Showing papers on "Pulsed laser deposition published in 2003"
TL;DR: In this paper, a bottom-gate-type thin film transistors using ZnO as an active channel layer (ZnO-TFT) have been constructed using pulsed laser deposition at 450 °C at an oxygen pressure of 3 m Torr, and the material that was formed had a background carrier concentration of less than 5×1016 cm−3.
Abstract: Bottom-gate-type thin film transistors using ZnO as an active channel layer (ZnO–TFT) have been constructed. The ZnO layers were deposited using pulsed laser deposition at 450 °C at an oxygen pressure of 3 m Torr, and the material that was formed had a background carrier concentration of less than 5×1016 cm−3. A double layer gate insulator consisting of SiO2 and SiNx was effective in suppressing leakage current and enabling the ZnO–TFT to operate successfully. The Ion/Ioff ratio of ZnO–TFTs fabricated on Si wafers was more than 105 and the optical transmittance of ZnO–TFTs fabricated on glass was more than 80%. These results show that it is possible to fabricate a transparent TFT that can even be operated in the presence of visible light.
1,543 citations
TL;DR: In this paper, a review focusing on promising candidate materials (such as GaN, GaP and ZnO) is presented, where the introduction of Mn into these and other materials under the right conditions is found to produce ferromagnetism near or above room temperature.
Abstract: Recent advances in the theory and experimental realization of ferromagnetic semiconductors give hope that a new generation of microelectronic devices based on the spin degree of freedom of the electron can be developed. This review focuses primarily on promising candidate materials (such as GaN, GaP and ZnO) in which there is already a technology base and a fairly good understanding of the basic electrical and optical properties. The introduction of Mn into these and other materials under the right conditions is found to produce ferromagnetism near or above room temperature. There are a number of other potential dopant ions that could be employed (such as Fe, Ni, Co, Cr) as suggested by theory [see, for example, Sato and Katayama-Yoshida, Jpn. J. Appl. Phys., Part 2 39, L555 (2000)]. Growth of these ferromagnetic materials by thin film techniques, such as molecular beam epitaxy or pulsed laser deposition, provides excellent control of the dopant concentration and the ability to grow single-phase layers. T...
968 citations
TL;DR: In this article, a multistep pulsed-laser deposition (PLD) process is presented for epitaxial, nominally undoped ZnO thin films of total thickness of 1 to 2 μm on c-plane sapphire substrates.
Abstract: A multistep pulsed-laser deposition (PLD) process is presented for epitaxial, nominally undoped ZnO thin films of total thickness of 1 to 2 μm on c-plane sapphire substrates. We obtain reproducibly high electron mobilities from 115 up to 155 cm2/V s at 300 K in a narrow carrier concentration range from 2 to 5×1016 cm−3. The key issue of the multistep PLD process is the insertion of 30-nm-thin ZnO relaxation layers deposited at reduced substrate temperature. The high-mobility samples show atomically flat surface structure with grain size of about 0.5–1 μm, whereas the surfaces of low-mobility films consist of clearly resolved hexagonally faceted columnar grains of only 200-nm size, as shown by atomic force microscopy. Structurally optimized PLD ZnO thin films show narrow high-resolution x-ray diffraction peak widths of the ZnO(0002) ω- and 2Θ-scans as low as 151 and 43 arcsec, respectively, and narrow photoluminescence linewidths of donor-bound excitons of 1.7 meV at 2 K.
594 citations
TL;DR: In this article, a series of AZO films were grown on glass substrates by a method of pulsed laser deposition using a split target divided into AZO (Al2O3: 1 wt.%) and AZO(Al2 O3: 2 wt%).
404 citations
TL;DR: In this paper, thin films of Al-doped ZnO were grown on Al2O3 at high substrate temperature of 750°C by pulsed laser deposition technique with different Al concentrations.
