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[Display omitted] • Diaminoguanidine hydrochloride was used as monomer for interfacial polymerization. • An aqueous-phase polymerization mechanism was proposed. • A TFC membrane with a positively charged interfacial layer was prepared. • The TFC membrane achieved a MgCl 2 rejection of 95.05% at 7 bar. • The TFC membrane achieved a separation factor of 23.32 at Mg2+/Li+ mass ratio of 10. This study aims to prepare and investigate thin film composite (TFC) membranes with a highly positively charged rejection layer for effective separation of Mg2+/Li+. The aqueous phase monomer employed in fabricating the TFC membranes was a highly ionic and hydrophilic guanidinium, namely 1,3-diaminoguanidine hydrochloride (DAGH), using an interfacial polymerization method. Two methods were used to prepare the TFC membranes: conventional interfacial polymerization and support-free interfacial polymerization. The surface properties and morphologies of the TFC membranes were characterized by FESEM, AFM, surface zeta-potential, and water contact angle. The XPS was used to analyze the crosslinking structure of the interfacial layer. The study results revealed that the SF-TFC membrane had a higher crosslinking density and zeta-potential compared to the C-TFC membrane. Notably, SF-TFC exhibited a MgCl 2 rejection of 95.09% at 7 bar, and for Mg2+/Li+ separation, the SF-TFC membrane had a Li+/Mg2+ separation factor of 23.32 at the Mg2+/Li+ mass ratio of 10. Additionally, the strong ionic and hydrophilic properties of DAGH led to the proposal of an aqueous-phase polymerization mechanism, substantiated by AFM and ESI-MS analysis. [ABSTRACT FROM AUTHOR]

The Cadmium telluride (CdTe) thin film has been prepared by physical vapor deposition (PVD), the Ar + O 2 pressure is about 0.9 kPa. This method is a newer technique to deposit CdTe thin film in large area, and the size of the film is 30 × 40 cm 2 . This method is much different from the close-spaced sublimation (CSS), as the relevance between the source temperature and the substrate temperature is weak, and the gas phase of CdTe is transferred to the substrate by Ar + O 2 flow. Through this method, the compact and uniform CdTe film (30 × 40 cm 2 ) has been achieved, and the performances of the CdTe thin film have been determined by transmission spectrum, SEM and XRD. The film is observed to be compact with a good crystallinity, the CdTe is polycrystalline with a cubic structure and a strongly preferred (1 1 1) orientation. Using the CdTe thin film (3 × 5 cm 2 ) which is taken from the deposited large-area film, the 14.6% efficiency CdS/CdTe thin film solar cell has been prepared successfully. The structure of the cell is glass/FTO/CdS/CdTe/graphite slurry/Au, short circuit current density ( J sc ) of the cell is 26.9 mA/cm 2 , open circuit voltage ( V oc ) is 823 mV, and filling factor (FF) is 66.05%. This technique can be a quite promising method to apply in the industrial production, as it has great prospects in the fabricating of large-area CdTe film. [ABSTRACT FROM AUTHOR]

The effects of atmospheric CO 2 on surface segregation and phase formation in La 0.6 Sr 0.4 Co 0.2 Fe 0.8 O 3− δ (LSCF-6428) were investigated. (0 0 1)-oriented LSCF-6428 thin films were deposited on lattice matched (1 1 0)-oriented NdGaO 3 (NGO) substrates by pulsed laser deposition (PLD). Using the synchrotron technique of total reflection X-ray fluorescence (TXRF), it was found that the kinetics of Sr surface segregation was enhanced when annealing at 800 °C in a high-CO 2 partial pressure, as compared to a similar anneal in a CO 2 -free atmosphere, with the oxygen partial pressure being constant in both cases. Hard X-ray photoelectron spectroscopy (HAXPES) measurements showed that the contribution of the surface carbonate to surface oxide phases increased significantly for the sample annealed in the high-CO 2 atmosphere. Atomic force microscopy (AFM) studies showed enhanced surface phase formation during the high-CO 2 partial pressure anneal. Density functional theory (DFT) calculations provide a thermodynamic basis for the enhanced kinetics of surface segregation in the presence of atmospheric CO 2 . [ABSTRACT FROM AUTHOR]

CeO 2 thin films were deposited on Si (1 1 1) substrates by laser molecular-beam epitaxy (LMBE). The thermal stability and surface behaviors of CeO 2 /Si samples were investigated by X-ray photoelectron spectroscopy during in-situ vacuum annealing. Temperature dependency of surface compositions was identified. At the temperature from 700 K to 1000 K, CeO 2 was reduced gradually, but incomplete transformation of CeO 2 to Ce 2 O 3 was found even when the sample was annealed at 1000 K for an hour. When the sample was exposed to oxygen ambience, the enhanced thermal stability of the partially reduced surface was revealed by the slight variation of Ce3d and Ce4d spectra. Si2p peak at 102.7 eV was detected on the top surface after the whole heating treatments, while not for the sub-surface during sputtering till to the interface. The Si signal at the outmost surface is induced by surface segregation due to the decreasing solid solubility of Si atoms in CeO 2 matrix with the decreasing temperature. At the interface, Si2p peaks at 99.9 eV with the presence of Ce4d peaks at 122.2 eV and 125.6 eV are attributed to the formation of cerium silicates with Ce–Si–O matrix during annealing due to interfacial reactions, which are supposed to stabilize the partially reduced ceria system. [ABSTRACT FROM AUTHOR]

A quaternary ammonium salt with bulk size and contorted configuration was effectively anchored to surfaces of polyethylenimine thin-film composite membranes, leading to 3 times higher water peremability coupled with good Magnesium/Lithium selectivity. [Display omitted] • Thin-film composite membranes were surface modified with a quaternary ammonium salt. • The membrane shows highly improved water permeability and good Mg2+/Li+ selectivity. • The membrane exhibits stable performance in separating Mg2+/Li+ mixture at 6 bar pressure. Nanofiltration plays emerging roles in lithium extraction from salt-lake brines with high magnesium-to-lithium (Mg2+/Li+) ratio, yet current lithium extraction nanofiltration membranes show relatively low water permeability. A new monomer (1-(2-hydroxyethyl)-1,3,5,7-tetraazaadamantane-1-ium bromide, HMTAB) was designed to improve membrane separation performances by means of surface modification. Infrared characterizations show that the HMTAB monomer was anchored the pristine polyethylenimine (PEI) thin film composite membrane through esterification condensation. Average roughness of the HMTAB membrane is relatively small (5.7 nm), while the thickness of the top-layer was increased by ∼ 20%, i.e., from 90 to 110 nm. Water flux of the HMTAB membrane in filtrating Mg2+/Li+ mixture (2000 ppm, Mg2+/Li+: 100) at 6 bar pressure is 97.9 L m-2h−1, which is 3.6 times as high as the pristine PEI membrane. Meanwhile, the Mg2+/Li+ ion selectivity of the HMTAB membrane is maintained, and the membrane reduced the high Mg2+/Li+ ratio (50) in the feed to a relatively low value (4.9) in the permeate. Last, the modified membrane exhibits stable performance in 40 h' continuous nanofiltration. [ABSTRACT FROM AUTHOR]

