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As a new type of reversible phase change material, vanadium dioxide (VO2) has shown great potential in development with the regulation of its phase change temperature (TMIT) and were extensively studied. The experiment in this study focuses on exploring the effect of germanium ions on TMIT of VO2 thin films and trying to explain the internal mechanism. A series of VO2 films containing different ratios of germanium ions were deposited on polished alumina sheets. The characterization results show that germanium ions contribute to increasing TMIT (maximum TMIT is 84. 7 ℃). The main reason for this increase is that germanium ion enhances the stability of monoclinic V-V dimer by increasing the stability of monoclinic V-V dimer, which makes the transition from low-temperature monoclinic state to tetragonal rutile state more difficult. [ABSTRACT FROM AUTHOR]

The substrate temperature of Ge2Sb2Te5 (GST) optoelectronic devices can influence various physical parameters, which could be helpful for tuning optoelectronic device structure and working performance as per desired use. Therefore, it is customary to demonstrate the GST/indium tin oxide (ITO)/substrate device structural, optical, and electrical properties with various substrate temperatures, such as room temperature, 150°C, and 200°C. It has been observed that a distinct phase formation in Ge2Sb2Te5 thin films occurs with increasing substrate temperature. An increase in the thickness of the thin films with increasing substrate temperature is verified by field emission scanning electron microscopy (FESEM) cross-sectional view, while the presence of the alloying elements and their particle distributions throughout the configuration are confirmed from energy-dispersive spectroscopy (EDS) and EDS mapping. The developed distinct morphological grains and corresponding roughness parameters of the thin film are interpreted with the help of atomic force microscopy (AFM) results. Moreover, the Raman spectroscopic broad peak of GeSbTe along with a distinguishable difference in GeTe phase peak height is also noticed. The correlation of Raman peak phase formation is described with the help of mapping analysis. Additionally, the Fourier transform infrared (FT-IR) (UV/visible range) transparency property and electrical parameters like I–V and R–V characteristics under the applied distinct voltages are also interpreted for these systems. [ABSTRACT FROM AUTHOR]

Herein, NiMn 2 O 4 (MNO) spinel oxide thermistor films were synthesized on a SiO 2 /Si substrate via annealing the electron beam evaporated Mn–Ni–Mn metal trilayers in air at different temperatures. The X-ray diffraction (XRD) results indicate that polycrystalline spinel-structured MNO thermistor films were formed. The surface particle size of the series MNO films quickly reduced from ~300 to ~120 nm with a temperature increase from 650 to 750 °C, and then, slowly reduced to 80 nm or even smaller with a temperature increase from 750 to 950 °C. Specifically, 750 °C anneal formed the spinel MNO film with largest B value of 5067 and Ea value of 0.4366. The proposed synthesis route for MNO spinel oxide film has been proven to be feasible. [ABSTRACT FROM AUTHOR]

Abstract Highly (l00)-oriented Ni-doped Na 0.5 Bi 0.5 TiO 3 (NBTNi) thin films with different A-site cation nonstoichiometry were deposited on the LaNiO 3 (100)/Si substrates. We find that low levels of Na/Bi nonstoichiometry in the original composition of NBTNi films have obvious influence on the crystal structure and ferro-/dielectric properties. Na deficiency or Bi excess can lower the leakage current compared to the stoichiometric sample due to the decreased oxide-site vacancies. However, the mechanisms for the two types of films are different. That is, the mobile oxygen vacancies are tied by the Na vacancies in Na deficiency film whereas the formation of oxygen vacancies is suppressed for Bi-rich film. A good combination of ferroelectric property (P r = 22.7 μC/cm2) and dielectric property (ε r = 360 and tan δ = 0.11) can be achieved in Bi-rich NBTNi (Na 0.5 Bi 0.54 TNi) film. Besides, the effect of voltage and frequency on the capacitance and dielectric tunability for the Na 0.5 Bi 0.54 TNi film is investigated solely. These results show that NBT-based thin film is quite flexible in A-site nonstoichiometry, which provides a broad space for performance improvement. [ABSTRACT FROM AUTHOR]