Abstract: Thin films of Al-doped ZnO were grown on Al2O3 at high substrate temperature of 750 °C by pulsed laser deposition technique with different Al concentrations. Highly c-axis oriented and transparent (80%) thin films were obtained at 1 mTorr of O2 pressure. Increase of Al doping changes the stress in the ZnO films from tensile to compressive as measured from c-parameter. The XPS spectra indicated that the presence of hydroxides in the thin films. The surface morphology shows the decrease in surface roughness with Al doping. The maximum carrier concentration was found to be 4×1019 cm−3 with a mobility of 49 cm2 V−1 s−1 for 1% Al doping. However, the resistivity increased with increase in Al concentration. The bandgap was observed to increase with increase of Al doping and this may be attributed to Burstein–Moss shift and the stress in the films.
305 citations
TL;DR: In this article, a brief overview of thin film growth utilizing the reactive processes of chemical vapor deposition (CVD) and atomic layer deposition (ALD) is provided, with a focus on the latest advancements and future directions, and the processes and precursors commonly used to achieve controlled deposition.
Abstract: This article provides a brief overview of thin film growth utilizing the reactive processes of chemical vapor deposition (CVD) and atomic layer deposition (ALD). In CVD, thin films are deposited upon the chemical reaction of vapor phase precursors with a solid surface. ALD is a surface reaction-controlled variant of CVD in which the chemical precursors are introduced in a sequential, pulsed manner, resulting in the growth of a self-limited monolayer (or less) film for each pulse step. The aim of both methodologies is the controlled growth of thin films with desired and reproducible properties. Emphasis is given to the latest advancements and future directions, and the processes and precursors commonly used to achieve controlled deposition.
279 citations
TL;DR: In this article, low resistivity and highly transparent ZnO conducting films for thin-film solar cell applications were fabricated at low temperature by pulsed laser deposition, which achieved an average optical transmission of 91% for wavelengths between 400 and 1100 nm.
249 citations
TL;DR: The epitaxial growth of wideband gap cubic-phase MgxZn1−xO thin films on Si(100) by pulsed-laser deposition and fabrication of oxide-semiconductor-based ultraviolet photodetectors was reported in this article.
Abstract: We report on the epitaxial growth of wide-band-gap cubic-phase MgxZn1−xO thin films on Si(100) by pulsed-laser deposition and fabrication of oxide-semiconductor-based ultraviolet photodetectors. The challenges of large lattice and thermal expansion mismatch between Si and MgxZn1−xO have been overcome by using a thin SrTiO3 buffer layer. The heteroepitaxy of cubic-phase MgxZn1−xO on Si was established with epitaxial relationship of MgxZn1−xO(100)//SrTiO3(100)//Si(100) and MgxZn1−xO[100]//SrTiO3[100]//Si[110]. The minimum yield of the Rutherford backscattering ion channeling in MgxZn1−xO layer was only 4%, indicating good crystalline quality of the film. Smooth surface morphology with rms roughness of 0.6 nm was observed using atomic force microscopy. Photodetectors fabricated on Mg0.68Zn0.32O/SrTiO3/Si show peak photoresponse at 225 nm, which is in the deep UV region.
229 citations
TL;DR: In this paper, the microstructure and magnetic properties of cobalt substituted ZnO thin films deposited on sapphire (0001) substrates by pulsed laser deposition were investigated.
Abstract: We have investigated the microstructure and the magnetic properties of cobalt substituted ZnO thin films deposited on sapphire (0001) substrates by pulsed laser deposition. We have optimized the growth condition using in situ monitoring by reflection high-energy electron diffraction. We found that ferromagnetic films need to be grown at low oxygen partial pressure (<10−6 Torr). Films with 25% of Co are ferromagnetic at room temperature with clear out-of-plane anisotropy. We have looked for spurious origins of the ferromagnetic signal and found none.
228 citations
TL;DR: In this paper, an X-ray diffraction technique was used for analyzing microstructures of the indium zinc oxide (IZO) thin films, and also differential thermal analysis was performed for observing their crystallization behavior.