Highlights: [•] The transition temperature of the island growing from fractal to compact is demonstrated to increase with deposition rate. [•] The transition temperature of island evolution is deduced by the average island density distributions and demonstrated by the island morphology evolution. [•] As the interaction energy between adatom and defect point increases, the island shapes become small and irregular. [•] The island shapes cannot resemble the surface crystal structure even at high temperature. [ABSTRACT FROM AUTHOR]

[Display omitted] • Effective tuning of film nanostructures by varying CH 4 content in the gas mixture. • A dual nanostructure consists of large and small grains ranging of 5–10 and ∼ 200 nm. • Maintaining lubricant properties in a quasi-saturation state with 2.0 dpa damage. • Structural designing of NCD films for solid lubrication in irradiation environments. By varying the CH 4 content of the mixed gas precursor of hot-filament chemical vapor deposition, a group of nanocrystalline diamond (NCD) films was fabricated in a dual nanostructure with well-controlled growth of small and large grains with sizes of 5–10 and ∼ 200 nm, respectively. The irradiation resistance and tribological properties of the NCD films were studied before and after irradiation (by 3.25-MeV Xe15+ ions), and various characterization techniques were adopted to investigate the evolution of the bonding structures and tribological properties of the studied films. All the radiated films exhibited the same amorphous structure in the depth of the projected range and showed comparable lubricant properties and wear rates (1.2 × 10-7–1.9 × 10-7 mm3/N‧m), regardless of how the grain sizes changed in the range of 5–200 nm. Moreover, the friction coefficients of the radiated films were relatively lower and more stable than those of the pristine films, because of the radiation-induced reduction in the surface roughness and the formation of tribofilms with a graphite-like structure. The excellent maintenance of lubrication properties after heavy-ion irradiation provides a feasible route for the development of anti-irradiation films for use as a solid lubrication material in nuclear irradiation environments. [ABSTRACT FROM AUTHOR]

Abstract: Lead-free piezoelectric BaZr0.2Ti0.8O3–Ba0.7Ca0.3TiO3 (BCZT) thin films were grown on La0.7Sr0.3MnO3-buffered Si (001) by off-axis RF magnetron sputtering at temperatures ranging from 550 to 810°C. In this article, we present the detailed investigation on structure, leakage current behaviors and electromechanical properties of BCZT thin films. The crystallographic texture and grain size of the as-grown thin films are strongly dependent on the growth temperature, which consequently affects the leakage behaviors and local electromechanical properties. The crystallographic orientation becomes better and the grain size increases when increased the substrate temperature. The dominant leakage mechanism is found to be space-charge-limited conduction at low electric field, while a Fowler-Nordheim tunneling is confirmed in high electric field region for the films deposited at 710°C and 810°C. The increasing growth temperature also leads to remarkable improvement in the local electromechanical properties of the films. The BCZT film deposited at an optimal temperature of 810°C exhibits a considerably high effective piezoelectric coefficient d 33,f of 94±4pm/V, which is comparable to that of a typical lead zirconate titanate thin film. [Copyright &y& Elsevier]

Abstract: Among the titanium alloys employed as implant materials, the Ti6Al4V alloy is still widely used. Micro-arc oxidation (MAO) was used to prepare ceramic oxide layer containing calcium and phosphor on surface of Ti6Al4V alloy and then the specimens were hydrothermal synthesis (HS) treated, and then a thin hydroxyapatite ((Ca10(PO4)6(OH)2, HA) film was deposited on the surface. The biocompatibility of Ti6Al4V alloy, MAO alloy and sample treated by hydrothermal synthesis were evaluated. The biocompatibility of three specimens was tested using anti-hematolysis tests, anti-coagulation tests, anti-platelet adhesion and cytotoxicity tests. Specimens coated with HA film exhibited significant improved anti-hemolytic reaction, and the hematolysis ratio was 0.994% (less than 5%), which indicated that this type of samples could not induce acute hematolysis. And coagulation did not occur within 50min on the HA layer. There was almost no platelet adhered on the surface. The toxicity was ranked as 0 grades which indicated that it could not induce the cytotoxic effect. This demonstrates that the HA film can significantly improve the biocompatibility properties. [Copyright &y& Elsevier]

Abstract: The electrochemical measures in deformed AISI 304 stainless steels ranged from 0% to 24% were investigated. With the increasing of the strain α′-martensite was gradually increasing. Moreover, the morphologies and densities of dislocations changed with increasing strain. The Mott–Schottky plots showed that the maximum total of donor and acceptor densities in passive film occurred in borate buffer solution when ɛ-martensite was most, while in borate buffer solution with 5000ppm Cl− the maximum total of donor and acceptor densities occurred when the content of α-martensite was most. These results were proven by further impedance spectroscopy experiments. [Copyright &y& Elsevier]

Abstract: The ferroelectric domain structure and polarization switching of the BiFeO3 thin film deposited on Pt/Ti/SiO2/Si(111) substrate using rf magnetron sputtering technique were studied by piezoelectric force microscopy. The initial domains were dominanted by the upward polarization state in our sample. The positive and negative dc biases switched the ferroelectric domains downward and upward, respectively; and the upward switching was more difficult than the downward one, demonstrating an unsymmetric ferroelectric hysteresis loop in our sample. The electric field dependent experiments were carried out to understand the evolution of the domain switching, and the obvious change in phase image was obtained only when poling at +10V, which implied the poling was performed close to the coercive field. The uncomplete domain switching was attributed to the unsufficient bisas, the impurity defect and the strain conditions as the result of ferroelastic domain displacement/creation. [Copyright &y& Elsevier]

