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Natural water evaporation (NWE) is spontaneous and ubiquitous process that absorbs ambient thermal energy. Scavenging ambient thermal energy into electricity by NWE provides a promising approach to supply power for self-powered and low-cost devices and systems. Suitable materials and techniques are required to use this ubiquitous natural process for electricity generation. Herein, a continuous NWE-driven flexible generator is fabricated by painting Ni-Al layered double hydroxide (LDH) on a polyethylene terephthalate substrate at room temperature. The generator operates through an NWE-driven gradient of water that flows across the naturally formed surface-charged nanochannels between Ni-Al LDH flakes; i.e., the streaming potential mechanism. The output electrical characteristics of the device can be controlled by adjusting the environmental moisture and wind velocity. Continuous electricity output with a comparatively high power density of 16.1 μW cm−3 is achieved from a generator. The generator can maintain a stable output power under deformation. The output power of the generator can be scaled up to continuously power integrated circuit devices such as a digital calculator. Given the easy fabrication process of this flexible NWE-driven generator using an environmentally friendly LDH and its continuous electricity output with relatively high power density, this generator represents an important step towards practical green ambient energy harvesting.

A photo-detector with n-ZnO nano-arrays/p-NiO film structure was synthesized on flexible Ni foil substrate. In contrast to conventional detectors that detect only the photon energies greater than the band gap of working materials, the visible light with smaller photon energies (3.0 eV) than the band gap of both ZnO (3.3 eV) and NiO (3.7 eV) can be sensitively detected by this detector due to the spatially indirect type-II transition between ZnO nano-arrays and NiO film. The increase in output currents of the photo-detector with illumination density was observed at both forward and reverse bias, and it can be further enhanced by exerting external compressive strain along the c axis of ZnO nano-arrays by piezo-phototronic effect. A maximum enhancement of 1020% of the responsivity (R) was achieved under external compressive strain. The similar behaviors were demonstrated at four different excitation wavelengths (325, 365, 388 and 405 nm), providing compelling evidence that the responses performance of the photo-detector can be effectively enhanced using piezo-phototronic effect. Moreover, the piezo-phototronic effect enhanced performance can be well elucidated by the corresponding energy band diagram.

A series of Sr2MgSi2O7:Tb3+ nanophosphors is prepared using a high-temperature solid-state reaction. The x-ray diffraction patterns show that the crystal structure of the sample is not significantly affected by Tb3+ ions. However, the images of the scanning electron microscope illustrate that the average size of nanoparticles becomes larger with the increase of Tb3+ concentration. Unlike earlier investigations on down-conversion emission of Tb3+ ion excited by deep ultraviolet light, in this work, the photoluminescence characteristics of Sr2MgSi2O7 nanophosphors doped with different Tb3+ concentrations are analyzed under 374-nm excitations. The intense green emission at 545 nm is observed at an optimal doping concentration of 1.6 mol%. The main reason for the concentration quenching is due to the electric dipole–electric dipole interaction among Tb3+ ions.

A series of Zn2GeO4:Tb3+ nanophosphors have been prepared by the high temperature solid state method. The XRD patterns of samples are basically consistent with Zn2GeO4 standard card and the influence of Tb3+ ion on the peak shift is discussed detailedly. The SEM results show that the average sizes of all nanophosphors, whether undoped or doped, are about 50 nm except that some particles in Zn2GeO4 nanophosphor doped with 0.7 mol% terbium take on the cubic structure and the maximum size are about 130 nm. Under 265 nm excitation, there exists a broad blue emission belonging to Zn2GeO4 host. Moreover, the intense photoluminescence peaks at 490, 550 nm and weak peaks at 585, 622 nm of Tb3+ ions are obtained, and optimum Tb3+ doping concentration is 0.7 mol%. The decay curves of host emissions with the varied Tb3+ concentrations are measured, and the mechanisms of photoluminescence and energy transfer from Zn2GeO4 host to Tb3+ ions are analyzed systematically.