208 citations
TL;DR: In this paper, a single phase of perovskite BiFeO3 has been observed in thin films of 0.01-0.1 Torr at a temperature as low as 450°C by pulsed-laser deposition.
Abstract: Ferroelectric BiFeO3 thin films have been prepared on Pt/TiO2/SiO2/Si substrates in various oxygen pressures of 0.001–0.1 Torr at a temperature as low as 450 °C by pulsed-laser deposition. The crystallinity of the films was studied by x-ray diffraction. X-ray photoelectron spectroscopy showed that the films have a single phase of perovskite BiFeO3. The BiFeO3 thin films deposited at 0.01–0.1 Torr show good current-density–applied-voltage characteristics. It is obtained from polarization–electric-field characterization that 2Pr is about 71.3 μC/cm2 and 2Ec is 125 kV/cm. Stable current density and saturated ferroelectric hysteresis loop have been observed in BiFeO3 thin films.
TL;DR: In this article, two nanocrystalline Ni thin films, one prepared via DC magnetron sputtering and the other prepared via Pulsed laser deposition, were strained in-situ in the Transmission Electron Microscope.
TL;DR: In this paper, the synthesis of high-quality Co-doped ZnO thin films using the pulsed laser deposition technique on (0001)-Al2O3 substrates performed in an oxidizing atmosphere, using Zn and Co metallic targets.
Abstract: We report on the synthesis of high-quality Co-doped ZnO thin films using the pulsed laser deposition technique on (0001)-Al2O3 substrates performed in an oxidizing atmosphere, using Zn and Co metallic targets. We first optimized the growth of ZnO in order to obtain the less strained film. Highly crystallized Co:ZnO thin films are obtained by an alternative deposition from Zn and Co metal targets. This procedure allows an homogenous repartition of the Co in the ZnO wurzite structure which is confirmed by the linear dependence of the out-of-plane lattice parameter as a function of the Co dopant. In the case of 5% Co doped, the film exhibits ferromagnetism with a Curie temperature close to the room temperature.
TL;DR: In this article, Li-doped ZnO with different compositions (Zn1-xLixOy, x=0.075, 0.125 and 0.15) have been prepared on heavily doped Si substrates by a pulsed laser deposition technique.
Abstract: Zinc oxide is a very important piezoelectric material with lower preparation temperature, simpler structure and composition. By doping with some elements having smaller ionic radii, such as lithium, to substitute the zinc ions, it is expected that the center of the positive charge in a unit cell will not overlap with that of the negative charge in the same unit cell, leading to the appearance of the spontaneous polarization. Thin films of Li-doped ZnO with different compositions (Zn1-xLixOy, x=0.075, 0.1, 0.125 and 0.15) have been prepared on heavily doped Si substrates by a pulsed laser deposition technique. In the films with x=0.1 and x=0.125, ferroelectric P–E hysteresis loops were successfully observed. The remanent polarization and the coercive field of Zn0.9Li0.1Oy and Zn0.875Li0.125Oy were (0.193 μC/cm2, 4.8 kV/cm) and (0.255 μC/cm2, 4.89 kV/cm), respectively. An anomalous point in the dielectric spectrum of the Li-doped ZnO ceramics is observed, showing that the ferroelectric phase transition occurs around 67 °C under 7.5 at. % Li-doped ZnO and 74 °C under 10 at. %. If the remanent polarization of this material can be further increased, it may be used as a ferroelectric material.
TL;DR: Physical vapor deposition (PVD) of thin films relies on the removal of atoms from a solid or a liquid by energetic means, and the subsequent deposition of those atoms on a nearby surface as mentioned in this paper.