Abstract: The electrochemical behaviour of passive film formed on 2205 duplex stainless steel in 0.1M Na2S2O3 solutions was investigated using potentiodynamic polarization, EIS, Mott–Schottky analysis and the compositions of oxide film in different passive regions were carried out by XPS. The results indicated that the impedance is dependent on the applied potential indicating the occurrence of a charge transfer reaction in a porous film. The doping densities evaluated from Mott–Schottky plots demonstrated that there existence of two donor levels in the space charge layer of the passive films. The donor density (N D1 and N D2) values are in the range of 1020–1021 cm3, and decreases exponentially with increasing film formation potential, which is in good agreement with the theoretical consequences of the PDM. The polarization curve and XPS results shows that in the passive regions the 2205 duplex stainless steel exhibits different electrochemical and semiconductor properties. [Copyright &y& Elsevier]

Abstract: The objective of the present study is to preliminarily explore the effect of surface chemistry modification of Ti6Al4V with a fluorine-contained copolymer thin film on the cellular behavior of osteoblasts. A fluorine-contained random copolymer thin film was fabricated on Ti6Al4V substrate, and then characterized by X-ray photoelectron spectroscopy (XPS), contact angle meter and surface profiler. The results showed that the surface modification of Ti6Al4V alloy could simultaneously transform the surface chemical constitution and reduce the surface energy evidently. However, the surface morphology and roughness of the Ti6Al4V substrate were hardly changed after the modification. By immersion process with simulated body fluid (SBF) and then by in vitro cytotoxicity test with MC3T3-E1 osteoblasts, the fluorine-contained copolymer thin film exhibited desirable stability and admirable cytocompatibility. In conclusion, the fluorine-contained copolymer thin film could be easily applied in modifying various solid surfaces, and the as-fabricated film also has potential applications in biomedical field. [Copyright &y& Elsevier]

Abstract: A novel fluorine-contained random copolymer (2,3,4,5,6-pentafluorostyrene)-r-poly(4-vinyl benzocyclobutene) (P(PFSt-r-4-VBCB)) was synthesized, and then spin-coated onto Si substrates followed by thermal cross-linking to produce the copolymer ultra-thin films. Although the surface modification with the P(PFSt-r-4-VBCB) film was simple and did not rely on special surface chemical reactions, the film could decrease the surface energy significantly, more importantly; the film demonstrated excellent stability and corrosion resistance. This random copolymer film could find broad applications in modifying various solid surfaces to enhance the properties such as corrosion resistance and solvent resistance. [Copyright &y& Elsevier]

Abstract: Hydrogenated nanocrystalline silicon (nc-Si:H) grown by hot-wire chemical vapor deposition (HWCVD) has recently drawn significant attention in the area of thin-film large area optoelectronics due to possibility of high deposition rate. We report on the effects of diborane (B2H6) doping ratio on the microstructural and optoelectrical properties of the p-type nc-Si:H thin films grown by HWCVD at low substrate temperature of 200°C and with high hydrogen dilution ratio of 98.8%. An attempt has been made to elucidate the boron doping mechanism of the p-type nc-Si:H thin films deposited by HWCVD and the correlation between the B2H6 doping ratio, crystalline volume fraction, optical band gap and dark conductivity. [Copyright &y& Elsevier]

Abstract: Effect of surface physicochemical properties on the water film confined within a nanogap was investigated. The film thickness and friction force were measured by the Relative Optical Interference Intensity (ROII) method and a UMT-2MT tribotester. It was found that the confined water film formed the thicker lubricate film than the prediction of elastic–isoviscous lubrication theory. Experimental results indicate that the higher the solid/water interfacial energy is, the thicker lubricate film the highly viscous “interphase” water layer forms and the lower the friction force is. [Copyright &y& Elsevier]

Abstract: Plasma polymerization gains increasing interest for the deposition of films with functional properties suitable for a wide range of modern applications on account of its advantageous features. In this study, carbon dioxide (CO2) was chosen as carrier gas at flow rates of 30 and 60sccm, respectively and styrene vapor was used as the monomer to prepare polystyrene films on glass substrates. The structure and composition of the plasma polymerized films were characterized by X-ray photoelectron spectroscopy (XPS), Fourier transform infrared spectroscopy (FT-IR) and compared with the film prepared by conventional thermal polymerization. The morphology information of the films was provided by optical microscopy. XPS and FT-IR results reveal that chemical composition of the plasma polymerized films is different from that of the thermal polymerized film and that oxygen content in the plasma polymerized films increases with the flow rate of CO2. Furthermore, the presence of oxygen-containing groups on the surface of plasma polymerized polystyrene films is confirmed. It is also found that the composition and morphology of the plasma polymerized films are controlled by the flow rate of CO2. [Copyright &y& Elsevier]

Abstract: Ti or Ni films have been deposited on the diamond particle surfaces by pulsed laser deposition. Compressive resistance of the uncoated and coated diamond particles was measured, respectively, in the experiments. The compressive resistance of the Ti-coated diamonds particles was found much higher than that of the uncoated ones. It increased by 39%. The surface morphology is observed by the metallography microscope. The surface of the uncoated diamonds particles had many hollows and flaws, while the surface of Ni-coated diamond particles was flat and smooth, and the surface of Ti-coated diamond particles had some metal masses that stood out of the surface of the Ti-coated film. The components of the metallic films of diamond particles were examined by X-ray diffractometry (XRD). TiC was found formed on the Ti-coated diamond surface, which resulted in increased surface bonding strength between the diamond particles and the Ti films. Meanwhile, TiC also favored improving the bonding strength between the coated diamond particles and the binding materials. Moreover, the bending resistance of the diamond saw blade made of Ti-coated diamond was drastically higher than that of other diamond saw blades, which also played an important role in improving the blade''s cutting ability and lifetime. Therefore, it was most appropriate that the diamond saw blade was made of Ti-coated diamond particles rather than other materials. [Copyright &y& Elsevier]

