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When Nd doping in BiNdFeO (BNFO) film exceeds 10%, the two diffraction peaks (104)/(110) merge into one sharp single peak with increasing addition of Nd. It seems that a phase structural distortion can be obtained due to the substitution of Nd3+ ion for Bi3+ ion. For ferroelectric properties, among all Nd-doped (0%–20%) BiFeO3 capacitors, the BNFO capacitor with 10% Nd doping shows a higher Pr value due to a phase structural distortion and a lower leakage current. In a resistive-capacitive circuit diagram, the transient response of the voltage (V FE) across the BNFO capacitor can be measured. We demonstrate that the capacitance value d Q t d V FE t is negative in the spike interval of V FE(t), with the result that the negative capacitance of BNFO with a 10% Nd doping capacitor can obviously improve the I DS–V GS characteristics of a control thin-film transistor.

Nowadays, the development of GPS (Global Positioning System) technology has become mature, and has begun to develop in the direction of high-precision positioning and navigation. Navigation data such as position, speed, and heading provided by GPS are very important in military or commercial fields. However, in addition to improving the accuracy of positioning, its reliability must also be considered. Therefore, RTK (Real Time Kinematic) differential positioning technology is used to perform real-time error correction and basic inertial components consist of gyroscope, accelerometer, and magnetic compass are used to compensate and improve reliability. In this study, a car is used as a vehicle to experiment the route near the campus. The collected XYZ position coordinate data of the non-difference, differential positioning, and original vehicle are calculated by MATLAB offline operation to obtain $\lambda($longitude), $\Phi$ (latitude), h (height), and the data sensed by integrated inertial elements in the GPS signal shaded roads as auxiliary navigation, and then compare it with the existing and non-differential positioning methods to obtain a more optimized drawing path. The map achieves the compensation effect. In this study, the position of the shaded road is obtained by the second integration of the gyroscopic azimuth change and the heading angle of the magnetic compass through the accelerometer signal. The Extended Kalman Filter algorithm is used as its solution to estimate position, speed and heading of the vehicle in real time to achieve high accuracy and high reliability of real-time positioning and navigation.

Bi1-xMgxFeO3 (BMFO, x = 0, 0.02, 0.04, 0.06 and 0.08) multiferroic films were directly synthesized on flexible stainless steel (FSS), save the bottom electrode process, by means of sol&ndash, gel spin-coating technology. The effects of different bending conditions on ferroelectric, dielectric and leakage-current properties of BMFO films were investigated. The leakage-current densities of BiFeO3 (BFO, x = 0) and BMFO (x = 0.06) films were 5.86 &times, 10&minus, 4 and 3.73 &times, 7 A/cm2, which shows that the BMFO (x = 0.06) has more than three orders of magnitude lower than that of BFO film. The residual polarization (2 Pr) can be enhanced from 120 to 140 &mu, C/cm2. The proper doping of Mg in BiFeO3 film could provide an effective method for reducing the leakage-current values as well as boosting the ferroelectric properties. In this study, the leakage-current mechanism of low electric field and high electric field of BMFO film is analyzed and established. In addition, the flexible BMFO film maintains practical ferroelectric and leakage-current properties at retention time of 106 s under different symmetry bending conditions. These results indicate that the BFMO film will be very practical in opto-electronic and storage device applications.

Zn1&minus, xMgxO (x = 0, 0.03, 0.05, and 0.07) nanocrystalline films were grown on silicon substrates using the sol&ndash, gel method. Furthermore, Zn1&minus, xMgxO vertically aligned hexagonal symmetrical nanorods with six reflection symmetries were fabricated on pure ZnO-seeded layer n-type silicon substrates via a low-temperature hydrothermal method to enhance the ultraviolet (UV) light response. The crystal microstructures and surface morphologies of nanocrystalline films and nanorod arrays were determined by X-ray diffraction (XRD) and field emission scanning electron microscopy (FE-SEM). Transmission spectra showed that the increasing Mg content will increase the band gap energy from 3.28 to 3.46 eV. However, the current&ndash, voltage curves in the dark and under UV illumination showed that the UV response did not improve by the incorporation of magnesium. We changed the flat surface of films into symmetrical nanorod arrays and demonstrated they can significantly enhance the normalized photo-to-dark-current ratio up to ten times.