Summary Background and objectives Transcatheter arterial chemoembolization (TACE) is the first-line treatment for unresectable hepatocellular carcinoma (HCC). It consists of conventional TACE (cTACE) and drug-eluting beads TACE (DEB-TACE). The comparative outcomes of the two methods remain controversial. The study aim to research the optimal TACE strategy for unresectable HCC. Methods A systematic search of keywords, including ‘HCC’ and ‘drug-eluting beads’ was performed including four electronic databases: PubMed, Embase, China Biological Medicine Database (CBM), and Cochrane library databases from the date of inception to December 25, 2015. Review Manager 5.3 was used to calculate the pooled relative risks (RRs) and 95% confident intervals (CIs). Results Sixteen cohort studies (4 RCTs, 3 prospective cohorts, 9 retrospective cohorts) were included comprising a total of 1832 patients: 822 patients with DEB-TACE therapy and 1010 patients undergoing cTACE. The 1-, 2-, and 3-year overall survival (OS) rates and 1- and 2-year relapse-free survival (RFS) rates were significantly higher in DEB-TACE group, with pooled RRs of 1.12 (95% CI = 1.03–1.23, P = 0.007), 1.26 (95% CI = 1.03–1.54, P = 0.02), 1.69 (95% CI = 1.00–2.84, P = 0.04), 1.21 (95% CI = 1.01–1.44, P = 0.03) and 1.68 (95% CI = 1.17–2.43, P = 0.005). There was no statistical significance in 3-year RFS, tumor response and treatment-related adverse events. Conclusion Compared with cTACE, DEB-TACE therapy significantly improved 1-, 2-, and 3-year OS rates and the 1- and 2-year RFS rates.

The piezo-phototronic effect has drawn great interest recently due to its improvement of optoelectronic devices performance by effectively controlling the carrier generation, separation, transport, and/or recombination at the interface/junction of the p–n junction. In this study, a compact sensitivity controllable pressure sensor with the n -ZnO nano-arrays/ p -Cu 2 O film structure is synthesized on flexible Cu foil substrate, and the improved performance due to piezo-phototronic effect is characterized systematically. The heterostructure shows a nearly ideal rectifying behavior with substantial forward current of more than 1 mA (at 3 V) under pressure free and dark conditions, indicating excellent p - n junction was formed at the n -ZnO nano-arrays/ p -Cu 2 O film interface. The linear dependence of switch ratio ( SR ) ( I/I 0 ) on the applied pressure and response time of ~1 s were observed in the pressure sensor. The linear dependence can be further improved and a value up to 376% is reached by the illumination radiation of the 405 nm violet light emitting diodes (LEDs), which had been tactfully embedded within the device. The advantages of embedding LEDs in the sensor lie in reducing of device volume as well as preventing influence of environment light on the sensor performance. Furthermore, a substantial enhancement in the sensitivity ( I-I 0 /I 0 / ∆ P ) of the pressure sensor is achieved by adjusting the illumination intensity, which reaches 918% at the illumination intensity of 11.7 mW/cm 2 . The piezo-phototronic effect enhanced performance can be well elucidated by the corresponding energy band diagram. Our achievement provides a very promising method to improve the SR and sensitivity controllability of pressure sensor using piezo-phototronic effect.

Existing DAG-based task models in real-time scheduling research assume well-nested structures recursively composed by single-source-single-sink parallel and conditional components. However, realistic OpenMP task systems in general have more flexible structures that do not comply with this assumption. In this paper, we model the behaviors of general OpenMP task systems with non-well-nested branching structures and study the problem of how to bound their worst-case response times (WCRT). A naive solution is to apply the established WCRT bound for DAG tasks without conditional branches to the exponentially many possible execution flows, which has exponential time complexity. In this paper, we develop a linear-time algorithm to efficiently calculate WCRT bounds for OpenMP task systems with non-well-nested branching structures. Experiments with both synthetic task graphs and realistic OpenMP programs are conducted to evaluate the performance of our method.