Abstract In the present study, the AgInSe 2 (AIS) thin films 500 nm in thickness were prepared by selenization of the Ag/In/Ag/In multilayer deposited by DC magnetron sputtering. The selenization was carried out at 250 °C and was followed by annealing at 450 °C, 475 °C and 500 °C. The selenized and annealed films were characterized by grazing incidence X-ray diffraction (GIXRD), UV-Visible-NIR spectroscopy, Field-Emission Scanning Electron Microscopy (FESEM) and Raman spectroscopy. The XRD analysis revealed the formation of the desired AgInSe 2 phase along with Ag 2 Se (AS) impurity phase. The impurity Ag 2 Se phase is being diminished at higher annealing temperature (500 °C) resulting the formation of AgInSe 2 phase. The super ionic nature of α-Ag 2 Se phase facilities the diffusion of Ag ion with its neighbouring tetrahedral sites. The low band gap Ag 2 Se impurity phase suppression by annealing at 500 °C lead to optical band gap increase. The Raman spectrum shows individual AgInSe 2 and Ag 2 Se peaks and also the overlapping of these two phases. The Ag 2 Se peaks are vanished after annealing. The EDXRF study revealed that the film is off-stoichiometric and exhibit n-type conductivity. The RBS analysis indicates the diffusion of the film material to the glass substrate. From Hall measurement it is confirmed that the film shows n-type conductivity and the resistivity decreases with increasing the annealing temperature. Highlights • Formation AgInSe 2 phase along with Ag 2 Se impurity phase by annealing of selenized Ag/In/Ag/In multilayers. • Films show n-type conduction with resistivity decreases with increasing the annealing temperature. • The suppression of the low band gap Ag 2 Se impurity phase on annealing at 500 ℃ led to an increase in the optical band gap. • The super-ionic α-Ag 2 Se diffuses Ag ion into tetrahedral sites which leads to the collapsing of Ag 2 Se phase. • The prepared AgInSe 2 films will act as ideal absorber material for the fabrication of solar cells. [ABSTRACT FROM AUTHOR]

Pure Na 0.5 Bi 0.5 TiO 3 (NBT), donor W 6+ doped NBT (NBTW), acceptor Ni 2+ doped NBT (NBTNi), as well as donor W 6+ and acceptor Ni 2+ codoped NBT (NBTWNi) polycrystalline films are fabricated on indium tin oxide (ITO)/glass substrates via a chemical solution deposition method. The roles of aliovalent-ion substitution on the crystallinity, ferroelectric and dielectric properties of NBT film are mainly investigated. With the introduction of aliovalent-ion, the surface of the doped film becomes more uniform and the leakage current is reduced. Well saturated polarization-electric field ( P-E ) loops can be observed in W 6+ and Ni 2+ codoped NBT film due to its lowest leakage currents compared to those of other films. Also, the effect of voltage and frequency on the capacitance-voltage ( C-V ) curve and the dielectric tunability for the NBTWNi film is discussed. The ferroelectric and dielectric properties are largely improved in NBTWNi film, which can be ascribed to the synergetic effect of high-valence W 6+ and low-valence Ni 2+ ions. The cooperation between the acceptor and donor cations can effectively eliminate the mobile oxygen vacancies in NBT films. [ABSTRACT FROM AUTHOR]

Zn acceptor/Ge donor (Zn/Ge)-codoped GaN films with different Zn contents have been deposited on Si substrates at 300 °C and at 90–150 W by RF reactive sputtering technique with cermet targets at the composition atomic ratios of Zn:Ge:(Ga+GaN) at x :0.03:(0.97- x ) with x  = 0, 0.03, 0.06, and 0.09 and Ga:GaN = 3:7. The films made with such targets were presented in an abbreviated symbol of Zn- x -GeGaN at x  = 0, 0.03, 0.06, and 0.09. The morphology, structure, electrical properties, optical property, and hetero-junction diode devices involved in the Zn- x -GeGaN films were thoroughly investigated. The systematic Zn increment into the n -type Zn-0-GeGaN through property evaluation provides the supporting information in studying solid solutioning. Zn- x -GeGaN films converted into p -type semiconductor at x  = 0.06 and 0.09. The values of bandgap were in the range of 2.87–3.17 eV with the lower value for the higher Zn content in Zn- x -GeGaN films. The higher RF power led to the faster growth, highly deficient in nitrogen, and a higher Zn atom ratio in the deposited film. The 120W-deposited Zn-0.06-GeGaN film had hole concentration of 7.21 × 10 16 cm −3 , hole mobility of 39.1 cm 2 V −1 s −1 , and the electrical conductivity of 0.45 S/cm. [ABSTRACT FROM AUTHOR]