In this study, the Mg doping effects on the nanostructural dependence of photoluminescence and the photosensing properties in Zn1−xMgxO (x = 0.01, 0.03, and 0.05) nanorod arrays were systematically examined. The vertical-aligned nanorod arrays were separately grown on ZnO-seeded n-Si substrates via a low-temperature hydrothermal process. X-ray diffraction analysis revealed that all Zn1−xMgxO nanorod arrays exhibited the same preferentially c-oriented wurtzite structure. Images of all the Zn1−xMgxO nanorod arrays provided by field emission scanning electron microscope showed that both the length and diameter of the Zn1−xMgxO nanorod arrays increased with increasing Mg doping concentration. Also, an enhanced blue-shifted ultraviolet (UV) emission and a reduced visible emission were observed from the photoluminescence spectra of the Zn1−xMgxO nanorod arrays. The former indicated the decrease of defects and the latter indicated the enhancement of the crystallinity and the increase in optical bandgap. Current–voltage curves were separately measured in the dark and under UV illumination. Finally, the mechanism of the Mg doping effects on the corresponding defects, bandgap, and UV photosensing characteristics of the Zn1−xMgxO nanorod arrays was investigated in detail.

By a sol–gel method, a BiFeO3 (BFO) capacitor is fabricated and connected with the control thin film transistor (TFT). Compared with a control thin-film transistor, the proposed BFO TFT achieves 56% drive current enhancement and 7–28% subthreshold swing (SS) reduction. Moreover, the effect of the proposed BiFeO3 capacitor on IDS-VGS hysteresis in the BFO TFT is 0.1–0.2 V. Because dVint/dVGS > 1 is obtained at a wide range of VGS, it reveals that the incomplete dipole flipping is a major mechanism to obtain improved SS and a small hysteresis effect in the BFO TFT. Experimental results indicate that sol-gel BFO TFT is a potential candidate for digital application.

Electrical conduction mechanism and bipolar resistive switching properties of the manganese oxide thin films resistive random access memory (RRAM) devices for high resistive status and low resistive status (HRS/LRS) were investigated and discussed. The electrical and physical properties of post-treatment manganese oxide thin films for different oxygen concentration parameters were measured by x-ray diffraction (XRD) and operation current versus applied voltage ( I-V ) measurement. For I-V curves in different temperature, the ohmic conduction, space charge limited conduction (SCLC), schottky emission conduction, and hopping conduction mechanism of manganese oxide RRAM devices were discussed and verified in initial metallic filament path forming process. Finally, the excess oxygen ions, vacancy, and defect factor resulting in bipolar and unipolar resistive switching behavior of thin films RRAM devices will be explained and investigated by metallic filament path forming model.

GaAs p-i-n solar cells are studied using electroreflectance (ER) spectroscopy, light beam induced current (LBIC) mapping and photovoltaic characterization. Using ER measurements, the electric field across the pn junction of a wafer can be evaluated, showing 167 kV/cm and 275 kV/cm in the built-in condition and at &minus, 3 V reverse bias, respectively. In order to understand the effect of the interval between metal grids on the device&rsquo, s solar performance, we performed LBIC mapping and solar illumination on samples of different grid spacings. We found that the integrated photocurrent intensity of LBIC mapping shows a consistent trend with the solar performance of the devices with various metal grid spacings. For the wafer used in this study, the optimal grid spacing was found to be around 300 &mu, m. Our results clearly show the importance of the metal grid pattern in achieving high-efficiency solar cells.

The bipolar switching properties and electrical conduction mechanism of vanadium oxide thin-film resistive random-access memory (RRAM) devices obtained using a rapid thermal annealing (RTA) process have been investigated in high-resistive status/low-resistive status (HRS/LRS) and are discussed herein. In addition, the resistance switching properties and quality improvement of the vanadium oxide thin-film RRAM devices were measured by x-ray diffraction (XRD) analysis, x-ray photoelectron spectrometry (XPS), scanning electron microscopy (SEM), atomic force microscopy (AFM), and current–voltage (I–V) measurements. The activation energy of the hopping conduction mechanism in the devices was investigated based on Arrhenius plots in HRS and LRS. The hopping conduction distance and activation energy barrier were obtained as 12 nm and 45 meV, respectively. The thermal annealing process is recognized as a candidate method for fabrication of thin-film RRAM devices, being compatible with integrated circuit technology for nonvolatile memory devices.