Uranium nitride UN 1.85 thin films were successfully fabricated by radio frequency magnetron deposition on Si substrate, and the in-situ oxidation of UN 1.85 was carried out for insights into the initial oxidation behavior of UN 1.85. A gradual oxidation of UN 1.85 is identified, where the N is displaced by O resulting in the formation of a series of uranium oxy-nitrides under various oxygen exposures. Three characteristic U4f 7/2 peaks are corresponding to different intermediate uranium oxy-nitrides, where the higher the U4f 7/2 peak, the higher O content in the intermediate uranium oxy-nitrides. The intermediate with U4f 7/2 peak at relative lower position is further oxidized to those at higher energy side. The coexistence of U 4 O 9 and other uranium oxides in higher states UO 2+x on UN 1.85 oxidized surface is further identified by Raman spectroscopy, where the former is characterized with vibration signals at ~460 cm-1 and ~630 cm-1. A three-layered model is applied for the description of the oxidized UN 1.85 surface, and an excellent resistance of UN 1.85 against ambient corrosion is proved. The diagram of the three-layered structure of the oxidized UN 1.85 surface. • A three-layered structure is revealed on the oxidized UN 1.85 surface due to a rapid oxidation process with contacting to oxygen. • The coexistence of U 4 O 9 and other uranium oxides in higher states is identified on the outmost surface. • Three typical U4f 7/2 peaks corresponding to different intermediate uranium oxy-nitrides are observed, which are further oxidized to the one locating at higher energy side in the progressive oxidation mechanism. High N-content uranium nitride of UN 1.85 thin films were successfully fabricated by radio frequency magnetron deposition on Si substrate, and the samples were characterized by Auger Electron Spectroscopy (AES) and X-ray Photoelectron Spectroscopy (XPS), respectively. Furthermore, the in-situ oxidation of UN 1.85 was carried out under UHV condition with controlled oxygen exposure, which yields insights into the initial oxidation behavior of UN 1.85. A gradual oxidation of UN 1.85 is identified, where the N is displaced by O resulting in the formation of a series of uranium oxy-nitrides under various oxygen exposures. Three characteristic U4f 7/2 peaks locating at 378.6 eV, 379.9 eV and 380.4 eV are corresponding to different intermediate uranium oxy-nitrides, where the higher the U4f 7/2 peak, the higher O content in the intermediate uranium oxy-nitrides. The intermediate uranium oxy-nitride with U4f 7/2 peak at relative lower position is further oxidized to higher energy side by the gradual displacement of N by O. The U4f 7/2 peaks at 380.4 eV could be originated from the overlap of uranium oxides and uranium oxy-nitrides with the least N content among the three intermediates mentioned above. The coexistence of U 4 O 9 and other uranium oxides in higher states UO 2+x on UN 1.85 oxidized surface is further identified by Raman spectroscopy, where the former is characterized with vibration signals at ~460 cm−1 and ~630 cm−1. A three-layered model is applied for the description of the oxidized UN 1.85 surface, and an excellent resistance of UN1.85 against ambient corrosion is proved, where the oxidized thickness on the UN 1.85 sample exposed under laboratory ambience for 18 months is similar with that oxidized with 2000 L O 2 exposure under UHV condition. [ABSTRACT FROM AUTHOR]

• Successful growth of Cu 3 BiS 3 thin films using thermal evaporation. • Growth temperature enhances the photoelectric properties of Cu 3 BiS 3 thin films. • Cu 3 BiS 3 solar cell absorber was successfully implemented in solar cell device. Ternary copper sulphides, especially copper-bismuth-sulphide (Cu-Bi-S), are alternative solar absorber materials due to their earth-abundant and non-toxic constituent elements, compared to the conventional copper indium gallium sulphide and cadmium telluride films. In this study, Cu-Bi-S thin films were deposited onto soda lime glass substrates using a one stage co-evaporation process from Cu 2 S and Bi 2 S 3 sources, with the deposition temperatures varied from room temperature to 400 °C. X-ray diffraction analysis confirmed that Cu 3 BiS 3 was the dominant phase in the Cu-rich films, and the crystalline quality of the films was significantly improved with increasing the deposition temperature. An optical bandgap of 1.4 eV was achieved for the film deposited at 400 °C, which demonstrated a Hall mobility of 3.95 cm2/V-s and a carrier concentration of 7.48 × 1016 cm−3. Cu 3 BiS 3 films deposited at 375 and 400 °C were implemented into superstrate solar cell structures (glass/ITO/n-CdS/p-Cu 3 BiS 3 /Al). [ABSTRACT FROM AUTHOR]

In this work, we report the growth process of pristine and cobalt (2%, 4%, 6% and 8%) doped TiO 2 thin films on LaAlO 3 (100) substrate by molecular beam epitaxy (MBE) technique. The microstructural, magnetic, optical, photoconductivity and photocatalytic activity of the films were explored. Reflection high-energy electron diffraction (RHEED) confirms successful growth of single phase anatase TiO 2 thin film and effects of cobalt (Co) doping on crystal phase depending on the growth conditions and correlating changes in their physical properties. X-ray diffraction and X-ray photoelectron spectroscopy (XPS) establish highly pure crystalline nature and oxidation state of the elements. Magnetic measurements show room temperature ferromagnetism in all the thin films and suggest that growth conditions, oxygen vacancies and bound magnetic polaron (BMP) model account for the magnetic properties. The optical properties exhibit a red shift response associated with narrowing bandgap that influence photocatalytic activity. The 8% cobalt doped TiO 2 film has shown 91% degradation with methylene blue and 88% degradation with Azo dye in 70 min under visible light irradiation exhibiting excellent photocatalytic performance. The photoconductivity measurements have confirmed photosensitive nature of TiO 2 and 8% Co doped TiO 2. Therefore, these opto-magnetic properties can be tuned for the applicability of future spintronic and optical devices. Unlabelled Image • Thin films of pristine and cobalt doped TiO 2 were grown on LaAlO 3 substrate by MBE. • Enhancement in room temperature ferromagnetism has been observed in doped samples. • Co doped films demonstrate excellent photocatalytic activity for MB/Azo dyes. • The photoconductivity measurement confirms photosensitive nature of the films. • Opto-magnetic properties can be tuned for future spintronic and optical devices. [ABSTRACT FROM AUTHOR]

Superhydrophobic TiO 2 films with micro-patterned surface structure was prepared through a facial approach combining photosensitive sol–gel method with following surface modification by 1H,1H,2H,2H-perfluorooctyltrichlorosilane (PFOTCS). The patterned surface possessed quasi micro-lens array structure resembling processus mastoideus of lotus, leading to excellent hydrophobicity. The relationship between hydrophobic performance and the period of the micro-patterned TiO 2 surface was investigated. The water contact angles (CAs) of micro-patterned TiO 2 surface increased with the decrease of the periods, and the patterned surface with the lowest period of 0.83 μm showed the highest CA of 163°. It suggests that this approach would offer an advantage to control the wettability properties of superhydrophobic surfaces by adjusting the fine pattern structure. Furthermore, the superhydrophobic state could be converted to the state of superhydrophilicity under ultraviolet (UV) illumination as a result of the photocatalytic decomposition of the PFOTCS monolayer on the micro-patterned TiO 2 Surface. [ABSTRACT FROM AUTHOR]