Perovskite Na 0.5 (Bi 1−x Nd x ) 0.5 TiO 3 (x = 0, 0.01, 0.03, 0.05; xNd: NBT) ferroelectric films were synthesized on indium tin oxide (ITO)/glass substrates via chemical solution deposition. Structural characterization shows the similar phase-pure perovskite structures in all the films and gradually decreased grain sizes with Nd 3+ doping amount increasing. For all the films, the leakage behaviors are dominant by the Ohmic conduction in low electric field region and interface-limited Fowler-Nordheim tunneling mechanism in high electric field region. Additionally, the space-charge-limited conduction is involved in 0.03Nd: NBT sample. Compared with the sample of x = 0, the resistivity can be improved through Nd 3+ -substitution in NBT. Enhanced ferroelectricity can be obtained from the dynamic polarization-electric field test, and the reversible domains switching in film can be confirmed by static dielectric constant-electric field measurement. Especially, the 0.03Nd: NBT possesses optimal electrical performances with a large remanent polarization ( P r = 26.7 μC/cm 2 ) and a high dielectric tunability (19.6% at 100 kHz). [ABSTRACT FROM AUTHOR]

The Ge- x -GaN thin films were grown on Si (100) substrates by RF reactive sputtering technology with single cermet targets at the Ge/(Ge + Ga) molar ratios of x = 0, 0.03, 0.07 and 1. The Ge- x -GaN films had a wurtzite structure with a preferential ( 10 1 ¯ 0 ) plane. The SEM images showed that Ge-GaN films were smooth, continuous, free from cracks and holes, and possessed grains in nanometer-size. All Ge- x -GaN films remained as n-type. While the highest conductivity was found to be 1.46 S cm −1 in Ge-0.03-GaN film due to the highest carrier concentration of 2.55 × 10 18 cm −3 . Additionally, we made the n / p diodes with Ge-doped GaN films as n-type layers deposited on Si (100) substrate as p-type layer using by RF reactive sputtering technique. Their electronics characteristics were evaluated in terms of the barrier height, ideality factor, and series resistance. [ABSTRACT FROM AUTHOR]

Oxygen-deficient zinc oxides thin films with different levels of defects were prepared by using radio frequency magnetron sputtering method with sintered zinc oxide disk as target at different sputtering powers. The composition, structure and electrical properties of the prepared films were investigated. Under the present conditions, all the obtained films possessed würtzite structure, which were growing preferentially along the -axis. The thickness of the films, the size of the zinc oxide grains and the content of Zn atoms increased with increasing sputtering power. In the films deposited at a sputtering power from 52W to 212W, the main defect was interstitial zinc. With increasing sputtering power, due to the enhanced number of interstitial zinc in the films, their room-temperature electrical resistivity would decrease, which was controlled by electron conduction. At increasing measurement temperature, their electrical resistivity would increase, owing to the decrease of defect concentration caused by oxidization. [ABSTRACT FROM AUTHOR]

Novel indium-doped brookite phase TiO 2 films with different In concentrations were successfully prepared on the yttria-stabilized zirconia (YSZ) (110) substrates by the metal organic chemical vapor deposition (MOCVD) technique. The structural, morphological, electrical and optical properties of the films were investigated in detail. X-ray diffraction analysis revealed that all the films with different In concentrations were pure brookite phase TiO 2 with only one orientation along the b-TiO 2 (120) direction. The resistivity of the films was reduced by almost eight orders of magnitude by In doping with the lowest resistivity of 7.4 × 10 −2 Ω⋅cm and a mobility of 8.3 cm 2 V −1 s −1 obtained for the 2.6% In-doped b-TiO 2 film. The average optical transmittance of the 2.6% In-doped sample exceeded 74% in the visible range and the optical band gap was about 3.60 eV. [ABSTRACT FROM AUTHOR]