Pr-doped ZnO thin films (Zn1−xPrxO) (x = 0.00, 0.01, 0.02, 0.04) were prepared on fluorine-doped tin oxide substrates by means of the sol–gel method and spin coating technology, followed by rapid thermal annealing treatment at 800 °C. The influence of Pr content on the structural and optical properties of the Zn1−xPrxO thin film was examined and discussed. The wurtzite hexagonal structural characteristics were investigated by X-ray diffraction analysis, and Pr3+ substitution for Zn2+ ions was indicated. Finally, the typical bipolar current-voltage switching curves and electrical conduction model of Zn1−xPrxO film resistive random access memory devices were discussed and investigated for low resistance state/high resistance state in the initial forming process.

FeS2 pyrite films are used in a variety of applications including solar cells and, the potential scope for their utilization is increasing as their synthetic methods become more economical while maintaining or enhancing their high light absorption coefficients. The glass substrate temperature dependence on the formation of FeS2 pyrite films was investigated with respect to their optical and physicochemical properties. During the thermochemical spraying process the temperature was varied in the range of 190-290 °C. FeS2 nanocrystalline (40-70 nm) films, formed as a result of atmospheric spraying with glass substrate temperatures above 260 °C, were observed by SEM. Opto-electronic studies revealed that the nanocrystalline films had a direct band gap (1.3-1.6 eV) with a high light absorption coefficient (α > 7 × 104 cm−1 for λ

Indium tin oxide (ITO; Indium oxide with tin doping) nanowires were first prepared via the electrochemical deposition and an oxidization method based on an AAO template. FE-SEM results show the synthesized ITO nanowires to have an approximate length of 8–10 μm with an aspect ratio close to 167. ITO nanowires with an In/Sn weight ratio of 8.8 (∼9:1) were observed from EDS. The crystal structure of ITO nanowires showed that all the peaks within the spectra can be indexed to In2O3 with a cubic structure. The ITO nanowire is single-crystalline determined from selected area electron diffraction (SAED) patterns. An optical energy gap (Eg) of the ITO nanowire is 3.8 eV.

Bi0.9Gd0.1FeO3 (BGFO) thin films were fabricated on Pt(111)/Ti/SiO2/Si(100) substrates by using the sol–gel technology. The effects of annealing temperature (400–700 °C) on microstructure and multiferroic properties of thin films were investigated. The X-ray diffraction analysis showed that the BGFO thin films had an orthorhombic structure. The thin films showed ferroelectric and ferromagnetic properties with remanent polarization (2Pr) of 10 μC/cm2, remnant magnetization (2Mr) of 2.4 emu/g and saturation magnetization (Ms) of 5.3 emu/g. A small leakage current density (J) was 4.64×10−8 A/cm2 under applied field 100 kV/cm. It was found that more than one conduction mechanism is involved in the electric field range used in these experiments. The leakage current mechanisms were controlled by Poole–Frenkel emission in the low electric field region and by Schottky emission from the Pt electrode in the high field region.

Bipolar resistive switching properties and endurance switching behavior of the neodymium oxide (Nd2O3) thin films resistive random access memory (RRAM) devices for a high resistive status/low resistive status (HRS/LRS) using a low temperature supercritical carbon dioxide fluid (SCF) improvement post-treatment process were investigated. Electrical and physical properties improvement of Nd2O3 thin films were measured by X-ray diffraction (XRD), scanning electron microscopy (SEM), X-ray photoelectron spectroscopy (XPS), and current versus voltage (I-V) measurement. The metal-like behavior of ohmic conduction mechanism and metallic cluster reaction of hopping conduction mechanism in initial metallic filament path forming process of the SCF-treated thin films RRAM devices was assumed and discussed. Finally, the electrical conduction mechanism of the thin films RRAM derives for set/reset was also discussed and verified in filament path physical model.

Bi0.8Pr0.2Fe0.95Mn0.05O3/Bi3.96Gd0.04Ti2.95W0.05O12 (BPFMO/BGTWO) bilayer thin films with Multiferroic/Ferroelectric (MF/FE) structures were deposited onto Pt(111)/Ti/SiO2/Si(100) substrates by using the sol-gel method with rapid thermal annealing. The BPFMO/BGTWO thin films exhibited well-saturated ferromagnetic and ferroelectric hysteresis loops because of the electro-magnetic coupling induced by the MF/FE structure. The remnant magnetization (2Mr) and remnant polarization (2Pr) were 4.6 emu/cm3 and 62 μC/cm2, respectively. Moreover, the bipolar I-V switching curves of BPFMO/BGTWO bilayer thin films resistive random access memory (RRAM) devices were discussed, and investigated for LRS/HRS.