Some typical dual-ring erbium-doped fiber lasers with hyperchaos behaviors are taken as nodes to construct two kinds of small-world networks—NW and WS networks. Based on Lyapunov stability theorem, the appropriate controllers are designed and the outer synchronization between the small-world networks with diverse structures and different node numbers is further investigated. The simulation results show that the perfect synchronization between the complex small-world networks is realized, which is of potential application for all optical communication network.

We have prepared a flexible natural water evaporation (NWE) driven silicon carbide (SiC) nano-generator on the polyethylene terephthalate (PET) substrate. When the water driven by evaporation flows through the surface of SiC material, the solid-liquid interaction between water and SiC will induce continuous electricity output. The detail mechanism of the solid-liquid interaction is discussed in this paper. The open circuit voltage (Voc) and short circuit current (Isc) are nearly proportional to the evaporation height and evaporation width of the generator, respectively. Moreover, the Voc and Isc of the generator can be finely controlled by regulating the relative humidity, air flow and photo-thermal energy assistant technique.

Natural water evaporation (NWE) can be used as a driving force to generate electricity. NWE-driven generators (NWEGs) require materials with charged surfaces. However, the quantitative adjustment of the surface charge density (dc) remains difficult and the relationship between dc and NWEG performance has not been clarified. Herein, Ni–Al layered double hydroxide (LDH) films with tailored structural dc in the range of 2.52–4.59 e/nm2 were synthesized by precisely adjusting the molar ratio of Al3+ to Ni2+. The Ni–Al LDH films were assembled into NWEGs by the spraying method and then their electrical performance was investigated. Strong positive correlations were observed between dc, open-circuit voltage (Voc), and short-circuit current (Isc); that is, the larger dc, the higher Voc and Isc. The maximum Voc of ~0.6 V, Isc of ~0.3 μA, and output power density of ~15 μW/cm3 were achieved simultaneously for a 4 × 1.5 cm NWEG with a maximum dc of 4.59 e/nm2. A reasonable increase of dc resulted in improved device performance, which was attributed to the positive correlation between the densities of both hydroxide ions in the diffusion layer and positive charge on the Ni–Al LDH film surface. In addition, a relatively stable total Voc of ~2.5 V and Isc of ~1.5 μA were obtained using eight NWEGs with a modified individual generator structure. The eight assembled NWEGs successfully powered a simple electronic watch. The spraying method used to fabricate the NWEGs not only greatly shortened the device molding time, but also markedly improved device stability. This study reveals a new avenue to guide the design of materials and to improve the performance of flexible self-powered NWEGs.

The CaSrSiO4 nanophosphor-doped 0.7 mol% Tb3+ ions have been prepared by the high-temperature sintering method. XRD pattern is consistent with the standard card of CaSrSiO4 host, and the average particle size of CaSrSiO4:0.7Tb is about 50 nm. There exist intense green (544, 552 nm) and weak blue (485, 488 nm), yellow (588 nm), and red (625 nm) emissions under the excitation of 325 nm He–Cd laser, corresponding, respectively, to the transitions of Tb3+ ions from 5D4 and its splitting to 7F5,4,6,3,2 energy levels. The low-temperature photoluminescence characteristics of the sample are measured in the range of 290–10 K. The relationship between fluorescence intensity ratio and temperature is FIR = 0.895 + 0.469exp(− 145.8/T) and the maximum value of sensitivity is 17.6 × 10− 4 K− 1 at 70 K, indicating that CaSrSiO4:Tb3+ nanophosphor is a promising sensing material for low-temperature measurement.