AlInGaN films were deposited at a substrate temperature in the range of 100-400°C and a radio frequency (RF) output power in the range of 90-150 W on Si (100) by reactive sputtering in an (Ar + N) atmosphere. A (Ga + GaN) cermet target for sputtering, containing 5 at.% aluminum and 7.5 at.% indium powders, was made by hot pressing the mixed metal powders and ceramic GaN. The effects of substrate temperature and sputtering output power on the formation of AlInGaN films and their electrical and optical properties were investigated. X-ray diffraction results showed that AlInGaN films grew with a preferential m-( $$10\bar{1}0$$ ) growth plane and had a wurtzite crystal structure. The film roughness was influenced by the sputtering power and the film composition. The AlInGaN films deposited at 400°C and 150 W had the best crystallinity, and an electron concentration of 4.5 × 10 cm, a Hall mobility of 497 cm V s, and an optical bandgap ( E ) of 2.71 eV. [ABSTRACT FROM AUTHOR]

Tin (Sn) doping in gallium nitride (GaN) has been mainly reported from the theoretical view only. Based upon the availability of Sn precursor and commercialization, Sn-GaN film has not been deposited magnetron sputtering until this work. By using the cheap and safe reactive sputtering technique, here we present Sn-GaN thin films with single cermet targets at the Sn/(Sn+Ga) molar ratios of x =0, 0.03, 0.07, and 0.1 to form Sn- x -GaN films under the atmosphere of the mixture of Ar and N 2 . The Sn-GaN films had the wurtzite structure. Sn can be added to GaN to form SnGaN alloy with a maximal amount of ~10%. The structural, electrical, and optical properties had changed with the Sn content until the oversaturation of Sn in Sn-0.1-GaN. The Sn doping led to the lattice expansion, worsened crystallinity, n-type GaN, increased electrical concentration, decreased the electrical mobility etc. Moreover, n -Sn- x- GaN/p-Si diodes were successfully made and their performance was evaluated in terms of the barrier height, ideality factor, and series resistance. This work has opened the door for studying the different kinds of dopants on the important III nitrides. [ABSTRACT FROM AUTHOR]

Cu 2 ZnSnS 4 (CZTS) is a promising material for thin film solar cell applications. On the other hand, spray pyrolysis technique has been identified as a low cost and versatile technique which could reduce cost per watt peak of panels. In this work, the sprayed-CZTS thin films are fabricated at substrate temperature in the range of 340–420 °C. The substrate temperature influence on the structural, morphological, electrical and optical properties is evaluated. It is found that CZTS thin films grown under 390 °C and thermally treated are the most appropriate for solar cell applications. CZTS thin films with Cu/(Zn + Sn) and Zn/Sn compositional ratios near to the optimal ones are achieved. Finally, resistivity, Hall mobility and carrier density values in the range of 0.5–80.2 Ω·cm, 0.6–10.3 cm 2 /Vs and 2.2 × 10 17 –7.0 × 10 18 cm − 3 , respectively, are reported. [ABSTRACT FROM AUTHOR]

By reactive sputtering in an atmosphere mixed with Ar and N 2 , AlInGaN films were deposited from Al 0.05 In x Ga 0.95−x N (x= 0.075 , 0.15 and 0.25) targets on Si (100) with a substrate temperature of 200 °C and a radio-frequency (RF) output power of 120 W. Hot pressing was used to create a series of cermet targets mixed with metal powders and ceramic GaN for sputtering. The AlInGaN films demonstrate a wurtzite crystalline structure with a preferential m -( 10 1 ¯ 0 ) growth plane. We investigated the effect of compositional changes on the formation of the AlInGaN film and its electrical and optical properties. Then, I-V measurements were conducted on a straightforward n -AlInGaN/p-Si heterostructure diode, with the device containing the film deposited from the Al 0.05 In 0.075 Ga 0.875 N target exhibiting the highest turn-on voltage of 9.2 V and the lowest leakage current of 6.65×10 −9 A (at −5 V). [ABSTRACT FROM AUTHOR]