Catalyst films for methanol combustion, which could be used as micro heat source to provide energy for micro–nano-scale devices, were fabricated with an inkjet printing method. The inkjet printing was used to prepare catalyst films by optimizing inkjet-printed parameters (voltage: 65–70 V; pulse width: 20–30 μs; ink viscosity: near 1 mPa s) and depositing uniform morphologies (substrate temperature: 80 °C; water/ethylene glycol (W/EG): 95:5, v/v). The performances of micro catalytic heat source were evaluated by an infrared thermography (IR) camera. The temperature response reached 95% of the steady state temperature in about 150 s, the temperature difference reached 100 °C on the catalyst surface, and the temperature of catalytic combustion was controlled by adjusting the methanol/air (10% v/v) flow rate. [ABSTRACT FROM AUTHOR]

Highlights: [•] The multiferroic properties of BiFeO3 thin films are highly enhanced by (Tb, Mn) co-doping. [•] With the co-doping, the structural transformation from rhombohedral R3c to triclinic P1 is confirmed through structural characterization. [•] A giant remanent polarization of 2P r =180.3–142.2μC/cm2 is obtained by the co-doping. [ABSTRACT FROM AUTHOR]

Highlights: [•] Effects of deposition parameters on the properties of Bi2Se3 films were investigated. [•] Mechanism of grown different morphologies of the Bi2Se3 films was described. [•] Carrier concentration tends to decrease with increasing ambient pressure. [•] A phase diagram of power factor as a function of deposition parameters is obtained. [•] The best power factor achieved 5.54μWcm−1 K−2 for the film grown at 300°C and 40Pa. [ABSTRACT FROM AUTHOR]

Abstract: Ag/PMMA nanocomposites have attracted much attention due to its superior mechanical, optical and electrical properties. In this article, Ag/PMMA nanocomposite films with high silver content (20wt%) have been successfully in situ synthesized. UV–vis analysis, transmission electron microscopy (TEM), current–voltage (I–V) analysis, hall effect measurement system and electrochemical workstation are used to characterize the nanocomposite films. The results reveal that silver nanoparticles (NPs) homogeneously distribute in PMMA films and the particles size of silver NPs which has been controlled from 1.68 to 6.98nm. Ag/PMMA nanocomposite films show electrical properties due to the conduction paths created by Ag nanoparticles. With the increasing diameter of silver NPs, the current density decreases and resistivity increases, respectively. Photo-responsive properties of Ag/PMMA nanocomposite films indicate that conduction paths could be destroyed by illumination and rebuilt in dark condition. [Copyright &y& Elsevier]

Abstract: A confocal Raman investigation of Pb1− x La x Ti1− x/4O3 (PLT) thin films grown by RF magnetron sputtering on PbO x /Pt/Ti/SiO2/Si substrates with an intermediate LaSrCoO3 (LSCO) layer was performed. The influence of the LaSrCoO3 buffer layer was analyzed taking advantage of the observed Raman spectral band variation, which varied according to different manufacturing procedures. In the presence of a LSCO layer, the A1(1TO) Raman mode, which was indicative of tetragonal distortion, was pronouncedly enhanced, and a slight deviation from the (001) plane of the film was observed from the angular dependence of the polarized Raman spectral intensity. Furthermore, the spectral band variation as well as the residual stress along the in-depth direction was measured in the film from cross-sectional spectral line scans. This latter measurement showed a relaxation of the lattice mismatch in the presence of LSCO and PbO layers. [Copyright &y& Elsevier]

Abstract: With the increase of magnetic storage density, the thickness of the protective diamond like carbon (DLC) film on the surfaces of head and disk is required as thin as possible. In this paper, the structure, mechanical properties and corrosion and oxidation resistance of ultra-thin DLC films are investigated. The ultra-thin DLC films were deposited by using filtered cathodic vacuum arc (FCVA) technique. The exact thickness of the ultra-thin DLC film was determined by high resolution transmission electron microscope (HRTEM). Raman analysis indicates that the ultra-thin DLC film presents ta-C structure with high sp3 fraction. In the wear test, a diamond tip was used to simulate a single-asperity contact with the film surface and the wear marks were produced on the film surface. The wear depths decrease with film thickness increasing. If the film thickness was 1.4nm or above, the wear depth was much lower than that of Si substrate. This indicates that the ultra-thin DLC film with thickness of 1.4nm shows excellent wear resistance. Corrosion tests in water and oxidation tests in air were carried out to investigate the diffusion barrier effect of the ultra-thin DLC films. The results show that the DLC film with thickness of 1.4nm provides adequate coverage on the substrate and has good corrosion and oxidation resistance. [Copyright &y& Elsevier]

Abstract: The effect of substrate roughness on growth of ultra thin diamond-like carbon (DLC) films has been studied. The ultra thin DLC films have been deposited on silicon substrates with initial surface roughness of 0.15, 0.46 and 1.08nm using a filted cathodic vacuum arc (FCVA) system. The films were characterized by Raman spectroscope, transmission electron microscope (TEM) and atomic force microscopy (AFM) to investigate the evolution of the surface roughness as a function of the film thickness. The experimental results show that the evolution of the surface morphology in an atomic scale depends on the initial surface morphology of the silicon substrate. For smooth silicon substrate (initial surface roughness of 0.15nm), the surface roughness decreased with DLC thickness. However, for silicon substrate with initial surface roughness of 0.46 and 1.08nm, the film surface roughness decreased first and then increased to a maximum and subsequently decreased again. The preferred growth of the valley and the island growth of DLC were employed to interpret the influence of substrate morphology on the evolution of DLC film roughness. [Copyright &y& Elsevier]

Recently, memristors have attracted considerable attention because of their potential applications in artificial neural networks which will promote the future development of artificial intelligence. In this work, the analogue memristive and related synaptic behavior of memristors based on single crystalline LiNbO 3 thin films have been studied. Low energy Ar+ ions irradiation was applied to locally dope the LiNbO 3 thin films by controllably introducing oxygen vacancies acting as donors. The resistive switching performance and synaptic plasticity can be tuned by changing the size or the number of the irradiated regions below the top electrode. Linear regression, an important fundamental function belonging to the machine learning in artificial intelligence, was emulated using memristors with different synaptic plasticity. It has been shown that the local doping method significantly influences the linear regression process. • Single crystalline LiNbO 3 thin films were used to exclude negative influence of co-existence of grains and grain boundaries • Resistive switching behaviors of Ar+-irradiated LiNbO 3 thin film were systematically studied and analyzed. • Properties of memristors for neuromorphic computing were tuned by changing the number of local Ar+-irradiated-zones • Performances of basic artificial neural networks realized by memristor with different properties were compared [ABSTRACT FROM AUTHOR]