Trichosanthes pericarpium (TP) had been widely used to cure patients of cardiovascular disease for 2,000 years in China. This study aims to extend our previous work to explore the mechanism underlying the protective effect of TP on acute myocardial ischemia (AMI). We hypothesized that TP may display its protective effect on AMI by promoting the mobilization of endothelial progenitor cells (EPC) via up-regulating the expression level of vascular endothelial growth factor (VEGF), endothelial nitric oxide syntheses (eNOS), nitric oxide (NO), and matrix metalloproteinase 9 (MMP-9) in AMI rats. To confirm this hypothesis, we treated AMI model rats with intragastrical administration of TP aqueous extract (TPAE), and examined both changes in the number of CEPC, and the expression levels of VEGF, eNOS, NO, and MMP-9 in myocardial tissue and their plasma content in these rats. Rats in each group were randomly divided into seven subgroups. From day 1 to 7 following AMI modeling, rats in these subgroups was sequentially phlebotomized from their celiac artery after being anesthetized by chloral hydrate. We found that, compared with the AMI model rats, in rats treated by TPAE, the CEPC counts, the expression of VEGF, eNOS, NO, and MMP-9 in myocardial tissue and their plasma content all increased more rapidly 7 days after AMI and remained at higher level (P < 0.05 or P < 0.01). Our results showed that, in AMI rats, the TPAE could significantly promote the mobilization of EPC and up-regulate the expression level of VEGF, eNOS, NO, and MMP-9 in myocardium and their plasma content. Therefore, our results suggest that TAPE may regulate EPC mobilization through up-regulating the expression level of VEGF, eNOS, NO and MMP-9 in the myocardium of AMI rats.

Dy3+-doped and Dy3+:Yb3+-codoped oxyfluoride glass ceramics have been prepared by high-temperature solid phase sintering method. The micrographs of scanning electron microscope show that a lot of nanorods are formed on the surface of Dy3+:Yb3+-codoped sample. The excitation spectra and emission spectra are measured, respectively, and intense photoluminescence peaks at 482 and 575 nm corresponding to the transitions of Dy3+ ions are found in single-doped samples under 388-nm excitation. For Dy3+:Yb3+-codoped oxyfluoride glass ceramics, the intensities at blue and green bands become weaker whereas the intensity at 695 nm gets stronger. The indirect sensitization is detailedly discussed and Commission Internationale de l′E-clairage chromaticity coordinates exhibit that two kinds of oxyfluoride glass ceramics are available candidates for the solid-state white light emission.

In this work, we present timed automata as a natural tool for posing and solving time varying postman problems. We show that these problems can be reduced to the problem of finding the shortest runs in our Timed Automata System TAS model. The problem can then be solved by incorporating the reachability analysis RA algorithm into a binary search framework. However, the scale of the TAS model is too large to adapt the RA algorithm embedded in the UppAal. Thus, we propose a composition strategy to transform the current TAS model into a Generalized Timed Automaton GTA model, such that the number of timed automata in our model decreases from to . Computational results show that the GTA model can solve small-sized instances optimally and that it can obtain a better optimality gap than those obtained by the cutting plane algorithm.

Herein we report a one-step approach to the highly efficient synthesis of graphene oxide/Mn3O4 (GO/Mn3O4) hybrids with superior catalytic activities for decomposition of methylene blue (MB) in water. This method exploits the pristine graphene oxide/manganese sulfate (GO/MnSO4) suspension produced by the modified Hummers method as the raw materials, in which GO/MnSO4 has been in situ converted into GO/Mn3O4 hybrid in combination with KOH and air. This atom-economic reaction produces only K2SO4 crystal as the by-product which meets the standard of green chemistry. For catalystic degradation of MB dye at room temperature, the as-prepared GO/Mn3O4 catalysts result in a significant enhancement in the reaction rate compared to that of the bare Mn3O4 particles with the assistance of H2O2. Typically, 50 mL of MB (50 mg L−1) can be 100% decolorized and 77% mineralized with 10 mg of the GO/Mn3O4 hybrid. Such excellent catalytic performance of the GO/Mn3O4 hybrid is mainly attributed to the synergistic effects of GO, Mn3O4, H2O2 and MB molecules. Based on the hydroxyl radical experiments, the catalytic activity of GO/Mn3O4 hybrids for degradation of MB is closely related with the amount of the reactive •OH species generated from H2O2.

