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Anion doping is an efficient method for modifying the electrical property of the p‐type semiconductor CuI. However, adjustment of the hole density is still challenging. Using sputtering and spin coating techniques, well‐controlled S‐doping of CuI thin films has been realized. The spin‐coated samples present a single (111) out‐of‐plane orientation and very high crystallinity, which is comparable with previously reported epitaxial CuI thin films. The sputtered thin films have advantages in surface morphology and conductivity. Substituting S for I can achieve efficient acceptor doping of CuI for both the physical and chemical growth methods. The highest conductivity of CuI appears at 2.0 at% of S doping, and the doping efficiency is influenced by the self‐compensation effect. [ABSTRACT FROM AUTHOR]

The article in Advanced Energy Materials explores the impact of dimethyl sulfoxide (DMSO) intercalation in the iodoplumbate(DMSO)x complex on the orientation of perovskite crystal planes in thin-film solar cells. Researchers found that achieving uniaxially oriented crystal growth at an optimal DMSO intercalation level led to enhanced performance in the solar cells compared to those with isotropic perovskite crystals. The study highlights the importance of regulating the deposition temperature of the iodoplumbate(DMSO)x colloid to control crystal orientation. [Extracted from the article]

A comparative study of the synthesis of TiO2 nanorods on fluorine‐doped tin oxide (FTO) glass, Si, SiO2, Si/Ta, Si/TiN, Si/TiN/Ti and Si/HFO2 substrates by hydrothermal reaction is presented. Detailed analysis on the growth of TiO2 on pre‐annealed Si/TiN/Ti and HfO2 (HFO) surfaces is also given. For Si/TiN/Ti, a pre‐annealing procedure led to the transformation of Ti to a TiO2 layer which acts as a seed for aligned growth of TiO2 nanorods. In contrast, Si/HFO does not provide a nucleation site for the formation of aligned nanorods. Various samples were prepared by varying the synthesis conditions, i.e. pre‐ and post‐annealing temperatures and hydrothermal reaction time to figure out the optimum conditions which lead to unidirectional and highly aligned nanorods. X‐ray diffraction, scanning electron microscopy, ultraviolet–visible spectroscopy and Raman spectroscopy were used to study structural, morphological and optical properties of synthesized samples. It is found that TiO2 nanorods exhibit a rutile phase on the Si/Ti/TiN and Si/HFO substrates, but highly oriented vertical growth of nanorods has been observed only on pre‐annealed Si/TiN/Ti substrates. On the other hand, TiO2 nanorods form dandelion‐like structures on Si/HFO substrates. Growth of vertically oriented TiO2 nanorods on Si/TiN/Ti is attributed to the TiO2 seed layer which forms after the process of pre‐annealing of substrates at a suitable temperature. Variation in hydrothermal reaction time and post‐annealing temperature brings further improvement in crystallinity and morphology of nanorods. This work shows that the pre‐annealed Si/TiN/Ti substrate is the optimal choice to achieve vertically oriented, highly aligned TiO2 nanorods. [ABSTRACT FROM AUTHOR]

Highly (001)‐oriented pure‐phase BFO films were prepared on traditional Si substrates via radio frequency magnetron sputtering (RFMS). The crystallinity of the films is found to be increased, that is, higher degree of (001) texture, larger grain size, less grain boundary, denser surface morphology, and better thickness uniformity, with increased film thickness. These factors have significant influences on the electrical properties of BFO films, that is, dielectric response, as well as ferroelectric polarization and leakage current characteristics. The 240‐nm‐thick film exhibits relatively poor electrical properties compared with other three thicker films, which is mainly due to its small grain, the enhancement of the clamping effect of neighboring grains, and the absence of domain walls. The essential roles of the evolution and distribution of grains/domains and defect charges in leakage mechanism and ferroelectric switching polarization were also investigated systematically. It was found that 600‐nm‐thick BFO film has the lowest leakage current density (as low as 1.8 × 10−6 A / cm2 @ 90 kV/cm) and followed a mixed SE or SCLC conduction behavior, while the leakage behavior in other films is dominated by SE and P‐F currents. All (001)‐BFO films have a giant electrical polarization which is solely originated from the contribution of ferroelectric domain switching, and it has lower switching voltage and faster switching rate in thicker films. [ABSTRACT FROM AUTHOR]