Abstract: The properties of thin films depend critically on how they are made. For the most part, thin films are assembled in ways very different from the production of bulk materials. Thin films are usually deposited on existing, bulk surfaces using techniques based on atomic or molecular scale physics and chemistry. Physical vapor deposition (PVD) of thin films relies on the removal of atoms from a solid or a liquid by energetic means, and the subsequent deposition of those atoms on a nearby surface. Variations of PVD processes include thermal evaporation, physical sputtering, laser ablation, and arc-based emission. Additional modifications to physical sputter deposition have been made to enhance the chemical and/or structural nature of the deposited films. These modifications include reactive sputter deposition, the unbalanced magnetron, collimated and ionized sputter deposition. Each of these systems and techniques will be described as well as some of the current day applications of the films produced.
TL;DR: In this article, the synthesis of high-quality Co-doped ZnO thin films using the pulsed laser deposition technique on (0001)-Al$_2$O$_3$ substrates performed in an oxidizing atmosphere, using Zn and Co metallic targets.
Abstract: We report on the synthesis of high-quality Co-doped ZnO thin films using the pulsed laser deposition technique on (0001)-Al$_2$O$_3$ substrates performed in an oxidizing atmosphere, using Zn and Co metallic targets. We firstly optimized the growth of ZnO in order to obtain the less strained film. Highly crystallized Co:ZnO thin films are obtained by an alternative deposition from Zn and Co metal targets. This procedure allows an homogenous repartition of the Co in the ZnO wurzite structure which is confirmed by the linear dependance of the out-of-plane lattice parameter as a function of the Co dopant. In the case of 5% Co doped, the film exhibits ferromagnetism with a Curie temperature close to the room temperature.
TL;DR: In this paper, an epitaxial (001)-, (118)-, and (104)-oriented Nd-doped Bi4Ti3O12 films have been grown by pulsed-laser deposition from a Bi4−xNdxTi3 O12 (x=0.85) target on SrRuO3 coated single-crystal (100-, (110)- and (111)-oriented substrates, respectively.
Abstract: Epitaxial (001)-, (118)-, and (104)-oriented Nd-doped Bi4Ti3O12 films have been grown by pulsed-laser deposition from a Bi4−xNdxTi3O12 (x=0.85) target on SrRuO3 coated single-crystal (100)-, (110)-, and (111)-oriented SrTiO3 substrates, respectively. X-ray diffraction illustrated a unique epitaxial relationship between film and substrate for all orientations. We observed a strong dependence of ferroelectric properties on the film orientation, with no ferroelectric activity in an (001)-oriented film; a remanent polarization 2Pr of 12 μC/cm2 and coercive field Ec of 120 kV/cm in a (118)-oriented film; and 2Pr=40 μC/cm2, Ec=50 kV/cm in a (104)-oriented film. The lack of ferroelectric activity along the c-axis is consistent with the orthorhombic nature of the crystal structure of the bulk material, as determined by powder neutron diffraction.
TL;DR: The doping behavior of phosphorus in ZnO thin films grown by pulsed laser deposition is examined in this article, showing that the phosphorus-related donor defect is relatively unstable and suggests the formation of a deep level upon annealing.
Abstract: The doping behavior of phosphorus in ZnO thin films grown by pulsed laser deposition is examined. The transport properties of epitaxial ZnO films doped with 1–5 at. % P were characterized via room temperature Hall measurements. As-deposited films doped with phosphorus are highly conductive and n type. The origin of the shallow donor level appears to be either substitution of P on the Zn site or formation of a donor complex. Annealing these phosphorus-doped films significantly reduces the carrier density, transforming the transport from highly conducting to semi-insulating. These results indicate that the phosphorus-related donor defect is relatively unstable, and suggests the formation of a deep level upon annealing. The latter is consistent with phosphorus substitution on the O site yielding a deep level in the gap.
TL;DR: In this article, a transparent p-n junction composed of zinc oxide, copper-aluminum oxide and indium-tin oxide films was fabricated by pulsed laser deposition on glass substrates at temperatures as low as 400 °C.
TL;DR: In this paper, a pulsed-laser deposition on a LaAlO3 substrate with (La0.7Sr0.3)MnO3 as the bottom electrode was performed to obtain a high dielectric permittivity and temperature characteristic.