Praseodymium and niobium-substituted bismuth titanate (Bi 3.96 Pr 0.04 Ti 2.95 Nb 0.05 O 12 , BPTNO) thin films were deposited on Pt(111)/Ti/SiO 2 /Si(100) substrates by a sol–gel technology. The effects of annealing temperature (500 ~ 800 °C) on microstructure and electric properties of thin films were investigated. X-ray diffraction analysis shows that the BPTNO thin films have a bismuth-layered perovskite structure with preferred (117) orientation. The intensities of (117) peak increases with increasing annealing temperature. With the increase of annealing temperature from 500 °C to 800 °C, the grain size of BPTNO thin films increases. The highly (117)-oriented BPTNO thin films exhibits a high remnant polarization (2 P r ) of 48 μC/cm 2 and a low coercive field (2 E c ) of 110 kV/cm, fatigue free characteristics up to > 10 8 switching cycles. A small leakage current density ( J ) was 6.23 × 10 − 8 A/cm 2 at 200 kV/cm. The leakage current mechanisms were controlled by Poole–Frenkel emission in the low electric field region and by Schottky emission in the high field region.

Surface plasmon resonance mediated by Gold (Au) nanoparticles (NPs) was employed to enhance the ultraviolet (UV) response of p-Si/n-ZnO nanorod (NR) heterojunction photodetectors (HPDs). In the ZnO NRs with Au NP covering, the photoluminescence spectrum shows that the band-to-band emission of ZnO (384 nm) is increased by a magnitude of 3, and the deep-level emissions (450-700 nm) are drastically decreased as compared with HPDs without coverings of Au NPs. Such a result increases UV-to-visible rejection ratio from 214 to 6180 and it attributes that the defect-level emissions of ZnO induce surface plasmon resonance in Au NPs and then enhances the emissions, exciting a large quantity of electrons crossing over the Au NP/ZnO interface barrier. Consequently, these electrons are transferred to the ZnO conduction band from the Au NPs, causing a photocurrent gain and the quantum efficiency is as high as 1157% at 2 V reverse bias.

ZnO and Y-doped ZnO nanocrystalline films were separately fabricated on the glass substrates by sol-gel spin-coating method. X-ray diffraction patterns of the films show the same wurtzite hexagonal structure and (0 0 2) preferential orientation. Scanning electron microscope images show that grain size and thickness of the nanocrystalline films decrease with increasing doping concentration. The decrease of optical bandgap with the increase of Y doping is deduced from the transmittance spectra. Temperature-dependent resistivity reveals a semiconductor transport behavior for all ZnO and Y-doped ZnO nanocrystalline films. The resulting conductivity originates from the combination of thermal activation conduction and Mott variable-range hopping (VRH) conduction. In the high-temperature range, the temperature-dependent resistivity can be described by the Arrhenius equation, ${\sigma}$ $(T)$ = ${\sigma}_{0}$ exp[ $-(E_{a}$ /kT)], which shows the thermal activation conduction. The activation energy $E_{a}$ increases from 0.47 meV for ZnO film to 0.83 meV for Zn $_{0.98}$ Y $_{0.02}$ O film. On the contrary, in the low-temperature range, the temperature-dependent resistivity can be fitted well by the relationship, ${\sigma}$ ( $T)$ = ${\sigma}_{h}$ $_{0}$ exp[ $-(T_{0}$ / $T)$ $^{1/4}$ ], which indicates the behavior of Mott VRH. The results demonstrate that the crystallization and the corresponding carrier transport behavior of the ZnO and Y-doped ZnO nanocrystalline films are affected by Y doping.