The potential of metal–organic frameworks (MOFs) for applications in optoelectronics results from a unique combination of interesting photophysical properties and straightforward tunability of organic and inorganic units. Here, it is demonstrated that using MOF approach chromophores can be assembled into well‐ordered 1D arrays using metal‐oxo strands as lead structure, and the resulting porphyrinic rows exhibit unique photophysical properties and allow the realization of highly sensitive photodetectors. A porphyrinic MOF thin film, In‐TCPP surface‐coordinated MOF thin films with [021] orientation is fabricated using a layer‐by‐layer method, from In(NO3)3 and TCPP (5,10,15,20‐(4‐carboxyphenyl)porphyrin). Detailed experimental and theoretical analysis reveals that the assembly yields a structure where In‐oxo strands running parallel to the substrate fix the chromophoric linkers to yield 1D arrays of porphyrins. The frontier orbitals of this highly anisotropic arrangement are localized in these columnar arrangements of porphyrins and result in high photoactivity, which is exploited to fabricate a photodetector with record (as compared to other organic materials) responsivity in visible regime of 7.28 × 1014 Jones and short rise/fall times (0.07/0.04 s). This oriented MOF thin film‐based high‐sensitive photodetector provides a new avenue to use inorganic, stable lead structures to assemble organic semiconductors into regular arrays, thus creating a huge potential for the fabrication of optoelectronic devices. [ABSTRACT FROM AUTHOR]

Assembly of metal-organic framework (MOF) thin-films with well-ordered growth directions enables many practical applications and is likely part of the future of functional nanomaterials. Insights into the formation pathway of the MOF thin films would allow better control over the growth directions and possibly the amount of guest molecules absorbed into the MOF pores. Here, we investigate the nucleation and growth of oriented Cu 3 (BTC) 2 ∙xH 2 O MOF (HKUST-1, BTC = benzene-1,3,5-tricarboxylic acid) thin films on the thermal SiO 2 surface using a room temperature stepwise layer-by-layer (LBL) method. Initial stages of LBL growth were characterized with X-ray photoelectron spectroscopy and high-resolution transmission electron microscopy analysis in order to understand nucleation and growth kinetics. HKUST-1 thin films with preferred growth along the [111] direction on the thermal SiO 2 surface were obtained in the absence of not only a gold substrate, but also organic-based self-assembled monolayers (SAMs). It is found that the formation of HKUST-1 is initiated by deposition of copper acetate on the thermal SiO 2 surface followed by ligand exchange between coordinated acetate from the copper precursor and the BTC ligands. As the LBL growth cycle is increased, HKUST-1 crystals on the thermal SiO 2 surfaces are continuously forming and growing and finally the crystallites coalesce into a continuous film. Highly oriented HKUST-1 thin films on thermal SiO 2 surface with complete surface coverage and ~90 nm thickness were obtained at ~80 cycles of LBL growth under the conditions used in this study. [ABSTRACT FROM AUTHOR]

Thin films of M Fe 2 O 4 ( M = Co, Mg, Cu) were prepared on platinum coated silicon wafers by spin coating of solutions of the metal nitrates in N , N -dimethylformamide and acetic acid with subsequent heating at different temperatures. X-ray diffraction and Raman spectroscopy revealed the formation of phase-pure spinel ferrites. For medium synthesis temperatures, scanning electron microscopy and atomic-force microscopy investigations reveal smooth and uniform surfaces with root mean square roughness values in the nm range for all ferrites. Heating at higher temperatures leads to an increase of the grain sizes and in turn to higher surface roughnesses. For CoFe 2 O 4 and CuFe 2 O 4 the grains show a columnar growth perpendicular to the substrate surface, while the MgFe 2 O 4 grains grow plate-like parallel to it. Rocking curve measurements revealed a highly oriented growth for all three ferrites above a specific synthesis temperature with the (111) lattice plane being parallel to the film surface. This orientation and the mosaicity of the ferrite films are induced by the underlying Pt-layer. Magnetic properties were measured with H perpendicular and parallel to the film surface. We observed a magnetic anisotropy for the three ferrites, where the easy axis is perpendicular to the film surface for the CoFe 2 O 4 films and parallel in the case of MgFe 2 O 4 and CuFe 2 O 4 . For the CoFe 2 O 4 films a reorientation of the magnetic easy axis in the [111] direction and a very strong anisotropy was found with the remanent magnetization perpendicular to the film surface being about twice as large as parallel to it. [ABSTRACT FROM AUTHOR]

We demonstrated the high-speed laser chemical vapor deposition of orthorhombic NaTaO 3 (o-NaTaO 3 ) films. The orientation of the o-NaTaO 3 films was changed from (101) to (112) to (001) plane as the increase of deposition temperature from 823 to 913 K. o-NaTaO 3 films had faceted surfaces and columnar cross sections. The deposition rates of o-NaTaO 3 films were 48–120 µm h −1 , which are 192–6000 times higher than those offered by wet-chemical routes. [ABSTRACT FROM AUTHOR]