Abstract: Compositionally graded barium strontium titanate [(BaxSr1−x)TiO3—BST, x=0.75, 0.8, 0.9, and 1.0] thin films are fabricated by pulsed-laser deposition on a LaAlO3 substrate with (La0.7Sr0.3)MnO3 as the bottom electrode. A high dielectric permittivity and temperature characteristic without Curie–Weiss law are obtained. A tunability of over 70% is obtained at frequency of 1 MHz, which is higher than that of single BST layer with the same compositions. All the results indicate that the graded thin films have better electrical properties than a single-layer film.
TL;DR: The matrix-assisted pulsed laser evaporation (MAPLE) and MAPLE direct write (MDW) techniques as mentioned in this paper have been used to transfer biomaterials using a pulsed beam.
Abstract: Two techniques for transferring biomaterial using a pulsed laser beam were developed: matrix-assisted pulsed laser evaporation (MAPLE) and MAPLE direct write (MDW). MAPLE is a large-area vacuum based technique suitable for coatings, i.e., antibiofouling, and MDW is a localized deposition technique capable of fast prototyping of devices, i.e., protein or tissue arrays. Both techniques have demonstrated the capability of transferring large (mol wt>100 kDa) molecules in different forms, e.g., liquid and gel, and preserving their functions. They can deposit patterned films with spatial accuracy and resolution of tens of μm and layering on a variety of substrate materials and geometries. MDW can dispense volumes less than 100 pl, transfer solid tissues, fabricate a complete device, and is computed aided design/computer aided manufacturing compatible. They are noncontact techniques and can be integrated with other sterile processes. These attributes are substantiated by films and arrays of biomaterials, e.g., polymers, enzymes, proteins, eucaryotic cells, and tissue, and a dopamine sensor. These examples, the instrumentation, basic mechanisms, a comparison with other techniques, and future developments are discussed.
TL;DR: In this article, the epitaxial CeO2 buffer layers were grown on biaxially textured Ni-W substrates for YBCO coated conductors using a newly developed metal organic decomposition (MOD) approach.
Abstract: We have grown epitaxial CeO2 buffer layers on biaxially textured Ni–W substrates for YBCO coated conductors using a newly developed metal organic decomposition (MOD) approach. Precursor solution of 0.25 M concentration was spin coated on short samples of Ni–3 at%W (Ni–W) substrates and heat-treated at 1100 °C in a gas mixture of Ar–4%H2 for 15 min. Detailed x-ray studies indicate that CeO2 films have good out-of-plane and in-plane textures with full-width-half-maximum values of 5.8° and 7.5°, respectively. High temperature in situ XRD studies show that the nucleation of CeO2 films starts at 600 °C and the growth completes within 5 min when heated at 1100 °C. SEM and AFM investigations of CeO2 films reveal a fairly dense microstructure without cracks and porosity. Highly textured YSZ barrier layers and CeO2 cap layers were deposited on MOD CeO2-buffered Ni–W substrates using rf-magnetron sputtering. Pulsed laser deposition (PLD) was used to grow YBCO films on these substrates. A critical current, Jc, of about 1.5 MA cm−2 at 77 K and self-field was obtained on YBCO (PLD)/CeO2 (sputtered)/YSZ (sputtered)/CeO2 (spin-coated)/Ni–W.
TL;DR: In this article, a consistent set of epitaxial, n-type conducting ZnO thin films, nominally undoped, doped with Ga or Al, or alloyed with Mg or Cd, was grown by pulsed laser deposition (PLD) on single-crystalline c-plane sapphire (0, 0,0,1) substrates, and characterized by Hall measurement, and UV/VIS optical transmission spectroscopy.