This study compares the tribological performance of polytetrafluoroethylene (PTFE) thin film coating reinforced with black phosphorus (BP) or ball-milled graphite (BMG) nanoparticles, so as to elucidate their mechanism of action under reciprocating sliding test conditions. PTFE coatings with 0.5 wt.% BMG (BMG/PTFE) and 0.5 wt.% BP (BP/PTFE) were prepared on GCr15 bearing steel disk by using a spin coater. The friction and wear tests were carried out by using the ball-on-disk tribometer under a normal load of 1 N (contact pressure: 780 MPa), a frequency of 2 Hz, and 4.2 mm sliding displacement amplitude. The surface roughness, wear volume and surface morphology of the coatings were characterized by the three-dimensional white light, and Energy Dispersive X-ray Detector (EDX) analysis coupled with environmental scanning electron microscope (ESEM). It is found that BP/PTFE coating has better anti-wear and anti-friction performances than those of pure PTFE or BMG/PTFE coating. The coating with BP nanoparticles shows excellent tribological properties with the wear volume decreased from 3.52 × 10 6  μm 3 to 1.64 × 10 6  μm 3 and the coefficient of friction (COF) decreased from 0.117 to 0.046. More importantly, the BP layer probably expands and absorbs much energy due to its negative Poisson's ratio phenomenon under reciprocating sliding, and effectively reducing furrow and adhesive wear. [ABSTRACT FROM AUTHOR]

Core-shell structure PtO 2 @Pt nanodots have been self-assembly by vacuum sputtering and high temperature annealing. First, Pt thin films with a small amount of PtO 2 are grown on the sapphire substrates by vacuum sputtering. And then high temperature annealing on the thin films is carried out at 800 °C for 2 min to form Pt nanodots. During the cooling process, the atmosphere is deployed to supplant the nitrogen. Finally, even distributed core-shell structure PtO 2 @Pt nanodots with a diameter from 100 to 300 nm are achieved. Furthermore, the formation evolution of core-shell structure PtO 2 @Pt nanodots is also proposed. This work open up a new approach for fabricating core-shell structure nanodots. [ABSTRACT FROM AUTHOR]

[Display omitted] • The a-axis-oriented SnSe thin films prepared via atomic layer deposition. • The preparation of wafer-scale SnSe ambipolar thin film transistor arrays with copper-assisted exfoliation. • High mobilities of 41.29 and 34.99 cm2 V−1 s−1 for holes and electrons, respectively. SnSe is a layered metal chalcogenide with potential ambipolar applications. However, the scale of devices is subject to limitation of milli/centi-meter-sized two-dimensinal (2D) flakes. Here, we demonstrate the preparation of wafer-scale SnSe ambipolar thin film transistor (TFT) arrays. The a-axis-oriented SnSe thin films were prepared via atomic layer deposition. The processes of lithography and copper-assisted exfoliation help to peel off unnecessary films to form isolated SnSe flakes. After evaporating nickel as contact electrodes, TFT arrays were successfully fabricated. The on/off current ratios are upgraded from 103 to 104 through annealing at 500 °C to improve the crystalline quality of SnSe, and both hole and electron mobilities increase fivefold to 41.29 and 34.99 cm2 V−1 s−1, respectively. The devices exhibit from symmetric ambipolar to hole-dominated behaviors as SnSe channel thickness increases to 50 nm. The copper-assisted exfoliation method provides an etching technique to make patterned 2D devices. [ABSTRACT FROM AUTHOR]

A network structure of PANI / SnO 2 hybrid was synthesized by an in situ chemical oxidative polymerization using cheaper ZnO nanorods as sacrificial template and the hybrid was loaded on a flexible polyethylene terephthalate (PET) thin film to construct a flexible smart sensor. The sensor not only exhibits high sensitivity which is 20 times higher than that of pure PANI to 10 ppm triethylamine, good selectivity and linear response at room temperature but also has flexible, structure simple, economical and portable characters compared with recently existing sensors. Room temperature operating of the sensor is also particularly interesting, which leads to low power consumption, environmental safety and long life times. The improvement of sensing properties is attributed to the network structure of hybrid and formation of p - n heterojunction at the interface between the PANI and SnO 2 . The research is expected to open a new window for development of a kind of wearable electronic devices based on the hybrid of conducting polymer and metal oxides. [ABSTRACT FROM AUTHOR]

[Display omitted] • A V o reservoir is introduced on single-crystalline LiNbO 3 film by Ar+ irradiation. • Reliable resistive switching with low temporal and spatial variations is realized. • Abundant synaptic functions included short- and long-term plasticity are emulated. • Residual-channel-guided channel reconstruction enhances the switching uniformity. Typical filament-type memristors suffer from temporal and spatial variations in the resistive switching due to stochastic filament formation, which hinders the implementation of memristive synapses in neuromorphic computing. In this work, the memristor based on Ar+-irradiated single-crystalline LiNbO 3 (SC-LNO) thin film is reported. The high-quality SC-LNO thin films contribute to the formation of more concentrated and robust oxygen vacancy channels (OVCs) and lead to reliable self-rectifying resistive switching behaviors with an ultra-low device-to-device variability of ∼2.80% and cycle-to-cycle variability of ∼2.25%, as well as long retention time at multilevel resistance states (>3 × 104 s), stable endurance performance (>105 cycles), excellent environmental stability (>6 months), and good analog switching linearity. Furthermore, abundant synaptic plasticity characteristics including paired-pulse facilitation (PPF), post-tetanic potentiation (PTP), long-term potentiation (LTP), long-term depression (LTD), spike-timing-dependent plasticity (STDP), and associative learning, are also successfully emulated using this device as an electronic synapse. The spontaneous decay process right after applied voltage pulses and the long-term nonvolatility characteristics in Ar+-irradiated SC-LNO memristor indicate the existence of residual OVCs, which serves to guide the reconstruction of OVCs during repeated switching and to further enhances the uniformity of device switching characteristics. [ABSTRACT FROM AUTHOR]