We report on highly oriented growth of VO 2 (B) thin films on Mo foils by reactive sputtering and its performance as an cathode electrode material in lithium ion batteries. Reactively sputtered films under moderate O 2 flow and substrate temperature revealed (001)-oriented growth on the poly-crystalline Mo foils with electrically floating potential. It can be interpreted that the oriented VO 2 (B) film can grow on Mo substrates under narrow condition in which ions with restricted energies result in crystalline lattice formation with moderate substrate temperature. The lithium ion battery utilizing the VO 2 (B) film on Mo foil as cathode electrode revealed specific capacity of 110 mAhg − 1 at 2.0 V. Repeated charge/discharge experiments indicated that the oriented VO 2 (B) film, in which VO 6 octahedra pile up with vacant cites of O atoms orderly that can act as spaces for Li intercalation and de-intercalation, has certain potential as cathode material. [ABSTRACT FROM AUTHOR]

Thin films of SrAl 12 O 19 were prepared on α-Al 2 O 3 (0001) substrates through the chemical solution deposition method and thermal treatment. Two types of precursor systems were used: stoichiometric mixture of strontium methoxyethoxide with aluminium iso-butoxide, and strontium methoxyethoxide topotactically reacting with Al 2 O 3 substrate. Two distinctly different film-substrate orientation relationships were observed. In the latter case the orientation can described as perfect hexagon-on-hexagon epitaxy with 11 2 − 0 SrAl12O19 || 10 1 − 0 Al2O3 and (0001) Al2O3 || (0001) SrAl12O19 . This relationship has 1.17% lattice misfit in the substrate plane. In the former case SrAl 12 O 19 grains are rotated about the substrate normal and form more orientation variants that can be explained by the coincident-site lattice model for grain boundaries. We demonstrated that both types of SrAl 12 O 19 films can be used as a chemical buffer and structural template layer for the growth of oriented hexagonal ferrite thin films. In both types of films the (BaSr)Fe 12 O 19 phase cope the in-plane orientation of their respective templates. [ABSTRACT FROM AUTHOR]

The formation and structural characterization of highly (111)-oriented Co 3 O 4 and CoFe 2 O 4 films prepared by a novel procedure from 00l-oriented NaCoO 2 and Na(CoFe)O 2 is reported. The Na(CoFe)O 2 films were deposited on MgO, SrTiO 3 , LaAlO 3 , and Zr(Y)O 2 single crystals with (100) and (111) orientations by chemical solution deposition method and crystallized at 700 °C. Subsequently they were transformed into (111)-oriented spinel phase during post-growth annealing at 800–1000 °C. Morphology and structure of the films was investigated by means of scanning electron microscopy and X-ray diffraction. While all spinel films exhibit pronounced out-of-plane orientation irrespective of substrate, the rate of in-plane orientation strongly depend on lattice misfit values. Different epitaxial phenomena ranging from true one-to-one epitaxy to the existence of many-to-one epitaxy involving two or more orientations were determined by full 3D texture analysis. [ABSTRACT FROM AUTHOR]

The influence of external magnetic field on the morphology of α-Fe 2 O 3 thin film formed at liquid–vapor interface has been investigated. Application of magnetic field during the growth of film resulted in the magnetic moment ordering of constituent nanoparticles. Thus formed α-Fe 2 O 3 thin film was transferred to a glass substrate, which upon annealing converted into one dimensional (1D) nanostructured thin film due to the oriented attachment of magnetically ordered nanoparticles. The effect of dopants viz. Ni 2 + and Co 2 + on the directional growth, and magnetic properties of nanostructures has also been investigated. The Ni 2 + and Co 2 + doped α-Fe 2 O 3 1D nanostructured thin films show superparamagnetic and ferromagnetic behavior, respectively, whereas undoped α-Fe 2 O 3 film exhibits superparamagnetism. From the room temperature magnetization measurements of films, it is found that the magnetization depends upon the morphology and magneto-crystalline anisotropy attributes of the film nanostructures. [ABSTRACT FROM AUTHOR]

Abstract: Ba β-alumina films were prepared by laser chemical vapor deposition. Mostly single-phase Ba β-alumina films were obtained at 1125–1200K and for an Al/Ba molar ratio of 12.4–16.6. BaAl2O4 and α-Al2O3 were codeposited with Ba β-alumina under Ba- and Al-rich conditions, respectively. The Ba β-alumina films consisted of hexagonal grains, and the (110)-oriented Ba β-alumina films had a fin-like columnar structure. The highest deposition rate reached 120μmh−1 at around 1200K. A thin layer of Ba-rich superstructure was formed on the surface of the (110)-oriented columnar grains. [Copyright &y& Elsevier]