Abstract: A consistent set of epitaxial, n-type conducting ZnO thin films, nominally undoped, doped with Ga or Al, or alloyed with Mg or Cd, was grown by pulsed laser deposition (PLD) on single-crystalline c-plane sapphire (0 0 0 1) substrates, and characterized by Hall measurement, and UV/VIS optical transmission spectroscopy. The optical band gap of undoped ZnO films at nearly 3.28 eV was shifted by alloying with Mg up to 4.5 eV and by alloying with Cd down to 3.18 eV, dependent on the alloy composition. In addition, highly doped ZnO:Al films show a blue-shifted optical absorption edge due to filling of electronic states in the conduction band. The Hall transport data of the PLD (Mg,Zn,Cd)O:(Ga,Al) thin films span a carrier concentration range of six orders of magnitude from 3 × 1014 to 3 × 1020 cm−3, which corresponds to a resistivity from 5 × 10−4 to 3 × 103 Ω cm. Structurally optimized, nominally undoped ZnO films grown with ZnO nucleation and top layer reached an electron mobility of 155 cm2/V s (300 K), which is among the largest values reported for heteroepitaxial ZnO thin films so far. Finally, we succeeded in combining the low resistivity of ZnO:Ga and the band gap shift of MgZnO in MgZnO:Ga thin films. This results demonstrate the unique tunability of the optical and electrical properties of the ZnO-based wide-band gap material for future electronic devices.
TL;DR: In this paper, the initial crystalline structure of the target is reconstructed after 1 h films annealing at 550 °C in ambient air, both at room temperature and after that annealed at this temperature.
Abstract: Hydroxyapatite (HA) thin films for applications in bone prosthesis fabrication were obtained by the radio-frequency magnetron sputtering technique. The depositions were performed from pure HA targets on Si and Ti–5Al–2.5Fe alloy substrates. In some experiments a buffer layer of TiN was introduced by pulsed laser deposition before HA coating. The films were deposited in low-pressure argon or Ar–O2 mixtures at substrate temperatures ranging from 70 to 550 °C. We observed that the films grown at temperatures below 300 °C were prevalently amorphous and contain a small amount of crystalline material. The initial crystalline structure of the target is reconstructed after 1 h films annealing at 550 °C in ambient air. Both the films directly deposited at 550 °C and the ones obtained at room temperature and after that annealed at this temperature—mostly contain the HA phase and exhibit good mechanical characteristics. Weaker peaks of CaO secondary phase are visible in the X-ray diffraction patterns of the films directly grown at 550 °C. Traces of TiO2 were detected at the interface with the metallic substrate in case of structures grown without the TiN interlayer. All films were smooth, with an average surface roughness of 50 nm. The films grown on TiN interlayer are harder, have higher elasticity modulus values and an increased mechanical resistance at the indenter penetration.
TL;DR: In this paper, high-oriented Ga-doped ZnO nanorod arrays have been fabricated on GaN and sapphire substrates by pulsed laser deposition and X-ray diffraction shows that these nanorods are grown epitaxially with the c-axis normal to the substrate.
Abstract: Highly oriented Ga-doped ZnO nanorod arrays have been fabricated on GaN and sapphire substrates by pulsed laser deposition. X-ray diffraction shows that these nanorods are grown epitaxially with the c-axis normal to the substrate. The ZnO nanorod formation proceeds as follows. After a wetting layer of ZnO film grows to approximately 14 nm in thickness, the Stranski–Krastanov instability takes place due to interface strain. As a result, ZnO nanodots are formed uniformly on the ZnO layer. These nanodots then serve as nucleation sites for the subsequent electric-field-assisted growth of nanorods. Ga-doping level plays a key role in the formation of ZnO nanorods, while the oxygen partial pressure and the substrate temperature also affect the morphology of nanorods. These self-assembled and ordered ZnO nanorod arrays may be used in field emission and optoelectronic applications.
TL;DR: Amorphous LaAlO3 (LAO) and LAOxNy (LAON) films have been prepared by pulsed laser deposition technique on Si (100) substrates and Pt coated silicon substrates as discussed by the authors.