The SnO 2 :Sb thin films (ATO) were deposited on quartz glass by magnetron sputtering. The effects of post-growth annealing on preferential orientation, microstructure and functional properties of thin films have been investigated. It was found that the thin films were polycrystalline with the cassiterite tetragonal (rutile type) structure. As the annealing temperature increased from 200 °C to 600 °C, the crystalline quality of the thin films improved. The texture transition from (2 0 0) to (2 1 1) crystallographic orientations was found as annealing temperature increased to 600 °C. This result revealed that the process of abnormal grain growth occurred. However, the crystalline quality was subsequently deteriorated with further increase of the annealing temperature. The obtained ATO thin film annealed at 600 °C showed the lowest resistivity of 1.5 × 10 −3 Ω cm with the carrier concentration of 2.11 × 10 20 cm −3 and hall mobility of 21.37 cm 2 V −1 s −1 . The average optical transmittance was 84.9% in the visible wavelength range from 380 to 780 nm. In addition, the mechanism of the changes of electrical and optical properties at different annealing temperature was proposed. [ABSTRACT FROM AUTHOR]

Highlights: [•] The obstructive effect of CO on methanol decomposition on Pt nanoclusters on the Al2O3/NiAl(100) was studied. [•] The probability of dehydrogenation of methanol was decreased by pre-adsorbed CO to half. [•] The pre-adsorbed CO obstructed less effectively the C O bond scission of methanol. [•] The produced CO with atomic hydrogen from dehydrogenated methanol exhibited a comparable effect. [ABSTRACT FROM AUTHOR]

Highlights: [•] Zn-Sb thin film thermoelectric property enhanced via phase optimization. [•] The carrier concentration is suitable for obtaining high-quality sample. [•] Zn-Sb thin film with mixed ZnSb and Zn4Sb3 phase has highest power factor. [ABSTRACT FROM AUTHOR]

Highlights: [•] Trilon® P is used as a critical additive in copper slurries to improve the copper CMP performance, especially in the aspects of realizing low SER, low dishing and low dielectric erosion. [•] The chelating reactions between Trilon® P and cupric ions are revealed. [•] The reaction product Cu–Trilon® P complex has dual functions for copper CMP: passivation and lubrication vs. complexation and facilitation of (*OH) formation. [•] The adsorption of Trilon® P on the PETEOS surface can help form a lubricating thin film, and thus can result in low dielectric erosion. [ABSTRACT FROM AUTHOR]

Highlights: [•] ZnO films were grown by thermal and remote plasma-enhanced atomic layer deposition. [•] Structure, optical, electrical and resistive switching properties of ZnO thin films. [•] PEALD-ZnO devices show resistive switching properties, while Thermal ALD devices not. [•] The thickness of ZnO layer has a strong effect on the resistive switching properties. [ABSTRACT FROM AUTHOR]

[Display omitted] • High purity Sb films were prepared via a simple vapor deposition method. • Two kinds of photodetector were fabricated by using the Sb films. • The Sb photodetectors exhibit self-powered, broad band photodetection and flexibility. Antimony (Sb) thin film has drawn substantial attention in recent years due to its high carrier mobility, tunable bandgap, superior thermal conductivity, and high stability. Here, two kinds of Sb photodetector are presented. The Sb photodetector based on SiO 2 /Si exhibits fast photoresponse from ultraviolet (UV) to near infrared (NIR) wavelengths and a self-powered behavior without bias voltage. The Sb photodetector based on flexible polyimide (PI) substrate also exhibits self-powered and fast photoresponse features similar to the rigid Sb/SiO 2 photodetector, furthermore the flexible photodetector exhibits excellent mechanical flexibility and stable photoresponse under a wide bending range of curvatures and a large number of bending cycles. The results of this work indicate that Sb thin film has a great potential in the development of self-powered, flexible, and broadband photodetector in the future. [ABSTRACT FROM AUTHOR]

[Display omitted] • Mn doping into the NBT-SBT thin films can improve the insulation performance and advance the ferroelectric properties. • The ordered cation displacement can only be maintained in a single nano-sized crystal grain, and its order scale is limited by the grain size. The nanoscale grain size is responsible for the obtained slim P - E hysteresis loops. • The 0.55NBT-0.45SBT-0.01Mn film exhibited relatively high recoverable energy storage density (∼30.5 J/cm2) and efficiency (∼65%) with reliable frequency and antifatigue stability. The 0.55Na 0.5 Bi 0.5 TiO 3 -0.45Sr 0.7 Bi 0.2 TiO 3 (0.55NBT-0.45SBT) thin films with Mn doping were fabricated on the platinum-buffered Si substrates using the sol–gel technique. The impacts of Mn doping on the structure and properties of the thin films were systematically studied. Mn doping into the thin films can limit the valence transition of Ti cations to improve the insulation performance, and advance the ferroelectric properties. Ordered B-site cation displacement can be observed from the HADDF-STEM image, which can only be maintained in a single nano-sized crystal grain, and its order scale is limited by the grain size. The 0.55NBT-0.45SBT-0.01Mn film exhibited relatively high recoverable energy storage density (∼30.5 J/cm2) and efficiency (∼65%) at 2800 kV cm−1. Frequency stability in a wide range (0.5 ∼ 20 kHz) and long-term antifatigue stability (1 × 108 switching cycles) were also obtained, indicating their future applications in advanced dielectric capacitors for energy storage. [ABSTRACT FROM AUTHOR]

Abstract: Scandium films were deposited on molybdenum (Mo) substrates, at different substrate temperatures (100–650°C) by electron-beam evaporation. The oxidation behavior was investigated by X-ray photoelectron spectroscopy (XPS). Hardness and elastic modulus of Sc films were measured by the nano-indentation technique. XPS depth profile results demonstrate that Sc films deposited at lower substrate temperatures are oxidized easier than those at higher temperatures. Besides the effect of thermodynamics, the easier oxidation at lower temperatures may be attributed to the smaller grain size and lower diffusibility of oxygen in the inner film. Increasing substrate temperature first decreases the hardness and elastic modulus due to the increased grain size and decreased degree of oxidation. Then, when the temperature increases from 450°C to 550°C, the hardness and elastic modulus are improved owing to the higher texture coefficient and densification, as well as the abnormally decreased grain size. However, when the temperature further increases to 650°C, the hardness and elastic modulus decrease again. [Copyright &y& Elsevier]

Abstract: Electrodeposition was employed to fabricate magnetite (Fe3O4) coated carbon fibers (MCCFs). Temperature and fiber surface pretreatment had a significant influence on the composition and morphology of Fe3O4 films. Uniform and compact Fe3O4 films were fabricated at 75°C on both nitric acid treated and untreated carbon fibers, while the films prepared at 60°C were continuous and rough. Microwave measurements of MCCF/paraffin composites (50wt.% of MCCFs, pretreated carbon fibers as deposition substrates) were carried out in the 2–18GHz frequency range. MCCFs prepared at 60°C obtained a much higher loss factor than that prepared at 75°C. However, the calculation results of reflection loss were very abnormal that MCCFs prepared at 60°C almost had no absorption property. While MCCFs prepared at 75°C exhibited a good absorption property and obtained −10dB and −20dB refection loss in wide matching thickness ranges (1.0–6.0mm and 1.7–6.0mm range, respectively). A secondary attenuation peak could also be observed when the thickness of MCCF/paraffin composite exceeded 4.0mm. The minimum reflection loss was lower. [Copyright &y& Elsevier]