Abstract: Oriented thermoelectric (TE) p-Sb2Te3 and n-Bi2Te3 thin films with special nanostructures have been synthesized by a simple vacuum thermal evaporation technique. The composition and microstructure of the films were studied by X-ray diffraction (XRD) and scanning electron microscopy (SEM), presenting a well preferential crystal growth with dense slender columnar grains grown perpendicular to the substrate, and energy dispersive X-ray spectrum (EDX) indicating the compositions distribution in the films. The electric transport properties, i.e., conductivity and Seebeck coefficient, and the thermal transportation of the oriented films show optimized properties. Prototype devices were built up by p and n elements in series and parallel circuits. The largest output power and cooling could be achieved in Sb2Te3 parallel device with P max =6.51μW at ΔT =106K, and cooling of 4.1K at 2V. The 24-pair p–n couples series device could output maximum voltage of 313mV at ΔT =102K. The power generation and the cooling of the devices show times enhanced TE performances than those consisting of common films. The results proved that introducing nanostructures into films is an effective choice to obtain high-efficient micro TE device. [Copyright &y& Elsevier]

Abstract: Keggin heteropolyacid incorporated Cu3(BTC)2 (BTC=1,3,5-benzenetricarboxylic acid) thin films were grown on metallic Cu substrates in various solvents at ambient conditions. The Keggin heteropolyacid templated the growth of Cu3(BTC)2 crystals while the Cu substrate served as Cu2+-ion source. To obtain smooth, homogeneous films the optimal growth conditions found were in an ethanolic solution in contact with ambient air. X-ray diffraction measurements showed a preferred (100) orientation of the Cu3(BTC)2 crystals in ethanol while the use of a water-based solvent yielded a dominating (111) orientation. [Copyright &y& Elsevier]

Abstract: CdS thin films on LiNbO3 (104) and silicon (111) substrates were prepared through an atom substitution technique using cadmium nitrate as a reactant in an H2S atmosphere at 230°C. X−ray diffraction, scanning electron microscopy and transmission microscopy results indicate that the CdS film grows on LiNbO3 oriented along the [001] axis in form of crystallized nanoplates, while that deposited on silicon forms randomly oriented nanoparticles. Investigation of the precursor thin film suggests that CdS forms from the O in the CdO precursor thin film being substituted by S from H2S in the surrounding environment, which is designated as an atom substitution process. This novel method involving an atom substitution reaction between the CdO precursor thin film and its environment can provide a new low cost approach to the preparation of chalcogenide or other compound thin films. A schematic illustration and corresponding mechanism describing the details of this method are proposed. [Copyright &y& Elsevier]

The magnetic nanoparticles of Fe/FeCo/FePt, in the past, in a PLD system were grown by us using argon ambient gas pressure of about 0.1-75.0 mbar, as the ambient gas pressure can be used to tune the energy of the incident plasma plume species, the expansion volume, the growth duration, etc. which can control the particle size. In present paper, we report the direct synthesis of small-sized nanoparticles even when no ambient gas was used, with the experiments being done in higher vacuum of about 10 mbar in PLD chamber. The deposition rate under vacuum condition is significantly higher than the deposition rate at high ambient pressure. The study of inplane and outplane magnetic properties, along with XRD results, confirmed that the as-deposited CoPt nanoparticles thin film has oriented growth. The as-deposited CoPt nanoparticles are in magnetically soft fcc phase and a post deposition annealing at 600°C resulted in phase transition to magnetically hard fct phase. [ABSTRACT FROM AUTHOR]

Abstract: A simple electrochemical process has been demonstrated to grow highly oriented γ-CuI thin films on indium doped tin oxide (ITO) glass through reducing Cu(II)–ethylene diamine tetraacetic acid disodium (EDTA) complex in aqueous solutions at or near room temperature. The CuI thin films grow preferential orientation along the 〈111〉 crystal axis from the X-ray diffraction patterns. The oriented growth of the CuI thin films is not affected by the solution pH and the applied potentials. The possible mechanism of the oriented growth is discussed, and the surface energy of different crystal planes of CuI crystal is believed to play an important role to control the oriented growth of the CuI thin films. The bandgap of the electrodeposited CuI films is 2.98eV and the photoluminescence spectra of the CuI thin films exhibit relative intense exciton band luminescence at room temperature. [ABSTRACT FROM AUTHOR]