[Display omitted] • BST/MTO bi-layer exhibited better structural stability than that of MTO/BST bi-layered film. • Stacking order played a significant role in heterostructure growth. • The effective dielectric constant for BST/MTO bilayer film is intermediate to MTO and BST dielectric constant. • Both Schottky emission and space-charge limited current contribute to leakage current. The structural, microstructural, electrical, and dielectric properties of MgTiO 3 (MTO)/ Ba 0.5 Sr 0.5 TiO 3 (BST) bi-layer structures grown by reactive RF magnetron sputtering have been reported. The films exhibited polycrystalline nature and the stacking of BST on MTO (BST/MTO) exhibited better crystallinity than that of MTO stacking on BST(MTO/BST). The RMS roughness for BST/MTO and MTO/BST is found to be 1.82 nm and 49.2 nm, respectively. The dielectric constant (ε r , ∼27.3) and loss tangent (tan δ , ∼10−2) at 100 kHz for BST/MTO are found to be intermediate to BST and MTO monolayer responses. The anomaly observed in dielectric response (ε r , ∼323.2 and tan δ , ∼10−2) for MTO/BST can be attributed to the generation of charge carriers in the interfaces of individual layers. The relation between electrically active regions with the observed electrical response is studied by impedance spectroscopy. The leakage in MTO/BST (10−2 A/cm2 at 100 kV/cm) bilayer is higher than that of BST/MTO (10−4A/cm2 at 100 kV/cm) bilayer and Schottky emission along with Space-charge limited current contribute to the leakage current. Both MTO/BST and BST/MTO films exhibited tunable dielectric responses. These findings of this report provide prospective insight into the design of multilayer structured smart materials. 1 1 MTO and BST bilayer films [ABSTRACT FROM AUTHOR]

The purpose of this work is to investigate the effects of deposition and post-deposition supercritical carbon dioxide (scCO 2 ) processing parameters on physical and electrical properties of pentacene thin films. Pentacene, a common polycyclic aromatic hydrocarbon, has been studied for its potential applications in organic thin film (OTF) transistors used for electronic devices, bio- and chemical sensors. One of the primary challenges is controlling thin film quality, which is driven by processing techniques. Here, organic vapor phase deposition was used to deposit OTF at three temperatures (623 K, 643 K, and 648 K) and two pentacene sources (singly-sublimed and triply-sublimed). The film surface was subsequently treated with benzene-1,4-diboronic acid (BDBA), in scCO 2 for further electrical property improvement. ScCO 2 film treatment was performed at 313 K and 323 K, for a nominal range of pressures, and with up to 5 mol% of methanol added as co-solvent. Results show that triply-sublimed pentacene deposited at a slower rate compared to singly-sublimed pentacene, especially at lower temperatures. Triply-sublimed pentacene films also exhibited a surface microtexture with more crystalline features and lower sheet resistivity after scCO 2 /methanol/BDBA treatment. BDBA sorption at the film surface depends on both film thickness and surface morphology, but not processing temperature alone. [ABSTRACT FROM AUTHOR]

The effects of annealing temperature on the structure, morphology, ferroelectric and dielectric properties of Na 0.5 Bi 0.5 Ti 0.99 W 0.01 O 3+ δ (NBTW) thin films are reported in detail. The films are deposited on indium tin oxide/glass substrates by a sol-gel method and the annealing temperature adopted is in the range of 560–620 °C. All the films can be well crystallized into phase-pure perovskite structures and show smooth surfaces without any cracks. Particularly, the NBTW thin film annealed at 600 °C exhibits a relatively large remanent polarization ( P r ) of 20 μC/cm 2 measured at 750 kV/cm. Additionally, it shows a high dielectric constant of 608 and a low dielectric loss of 0.094 as well as a large dielectric tunability of 62%, making NBTW thin film ideal in the room-temperature tunable device applications. [ABSTRACT FROM AUTHOR]

Multi-phase ternary oxide glass thin films of potassium antimony oxide were synthesized via dip coating (DC) and spray pyrolysis (SP) methods. The growth of thin film was conducted on a non-conductive borosilicate glass substrate. Surface morphology was investigated and showed different characteristics. X-ray diffraction (XRD) analysis revealed the peaks corresponded to the monoclinic KSb 3 O 5 and K 2 Sb 4 O 11 phases. The structural parameter analysis shows that the lower values of micro strain (ε), dislocation density (δ), and stacking fault probability (SF) with higher number (N) of particle in the multi-phase thin film for the spray pyrolysis method confirm slightly larger crystallite size, less crystal imperfection, and less structural disorder. The lower average transmission, absorption, and extinction coefficients resulted to higher refractive index, permittivity, and electrical susceptibility for the sample synthesized by a spray pyrolysis method. In addition, the average energy band gap values (E g) of 3.57 and 3.60 eV were obtained for the dip coating and spray pyrolysis methods, respectively. However, the lower R s (14.69 × 107 Ω/sq.) with higher σ h (85.09 S/cm) and the FOM (H-HR) (0.183 Ω-1) of the multi-phase K–Sb–O thin film for the dip coating method were obtained may be due to more interconnections generated at the interface and there are less residual on the surface of thin film. • Two synthesis methods were used for the multi-phase K–Sb–O thin films. • Structural and morphological parameters were investigated and compared. • Optical and electrical properties were also investigated and compared. • Reasonable E g were obtained from both dip coating and spray pyrolysis methods. • Spray pyrolysis method is more advantage for the synthesis of multi-phase K–Sb–O thin films. [ABSTRACT FROM AUTHOR]