The transparent ZnO and Zn0.96Fe0.04O nanocrystalline films were deposited on the glass substrates by sol–gel method followed by repaid thermal annealing treatment. The grain size of the ZnO films was decreased by the doping of Fe. X-ray diffraction measurements of the films showed the same wurtzite hexagonal structure and preferential orientation along the c-axis. Temperature dependence resistivity showed a semiconductor transport behavior for both compositions. At high temperature region, the transport mechanism can be fitted with semiconductor behavior by Arrhenius equation, σ(T) = σ0 exp[−(Ea/kT)m] with m = 1. The activation energy Ea is increased from 0.47 meV for pure ZnO film to 0.69 meV for Zn0.96Fe0.04O film obtained from equation. At low temperature region, the resistivity can be fitted well with the behavior of Mott variable range hopping, σ(T) = σh0 exp[−(T0/T)n] with n = 1/4. The results demonstrate that the crystallization and the corresponding carrier transport behavior of the Zn1 − xFexO films are affected by the doping of Fe in the Zn1 − xFexO films.

In this paper, the chalcopyrite CuInSe2 thin films were fabricated from a selenization of electrodeposited Cu-In layers. In this study, the electrodeposition time of the In layer was set, but that for the Cu layer was not. The thin films were selenized in a sealed glass tube with pure Se powder by three different Cu layer samples at various electrodeposition times at 500 °C for 2 hours. An FE-SEM image of the sample shows that the copper-rich product has irregular agglomerates with a dense surface. The X-ray diffraction patterns show CuInSe2 peaks for all samples. However, the X-ray diffraction pattern reveals CuSe2 peaks when the electrodeposition time of the Cu layer increases. On the other hand, the band gap (Eg) of the samples decreases from 1.15 to 1.07 eV when the Cu/In ratio increases.

Sm–Ta co-doped Bi 4 Ti 3 O 12 (Bi 3.96 Sm 0.04 Ti 2.92 Ta 0.08 O 12 , BSTTO) thin films were fabricated on Pt(111)/Ti/SiO 2 /Si(100) substrates by sol–gel technology, and the microstructure, dielectric, ferroelectric and leakage current properties of the thin films were investigated. BSTTO thin film exhibits a high remanent polarization (2 P r ) of 46.2 μC/cm 2 and a low coercive field (2 E c ) of 102 kV/cm, fatigue-free characteristics up to ≧ 10 8 switching cycles. The 2 P r of the BSTTO thin film is larger than that of the Bi 4 Ti 3 O 12 thin film (2 P r = 26 μC/cm 2 ). In addition, the leakage current density of Sm–Ta co-doped Bi 4 Ti 3 O 12 thin film is 2.56 × 10 − 8 A/cm 2 , which is lower than that of the Bi 4 Ti 3 O 12 thin film (1.0 × 10 − 5 A/cm 2 ). These improvements in the ferroelectric and leakage current properties can be attributed to the enhanced stability of the oxygen in the Ti–O octahedron layer by the substitution with Sm and Ta for Bi 3 + and Ti 4 + in A-site and B-site of the BTO thin film, respectively.

Herein one-dimensional Sm-doped ZnO nanostructures have been successfully fabricated by a simple hydrothermal method at a low temperature of 90 � C. The effect of Sm doping on the microstructure, photoluminescence and magnetism of ZnO nanorods is also investigated. FE-SEM images show that the average diameter of the Sm-doped ZnO nanorods is obviously smaller than that of ZnO nanorods. Photoluminescence spectrum of Sm-doped ZnO nanorods shows a slightly red-shifted decrease of UV emission and an enhancement of photoluminescence performance of visible emission. Raman spectrum of Sm-doped ZnO nanorods reveals that the peak intensity corresponding to the E2 high mode decreases significantly compared with that of the pure ZnO nanorods, indicating the restraint of crystallization. Room temperature ferromagnetism is observed from magnetization curves of both ZnO and Sm-doped ZnO nanorods. The increase of the saturation magnetization induced by the Sm doping in the ZnO nanorods reveals an association with the increase of oxygen vacancies and oxygen interstitials.

Herein transparent Zn1-xFexO nanocrystalline films have been prepared on glass substrates by sol-gel method followed by rapid thermal annealing treatment. The effecs of Fe doping on the microstructure, transmittance and magnetism of Zn1-xFexO nanocrystalline films are investigated. The x-ray diffraction patterns of all compositions show the same wurtzite hexagonal structure with the space group P63/mc. FE-SEM images show uniform spherical grains of all Zn1-xFexO nanocrystalline films in which the grain size decreases progressively from 38.85 nm (x = 0.00) to 15.35 nm (x = 0.04). Red shift of the absorption edges is obtained from the optical transmittance spectra from 372 nm of undoped ZnO film to 367 nm of Zn0.96Fe0.04O film. The corresponding wide band gap energy of undoped ZnO film is 3.2986 eV which decreases slightly by 0.0191 eV of Zn0.96Fe0.04O film. The saturation magnetization increases with the increase of Fe concentration. All Fe-doped ZnO films exhibit feromagnetic hysteresis curves which can b...