Abstract: Amorphous LaAlO3 (LAO) and LAOxNy (LAON) films have been prepared by pulsed laser deposition technique on Si (100) substrates and Pt coated silicon substrates. X-ray diffraction, transmission electron microscopy and differential thermal analysis investigations showed that both kinds of films remain amorphous up to a high temperature of 860 °C. Atomic force microscopy study indicated that the surface of the deposited films is very smooth with a root mean square roughness of 0.14 nm for 8 nm LAO. LAON films have a smoother surface than that of LAO films. High-resolution transmission electron microscope studies showed there often exists interfacial reaction between LAO and Si. One LAON/Si structure nearly without interfacial layer has been obtained. For LAO films, high bandgap of 6.55 eV and medium dielectric constant of 25–27 have been obtained. The LAON films showed small equivalent oxide thickness of 1.1 nm with a low leakage of 0.074 A/cm2@Vg=+1 V. It is proposed that amorphous LAON films are very promis...
TL;DR: In this article, the authors performed x-ray diffraction and Raman spectroscopy measurements in the temperature range of 300-873 K on a single phase epitaxially oriented BaTiO3 thin film grown by pulsed laser deposition on a one crystal MgO substrate.
Abstract: We have performed x-ray diffraction and Raman spectroscopy measurements in the temperature range of 300–873 K on a single phase epitaxially oriented BaTiO3 thin film grown by pulsed laser deposition on a single crystal MgO substrate. The θ–2θ room temperature diffraction measurements and asymmetric rocking curves indicate that the film is very weakly tetragonal with the c-axis parallel to the plane of the film. X-ray diffraction measurements up to high temperature reveal only a change in slope in the perpendicular to the plane lattice parameter around 450 K (in bulk Tc=395 K) indicating that a diffuse-like of phase transition is taking place. Room temperature polarized Raman spectra show that the film is indeed tetragonal with C4v symmetry and with the a-axis perpendicular to the film plane. Monitoring of the overdamped soft mode and the 308 cm−1 mode confirms that the phase transition is taking place over a wide temperature range according to the x-ray results. The increase of the phase transition temper...
TL;DR: In this article, the effect of post-annealing treatment on the optical properties of ZnO thin films was investigated for the application of light emission device, and the structural, electrical and optical properties were investigated.
Abstract: ZnO thin films on (001) sapphire substrates have been deposited by pulsed laser deposition (PLD). In order to investigate the effect of post-annealing treatment on the optical property of ZnO thin films, films have been annealed in oxygen at various annealing temperatures after deposition. After post-annealing treatment in the oxygen ambient, the optical properties of ZnO thin films were characterized by photoluminescence (PL). The structural properties of ZnO thin films were characterized by XRD. Crystallinity of ZnO film is enhanced at annealing temperature above 700 °C. As the post-annealing temperature increases, intensity of UV (380 nm) peak is decreased while the intensity of visible (about 490–530 nm) peak is increased, carrier concentration is decreased and resistivity was increased. Structural, electrical and optical properties of ZnO films have been investigated for the application of light emission device.
TL;DR: In this paper, nanorods with a size of approximately 300 nm in average diameter and 6 µm in length were grown on sapphire substrates heated at approximately 700°C by the pulsed-laser deposition technique without any catalyst.
Abstract: Nano-structured ZnO thin films were synthesized by the nanoparticle assisted pulsed-laser deposition in an oxygen background gas. Crystallized and c-axis oriented ZnO nanorods with a size of approximately 300 nm in average diameter and 6 µm in length were grown on sapphire substrates heated at approximately 700°C by the pulsed-laser deposition technique without any catalyst. Strong photoluminescence near the band-gap was observed from nanorods under excitation at 308 nm. The Rayleigh scattering diagnostics of the plume was also conducted, revealing that the nanorods grew from ZnO nanoparticles which formed in the plume and were transported onto the substrate.
TL;DR: Micro- and nano-testing methods have been explored to study the thin calcium phosphate coatings with high adhesive strength and showed that the crystalline HA coating is superior in internal cohesion to the amorphous one, even though the lower elastic modulus of amorphously coating could be more mechanically compatible with natural bone.