Abstract: ZnO:N thin films were deposited on sapphire substrate by metal organic chemical vapor deposition with NH3 as N-doping sources. The reproducible p-type ZnO:N film with hole concentration of ∼1017 cm−3 was successfully achieved by subsequent in situ thermal annealing in N2O plasma protective ambient, while only weak p-type ZnO:N film with remarkably lower hole concentration of ∼1015 cm−3 was obtained by annealing in O2 ambient. To understand the mechanism of the p-type doping behavior of ZnO:N film, X-ray photoelectron spectroscopy (XPS) and soft X-ray absorption near-edge spectroscopy (XANES) measurements have been applied to investigate the local electronic structure and chemical states of nitrogen atoms in ZnO:N films. [ABSTRACT FROM AUTHOR]

Abstract: A simple, inexpensive and environmental chemical treatment process, i.e., treating porous poly(tetrafluoroethylene) (PTFE) films by a mixture of potassium permanganate solution and nitric acid, was proposed to improve the hydrophilicity of PTFE. To evaluate the effectiveness of this strong oxidation treatment, contact angle measurement was performed. The effects of treatment time and temperature on the contact angle of PTFE were studied as well. The results showed that the chemical modification decreased contact angle of as-received PTFE film from 133±3° to 30±4° treated at 100°C for 3h, effectively converting the hydrophobic PTFE to a hydrophilic PTFE matrix. The changes in chemical structure, surface compositions and crystal structure of PTFE were examined by attenuated total reflection–Fourier transform infrared spectroscopy (ATR–FTIR), X-ray photoelectron spectroscopy (XPS), environmental scanning electron microscopy (ESEM), X-ray diffraction (XRD), respectively. It was found that the F/C atomic ratio decreased from untreated 1.65–0.10 treated by the mixture at 100°C for 3h. Hydrophilic groups such as carbonyl (Cdroxyl (introduced on the surface of PTFE after treatment. Furthermore, hydrophilic compounds K0.27MnO2·0.54H2O was absorbed on the surface of porous PTFE film. Both the introduction of hydrophilic groups and absorption of hydrophilic compounds contribute to the significantly decreased contact angle of PTFE. [Copyright &y& Elsevier]

Abstract: Based on the lotus effect principle, the superhydrophobic poly(vinylidene fluoride) (PVDF) film was successfully prepared by the method of alkali treatment enhancing chemical bath deposition. The surface of PVDF film prepared in this work was constructed by many smooth and regular microreliefs. Oxygen-containing functional groups were introduced in PVDF film by treatment with aqueous NaOH solution. The nano-scale peaks on the top of the microreliefs were implemented by the reaction between dimethyldichlorosilane/methyltrichlorosilane solution and the oxygen-containing functional groups of PVDF film. The micro- and nano-scale structures, similar to the lotus leaf, was clearly observed on PVDF film surface by scanning electronic microscopy (SEM) and atomic force microscope (AFM). The water contact angle and sliding angle on the fabricated lotus-leaf-like PVDF film surface were 157° and 1°, respectively, exhibiting superhydrophobic property and self-cleaning property. [Copyright &y& Elsevier]

Abstract: The tribological properties of three different films commonly used in microelectromechanical systems (MEMS) under the lubrication of ionic liquid (IL)/water mixtures with various concentrations in the running-in process have been investigated. Results show that coefficients of friction (COFs) and wear rates for low temperature silicon oxide (LTO)/Si3N4 vary in a similar way to the ones for poly-Si/Si3N4 under the lubrications of different IL/water mixtures. In contrast, the differences in COFs and wear rates are more significant in that the COFs and wear rates increase dramatically with the decrease in IL/water concentration in the case of self-mated Si3N4, while the differences in COFs and wear rates for the two other tribopairs are relatively small when the concentration is changed. The period of the running-in process reduces with the increase in IL/water concentration for all the tribopairs. Effective hydrodynamic lubrication can be found in the case of Si3N4/Si3N4 tribopair at higher IL/water concentrations without an evident running-in process, however, such a phenomenon cannot be observed for the other two tribopairs. Different wear mechanisms will also be analyzed in this paper. [Copyright &y& Elsevier]

Abstract: Al-doped zinc oxide (AZO)/Fe/AZO composite films were fabricated by a RF sputtering method. The effects of introducing of Fe layer into AZO film on the structural, optical, electrical and magnetic properties of the composite films were investigated. The results showed that these physical properties of the composite films depend strongly on the Fe layer thickness and heat-treatment temperature. The Hall coefficient is also closely dependent on the Fe layer thickness. With increasing the Fe layer thickness, carrier concentration increases while Hall mobility decreases. The results show that it is possible to produce a composite film material with high optical transmittance in the visible range, low resistivity and ferromagnetism at room temperature by introducing a magnetic metal thin layer into transparent and conductive films. The best electrical, optical and room-temperature ferromagnetic properties were achieved for the AZO/Fe/AZO composite films with a Fe layer thickness of 5nm annealed at 400°C for an hour. [Copyright &y& Elsevier]

Abstract: ZnO thin film was deposited on semi-insulating GaAs by metal organic chemical vapor deposition (MOCVD). In situ annealing treatments were carried out under different temperature. Hall and photoluminescence (PL) measurements showed that the electrical and optical properties of ZnO film were sensitively dependent on annealing temperature. The as-deposited ZnO film showed n-type conductivity and intense near band edge (NBE) emission combined with rather weak deep level (DL) emission. After annealing in the temperature of 520 and 560°C the films exhibit p-type conductivity, meanwhile secondary ion mass spectroscopy demonstrated arsenic ion was uniformly distributed in the ZnO films. Distinctly recombination of donor acceptor pair (DAP) was observed from the p-type ZnO film. The calculated arsenic related acceptor binding energy is nearly consistent with that of AsZn–2VZn acceptor complex. When the annealing temperature up to 640°C, Ga ion began to diffuse into ZnO film and the film returned to n-type as well as donor related emission reappeared in the spectrum. The influence of GaAs substrate on the electrical properties of ZnO films was also discussed. [Copyright &y& Elsevier]