Mg-doped InGaN (Mg-InGaN) films have been deposited directly on Si (100) substrates by radio-frequency reactive sputtering technique with single cermet targets in an Ar/N atmosphere. The cermet targets with a constant 5% indium content were made by hot pressing the mixture of metallic In, Ga, and Mg powders and ceramic GaN powder. The Mg-InGaN films had a wurtzite structure with a preferential ( $$ 10\bar{1}0 $$ ) growth plane. The SEM images showed that Mg-InGaN films were smooth, continuous, free from cracks and holes, and composed of nanometer-sized grains. As the Mg dopant content in Mg-InGaN increased to 7.7 at.%, the film was directly transformed into p-type conduction without a post-annealing process. It had high hole concentration of 5.53 × 10 cm and electrical mobility of 15.7 ± 4.2 cm V s. The over-doping of Mg in InGaN degraded the electrical properties. The bandgap of Mg-InGaN films decreased from 2.92 eV to 2.84 eV, as the Mg content increased from 7.7% to 18.2%. The constructed p-type Mg-InGaN/ n-type GaN diode was used to confirm the realization of the p-type InGaN by sputtering technique. [ABSTRACT FROM AUTHOR]

Abstract: Cu2ZnSnSe4 (CZTSe) and Cu2ZnSn(S,Se)4 (CZTSSe) films were prepared by sputtering of single metallic Cu–Zn–Sn target and subsequent selenization or sulfo-selenization at 550−650°C. Selenization aided by SnSe2 and CuSe2 obtained CZTSe with dense microstructure and large grain size of 8μm. Sulfo-selenization with SnSe2 and CuS pellets did not achieve large-grained CZTSSe. Substitution of Cu+ by Zn2+ to form ZnCu 1+ donor and occupation of Cu+ at the B site of Cu2 B I B II(S,Se)4 to form Cu B 2− acceptor are major defects that explain the relation between composition and electrical property, which are important material properties to evaluate CZTSe and CZTSSe films to be used as absorbers for solar cells. [Copyright &y& Elsevier]

[Display omitted] • Wrinkles allow films to cope with deformation while maintaining stable conductivity. • The Ag NPs, MWCNTs and Ag-MWCNTs mixture are studied separately. • During stretching, PU/Ag-MWCNTs show more stable conductivity than PU/Ag. • During stretch cycle, Ag are easier to reconstruct the damaged conductive path. Development of elastic conductive film is critical to prepare flexible electronic devices. Herein, bidirectional elastic conductive films based on polyurethane (PU) and different dimensional fillers were prepared by using an novel alternating stretching layer-by-layer self-assembly (AS-LBL) technology. It is shown that wrinkle structures were constructed in the conductive films, which allows them to cope with the deformation under bidirectional stretching to a certain extent, while maintaining stable conductivity. Basically, the one-dimensional MWCNTs exhibit the better construction speed of the conductive path than zero-dimensional Ag NPs. In addition, under the synergy of Ag NPs and MWCNTs, the conductivity of PU/Ag-MWCNTs films reaches the best. After adsorbing 6 layers of Ag-MWCNTs, the conductivity of the film increased to 0.24 S cm−1. More importantly, during the stretching process, the PU/MWCNTs and PU/Ag-MWCNTs films show a more stable conductivity than PU/Ag. As the strain increases from 0 to 500%, the conductivity of PU/Ag-MWCNTs films decreases by only 9.6%. However, during the stretch-release cycle, the zero-dimensional small-sized Ag NPs display a more superior ability of conductive path reconstruction than MWCNTs. When the elongation is 100%, after 100 stretching cycles, the conductivity of PU/Ag film is only reduced by 8%. [ABSTRACT FROM AUTHOR]