Tantalum-substituted Bi4Ti3O12 (Bi4Ti3-x/5Tax/5O12, BTTO) thin films were fabricated on Pt(111)/Ti/SiO2/Si(100) substrates by sol–gel technology. The effects of various processing parameters, including Ta content (x=0∼0.08) and annealing temperature (500∼800 °C), on the growth and properties of thin films were investigated. X-ray diffraction analysis shows that the BTTO thin films have a bismuth-layered perovskite structure with preferred (117) orientation. With the increase of Ta content, the grain size of film decreased slightly, and highly (117)-oriented BTTO films were obtained in the composition of x=0.06. Ta doping on the B-site of Bi4Ti3O12 could induce the distortion of oxygen octahedral and decrease the oxygen vacancy concentration by a compensating effect. The highly (117)-oriented BTTO thin films with x=0.06 exhibits the maximum remanent polarization (2Pr) of 50 μC/cm2 and a low coercive field (2Ec) of 104 kV/cm, fatigue free characteristics up to ≧ 108 switching cycles.

The Bi0.85 Eu0.15 FeO3 /Bi3.2 Y0.8 Ti3 O12 bilayer thin films were prepared on Pt(111)/Ti/SiO 2/Si(100) substrates using the sol-gel process and annealed by rapid thermal annealing in various annealing environments (ambient atmosphere and oxygen). The multiferroic/ferroelectric bilayer thin films were composed of 0.8-μ m thickness Bi0.85 Eu0.15 FeO3 and 0.2-μ m thickness of Bi3.2 Y0.8 Ti3 O12 thin film. The effects of annealing atmospheres (ambient atmosphere and oxygen) on the growth and properties of thin films were investigated. The results show that the intensities of the (117) diffraction peak of Bi3.2Y0.8Ti3O 12 film and (110) diffraction peak of Bi0.85Eu0.15FeO3 annealed in oxygen is stronger than those annealed in an ambient atmosphere. The Bi0.85Eu0.15FeO3/Bi3.2Y0.8Ti3O12 bilayer thin films annealed in the oxygen atmosphere exhibit the maximum remanent polarization (2\mbi Pr) and remnant magnetization (2Mr) of 26 μ C/cm2 and 3.44 emu/g, respectively. The improved magnetic and ferroelectric properties can be attributed to the elimination of defects, such as oxygen vacancy and vacancy complexes.

Bi0.9Eu0.1FeO3 (BEFO) thin films were deposited on Pt(111)/Ti/SiO2/Si(100) substrates using the sol-gel method and rapid thermal annealing in an oxygen atmosphere. The effects of annealing temperature (400 ~ 700 C) on microstructure and multiferroic properties of thin films were investigated. The X-ray diffraction analysis showed that the BEFO thin films had an orthorhombic structure. The thin films showed ferroelectric and ferromagnetic properties with remanent polarization (2Pr) of 15 μC/cm2 and remnant magnetization (2Mr) of 4.2 emu/g. The leakage current density (J) of the BEFO thin film annealed at 700 °C was 4.25t10-8& A/cm2 at 150 kV/cm. The leakage current was affected not only by the microstructure but also by the interface between the Pt electrode and the BEFO thin films. Moreover, it was found that more than one conduction mechanism was involved in the electric field range used in these experiments. In the low electric field region, the leakage current was controlled by Poole-Frenkel emission. However, the mechanism could be explained by Schottky emission from the Pt electrode in the high electric field region.

Titanium oxide (TiO 2 ) thin films are prepared by the sol–gel method and annealed at 600 °C by conventional (CTA) and rapid thermal annealing (RTA) processes on fluorine-doped tin oxide -coated glass substrates for application as the work electrode for the dye-sensitized solar cells (DSSC). TiO 2 thin films are crystallized using a conventional furnace and the proposed RTA process at annealing rates of 5 °Cmin −1 and 600 °Cmin −1 , respectively. The TiO 2 thin films are characterized by X-ray diffraction, scanning electron microscopy and Brunauer–Emmett–Teller analysis. Based on the results, the TiO 2 films crystallized by RTA show better crystallization, higher porosity and larger surface area than those of CTA. The short-circuit photocurrent and open-circuit voltage values increased from 5.2 mAcm −2 and 0.6 V for the DSSC with the CTA-derived TiO 2 films to 8.3 mAcm −2 and 0.68 V, respectively, for the DSSC containing RTA-derived TiO 2 films.

