), (010) and (001)’ are reported. The anisotropy in the optical properties can be observed which makes Ca doped SBN a promising material for optoelectronic device applications.