Abstract: The dependences of electrical and structural properties on film thickness below 100 nm have been studied on polycrystalline undoped zinc oxide (ZnO) thin films on glass substrates at 200 °C prepared by plasma-assisted electron-beam deposition. From Hall effect measurements, we find that resistivity decreases from 0.47 to 0.02 Ω cm with increasing film thickness, whereas carrier concentration remains almost constant, 1.65–2.0×1019 cm−3, Hall mobility increases from 1.7 to 16.7 cm2/Vs with increasing film thickness. From both high-resolution out-of-plane and in-plane X-ray diffraction (XRD) data, we find substantial changes in the lattice parameters with increasing film thickness below 40 nm; a reduction in the lattice parameter of the a-axis and an increase in the lattice parameter of the c-axis. Williamson–Hall analysis reveals an increase in in-plane grain size with increasing film thickness. This indicates that the dominant scattering mechanism that determines electrical properties is a boundary scattering mechanism. [Copyright &y& Elsevier]

Abstract: HfO2 dielectric layers were grown on the p-type Si(100) substrate by metal-organic molecular beam epitaxy (MOMBE). Hafnium-tetra-butoxide [Hf(O·t-C4H9)4] was used as a Hf precursor and argon gas was used as a carrier gas. The microstructure and thickness of HfO2 films were measured by scanning electron microscopy (SEM) and high-resolution transmission electron microscopy (HRTEM). The electrical characteristics of the HfO2 layers were evaluated by high frequency (HF) capacitance–voltage (C–V) and current–voltage (I–V) measurements. The surface morphology, crystal structure, and chemical binding states of HfO2 films were also examined by atomic force microscopy (AFM), X-ray diffraction (XRD), and X-ray photoelectron spectroscopy (XPS) measurements. HF C–V and I–V measurements have shown that HfO2 layer grown by MOMBE has higher dielectric constant (k) of 20–22 and lower leakage current density of ∼10−8 A/cm2 compared with the conventional SiO2. In addition, it has been shown that the HfO2 layer has fixed oxide charge of about 8×1011 cm−2 and interfacial state density of about 1×1012 eV−1 cm−2. The electrical characteristics and surface morphology of HfO2 films are affected by O2/Ar gas flow ratio. Finally, post-metallization annealing (PMA) was carried out to reduce the interface state density. [Copyright &y& Elsevier]

Radiation damages due to 8 MeV electron irradiation in electrical properties of CuInSe2 thin films have been investigated. The n-type CuInSe2 films in which the carrier concentration was about 3×1016 cm−3, were epitaxially grown on a GaAs(0 0 1) substrate by RF diode sputtering. No significant change in the electrical properties was observed under the electron fluence <3×1016 e cm−2. As the electron fluence exceeded 1017 e cm−2, both the carrier concentration and Hall mobility slightly decreased. The carrier removal rate was estimated to be about 0.8 cm−1, which is slightly lower than that of III–V compound materials. [Copyright &y& Elsevier]

Transparent conducting oxide (TCO) thin film is a key component of photoelectric devices for extensive applications. Exploring new TCO films with high electronic conductivity, high transmittance and low cost is urgently required. Here, the wurtzite structured Ge-doped ZnO thin films were deposited on the glass substrates by using a pulsed laser deposition method. The effects of Ge-doping concentration, glass substrate temperature and oxygen partial pressure on crystallinity, surface morphology, electrical conductivity and visible light optical transmittance of the thin films were studied systematically. It is revealed that the preferred orientation of the film can be controlled by oxygen partial pressure. Under the optimized deposition conditions of Ge-doping amount of 2.0 at.%, glass substrate temperature of 300 °C and oxygen partial pressure of 1.5 Pa, it was found that the prepared ZnO:Ge thin films with a thickness of 95 nm could display an electrical resistivity as low as 6.10 × 10−4 Ω cm and had a high transmittance of 92.3% in the visible region, proving that ZnO:Ge thin film is a promising TCO material. • The relationship between preparation conditions and photoelectric properties of ZnO:Ge film is revealed. • Preferred orientation of the film can be controlled by oxygen partial pressure. • The optimized ZnO:Ge film exhibited outstanding electric and optical properties. [ABSTRACT FROM AUTHOR]