Nanocrystalline ZnO thin films were prepared by the sol-gel method and annealed at 600 °C by conven- tional (CTA) and rapid thermal annealing (RTA) processes on fluorine-doped tin oxide (FTO)-coated glass substrates for application as the work electrode for a dye-sensitized solar cell (DSSC). ZnO films were crystallized using a con- ventional furnace and the proposed RTA process at anneal- ing rates of 5 °C/min and 600 °C/min, respectively. The ZnO thin films were characterized by X-ray diffraction (XRD) and atomic force microscopy (AFM) analyses. Based on the results, the ZnO thin films crystallized by the RTA process presented better crystallization than films crystallized in a conventional furnace. The ZnO films crystallized by RTA showed higher porosity and surface area than those prepared by CTA. The results show that the short-circuit photocur- rent (Jsc) and open-circuit voltage (Voc) values increased from 4.38 mA/cm 2 and 0.55 V for the DSSC with the CTA- derived ZnO films to 5.88 mA/cm 2 and 0.61 V, respectively, for the DSSC containing the RTA-derived ZnO films.

Bi3.2Gd0.8Ti3O12 (BGTO) thin films were deposited on Pt(111)/Ti/SiO2/Si(100) substrates using the sol-gel method and rapid thermal annealing in an oxygen atmosphere. The effects of annealing temperature (500–800°C) on microstructure and electrical properties of thin films were investigated. X-ray diffraction analysis shows that the BGT thin films have a bismuth-layered perovskite structure with preferred (117) orientation. The intensities of (117) peaks increases with increasing annealing temperature. The leakage current density (J) was 3.69×10−8 A/cm2 at 200 kV/cm. It was found that the leakage current was affected not only by the microstructure but also by the interface between the Pt electrode and BGTO thin films. In the low electric field region, the leakage current was controlled by Poole–Frenkel emission. In addition, the mechanism can be explained by Schottky emission from the Pt electrode in the high electric field region.

The preferred (002) orientation zinc oxide (ZnO) nanocrystalline thin films have been deposited on FTO-coated glass substrates by sol–gel spin-coating technology and rapid thermal annealing for use in dye-sensitized solar cells (DSSC). The effects of preannealing temperature (100 and 300°C) on the microstructure, morphology and optical properties of ZnO thin films were studied. The ZnO thin films were characterized by X-ray diffraction (XRD), scanning electron microscopic (SEM) and Brunauer–Emmett–Teller (BET) analysis. The photoelectric performance of DSSC was studied by I–V curve and the incident photon-to-current conversion efficiency (IPCE), respectively. From the results, the intensities of (002) peaks of ZnO thin films increases with increasing preannealing temperature from 100°C to 300°C. The increase in pore size and surface area of ZnO films crystallized at the increased preannealing temperature contributed to the improvement on the absorption of N3 dye onto the films, the short-circuit photocurrent (J sc) and open-circuit voltage (V oc) of DSSC. The higher efficiency (η) of 2.5% with J sc and V oc of 8.2 mA/cm2 and 0.64 V, respectively, was obtained by the ZnO film preannealed at 300°C.

Praseodymium-substituted bismuth titanate (Bi 3.2 Pr 0.8 Ti 3 O 12 , BPTO) thin films were successfully deposited on Pt(111)/Ti/SiO 2 /Si(100) substrates by spin coating with a sol-gel technology and rapid thermal annealing. The effects of annealing atmospheres (vacuum, ambient atmosphere and oxygen) on the growth and properties of thin films were investigated. The results show that the intensity of the (117) diffraction peak of Bi 3.2 Pr 0.8 Ti 3 O 12 film annealed in oxygen is stronger than those annealed in ambient atmosphere and vacuum. The XRD spectra demonstrated that a highly (117) orientation could be obtained when the Bi 3.2 Pr 0.8 Ti 3 O 12 thin film was annealed in an oxygen-sufficient environment. The BPTO thin films annealed in oxygen atmosphere exhibits the maximum remanent polarization (2P r ) of 49 μC/cm 2 and a low coercive field (2E c ) of 130 kV/cm, fatigue free characteristics up to ≥10 11 switching cycles. These results indicate that the BPTO thin film is useful in nonvolatile ferroelectric random access memory applications.