SrMoO4 films have been prepared via chemical solution processing. Ethylene glycol, 1, 2-propylene glycol and glycerol were chosen as solvents. The effects of solvents on the microstructures and morphologies are investigated. X-ray diffraction, atom force microscope and scanning electron microscope have been employed to characterize microstructures and morphologies of the films. The results show that films deriving from different solvents are crystallized near room temperature (40∼60°C). And they have different growth characteristic after annealing. It is found that the number and space configuration of hydroxyl play important roles on the growth characteristic of the films. And when, the SrMoO4 film derived from glycerol solvents display an oriented growth along a-axis. [ABSTRACT FROM AUTHOR]

Abstract: Highly (100)-oriented LaNiO3 (LNO) thin films were grown on Pt(111)/SiO2/Si substrates by r.f. magnetron sputtering at substrate temperature ranging from 220°C to 320°C, and the preferred orientation of LNO was dominated by the substrate temperature. The oriented LaNiO3 served as a template for the subsequent (100)-oriented growth of deposited Ba0.5Sr0.5TiO3 (BST) thin film. Also, the tunability of BST thin film has been greatly improved with the insertion of (100)-textured LNO buffer layer. [Copyright &y& Elsevier]

Abstract: Oriented growth of polycrystalline rubrene thin film on oriented pentacene buffer layer was investigated. The oriented pentacene buffer layer was created by thermal evaporation of pentacene on a rubbed polyvinylalcohol (PVA) surface. The pentacene layer in turn induced the oriented growth of rubrene crystals upon thermal deposition. The structures of successive layers were characterized by using grazing incidence X-ray diffraction (GIXD) and atomic force microscopy. Highly oriented rubrene crystallites with the a-axis aligning along the surface normal and the (002) plane preferentially oriented 45° away from the rubbing direction were found. In contrast, the rubrene thin film deposited on PVA or rubbed-PVA substrate without a pentacene buffer layer only gave amorphous phases. With the aligned pentacene/rubrene film as the active layer of organic field-effect transistor, anisotropic mobilities were observed. The highest field-effect mobility (0.105cm2/Vs) was observed along the direction 45° away from the rubbing direction and is ∼4 times higher than that for similar device prepared on unrubbed PVA. The direction was consistent with the GIXD observation that a large number of rubrene crystallites are having their [002] direction aligning in this direction. A favourable C–H⋯π interaction between an oriented pentacene layer and the rubrene layer on the control of molecular orientation in the conduction channel of the OFET is suggested. [Copyright &y& Elsevier]

Abstract: The thickness dependence of microstructures of La0.9Sr0.1MnO3 (LSMO) thin films grown on exact-cut and miscut SrTiO3 (STO) substrates, respectively, was investigated by high-angle X-ray diffraction (HXRD), X-ray small-angle reflection (XSAR), X-ray reciprocal space mapping and atomic force microscopy (AFM). Results show that the LSMO films are in pseudocubic structure and are highly epitaxial [001]-oriented growth on the (001) STO substrates. The crystalline quality of the LSMO film is improved with thickness. The epitaxial relationship between the LSMO films and the STO substrates is [001]LSMO∥[001]EXACT-STO, and the LSMO films have a slight mosaic structure along the qx direction for the samples grown on the exact-cut STO substrates. However, an oriented angle of about 0.24° exists between [001]LSMO and [001]MISCUT-STO, and the LSMO films have a mosaic structure along the qz direction for that grown on the miscut STO substrates. The mosaic structure of both groups of the samples tends to reduce with thickness. The diffraction intensity of the (004) peaks increases with thickness of the LSMO film. The XSAR and AFM observations show that for both groups, the interface is sharp and the surface is rather smooth. The mechanism was discussed briefly. [Copyright &y& Elsevier]

Abstract: (100)- and (101)-oriented PbTiO3 (PT) thin films on conductive LaNiO3 (LNO)-coated Si(111) substrates were prepared by a metal-organic decomposition method. It is found that the crystallization states of LNO thin films used as buffer layers have significantly effects on preferential orientation of PT thin films. PT thin films with (100) orientation could be obtained not only on the crystalline LNO (100) film, but also on the amorphous LNO thin film. The highly (100)-oriented PT films show high dielectric constant of 189.4 on LNO (100) films and 183.1 on amorphous LNO films. The PT capacitors fabricated on the LNO buffer layers display good P–E hysteresis loops. The remnant polarization (P r) and coercive field (E c) of PT films on amorphous, (100)- and (110)-oriented LNO films are 9.35μC/cm2 and 162.8kV/cm, 10.03μC/cm2 and 163.3kV/cm, 11.23μC/cm2 and 166.2kV/cm, respectively. [Copyright &y& Elsevier]