Nanocrystalline anatase TiO 2 thin films with different thicknesses (0.5-2.0 μm) have been deposited on ITO-coated glass substrates by a sol-gel method and rapid thermal annealing for application as the work electrode for dye-sensitized solar cells (DSSC). From the results, the increases in thickness of TiO 2 films can increase adsorption of the N3 dye through TiO 2 layers to improve the short-circuit photocurrent (J sc ) and open-circuit voltage (V oc ), respectively. However, the J sc and V oc of DSSC with a TiO 2 film thickness of 2.0 μm (8.5 mA/cm 2 and 0.61 V) are smaller than those of DSSC with a TiO 2 film thickness of 1.5 μm (9.2 mA/cm 2 and 0.62 V). It could be due to the fact that the increased thickness of Ti0 2 thin films also resulted in a decrease in the transmittance of TiO 2 thin films thus reducing the incident light intensity on the N3 dye. An optimum power conversion efficiency (η) of 2.9% was obtained in a DSSC with the TiO 2 film thickness of 1.5 μm.

ZnO-coated TiO2 (ZTO) thin films were deposited on ITO substrates by a sol–gel method for application as the work electrode for dye-sensitized solar cells (DSSCs). The I–V curve and the incident photon-to-current conversion efficiency (IPCE) value of DSSCs for ZTO thin films were studied and compared with single TiO2 films. The results show that the short-circuit photocurrent (J sc) and open-circuit voltage (V oc) values increased from 3.7 mA/cm2 and 0.68 V for the DSSCs with a single TiO2 film to 4.5 mA/cm2 and 0.72 V, respectively, for the DSSCs with a ZTO thin film. It indicated that the DSSCs with a ZTO thin film contributed to provide an inherent energy barrier that suppressed charge recombination significantly. In addition, the higher IPCE value in the ZTO thin film is attributed to the better charge separation by a fast electron transfer process using two semiconductors with different conduction band edges and energy positions.

High-performance pyroelectric infrared (IR) detectors have been fabricated using tantalate-doped lithium niobate LiNb 1 -x Ta x 0 3 (abbreviated as LNT, with x= 0-1.0) thin films deposited on Pt(1 1 11)/TilSiO 2 /Si(100) substrates by diol-based sol-gel processing, in which, tantalate (Ta) is adopted as dopant in lithium niobate. The randomly oriented LNT thin film exhibits a relatively small dielectric constant and a large pyroelectric coefficient. The pyroelectric characteristics of detectors with various tantalate contents, as a function of modulation frequency, were investigated. It was found that LiNb 0,8 Tau 0.2 O 3 had the largest voltage responsivity of 7020 (V/W) at 70 Hz, and a specific detectivity (D*) of 7.76 x 10 7 cm Hz 1/2 /W at 200 Hz. These results indicate that the LNT thin film with x=0.20 is most suitable for application as high-performance pyroelectric thin-film detectors.

Yttrium-substituted bismuth titanate (Bi 3.2 Y 0.8 Ti 3 O 12 , BYT) thin films were successfully deposited on Pt(1 1 1)/Ti/SiO 2 /Si(1 0 0) substrates by spin coating with a sol–gel technology and rapid thermal annealing. The effects of annealing temperature (500–800 °C) on microstructure and electrical properties of thin films were investigated. X-ray diffraction analysis shows that the BYT thin films have a bismuth-layered perovskite structure with preferred (1 1 7) orientation. The intensities of (1 1 7) peaks increases with increasing annealing temperature. With the increase of annealing temperature from 500 to 800 °C, the grain size of BYT thin films increases. The highly (1 1 7)-oriented BYT thin films exhibit a high-remnant polarization (2 P r ) of 58 μC/cm 2 and a low-coercive field (2 E c ) of 116 kV/cm, fatigue free characteristics up to >10 8 switching cycles. The leakage current density ( J ) were 4.38×10 −8 A/cm 2 at 200 kV/cm. These results indicate that the highly (1 1 7)-oriented BYT thin film is useful in nonvolatile ferroelectric random access memory applications.