ZnO thin films were deposited on graphite substrates by ultrasonic spray pyrolysis method with Zn(CH3COO)2·2H2O aqueous solution as precursor. The crystalline structure, morphology, and optical properties of the as-grown ZnO films were investigated systematically as a function of deposition temperature and growth time. Near-band edge ultraviolet (UV) emission was observed in room temperature photoluminescence spectra for the optimized samples, yet the usually observed defect related deep level emissions were nearly undetectable, indicating that high optical quality ZnO thin films could be achieved via this ultrasonic spray pyrolysis method. Considering the features of transferable and low thermal resistance of the graphite substrates, the achievement will be of special interest for the development of high-power semiconductor devices with sufficient power durability.

Vanadium oxide (VOx) thin films with and without in situ AlN layer were grown on single crystal sapphire substrates by pulsed laser deposition (PLD) with V2O5 target. The significant structure and morphology transforms resulted from the insertion of in-situ AlN layer were observed by X-ray diffraction (XRD) and field-emission scanning electron microscope (FESEM). To interpret the mechanism behind these phenomena, the valence state variation of vanadium (V) in VOx films induced by in-situ AlN layer was investigated by X-ray photoelectron spectroscopy (XPS) analyses. The results indicated that the valence state of V become more complicated and VOx films with the mixed V valence state of V5+,V4+and V3+ were obtained due to the introduction of AlN interfacial stress layer. Our achievements will be helpful for understanding the physical mechanism behind the exotic characteristics of VOx films induced by stress layer.

The heterojunction diodes with n-ZnO/ZnMgO/p-GaN structure have been deposited on the commercially available p-GaN/sapphire substrates by a simple process of ultrasonic spray pyrolysis. To demonstrate the effect of ZnMgO layer as electron blocking layer, the carrier transport mechanisms of both n-ZnO/p-GaN and n-ZnO/ZnMgO/p-GaN heterojunctions were systemically investigated by temperature-dependent current–voltage measurements. The results revealed that the multistep tunneling is the dominant carrier transport mechanism in n-ZnO/ZnMgO/p-GaN heterojunctions under forward current, accurately controlled ZnMgO layer thickness can effectively block electron injection from ZnO to GaN and promote hole injection from GaN to ZnO. Therefore, the design and application of ZnO based heterostructure devices will benefit significantly from these achievements.

ZnO nanostructures are grown on Si and GaAs substrates by chemical bath deposition (CBD) method. Scanning electron microscope (SEM) measurements indicate that ZnO nanorods are formed on Si substrate, in contrast to the nanorods, network ZnO nanowalls are obtained on GaAs substrate. To elucidate the mechanism of ZnO nanostructures grown by CBD method, the morphology evolution mechanisms of the ZnO with growth time and solution concentration nanostructures are investigated systematically. A corresponding growth model from the view of crystal nucleation and growth process is proposed. The understanding of morphology evolution of ZnO nanostructures on different substrates will facilitate the controllable growth of ZnO nanostructures and therefore crucial for the application of ZnO nanodevices.

We report on the effect of seed layers thickness on the synthesis of one dimensional (1D) ZnO rods using chemical bath deposition method. This procedure allows us to control the length and diameter of 1D ZnO rods in a large size range by modifying the ZnO seed layer thickness. With the increase in thickness of the seed layer, the length of the 1D ZnO rods ranges from 13.1 μm to 2.1 μm, and the diameter varies from 2.4 μm to 102 nm, meanwhile the laying 1D ZnO rods standup gradually. Photoluminescence measurements indicate that the near band edge emission of the 1D ZnO rods blueshift to higher energy direction with the increasing seed layers thickness.

In this work, n-type ZnO nanorods (NRs) were fabricated on a p-type Si substrate to form a ZnO NRs/Si structure using a low-temperature wet chemical bath deposition method. Kelvin-probe-based surface photovoltage (KP-based SPV) technology was used to study the behavior of surface photogenerated charges for the as-grown heterostructure. In general, the KP-based SPV response range of the ZnO NRs/Si structure was significantly expanded compared with the bare Si substrate, due to the incorporation of ZnO NRs. Moreover, the SPV response amplitude for ZnO NRs/Si structure also depended on the length and diameter of the NRs, and the corresponding mechanism was elucidated in terms of O2 adsorption. The photovoltaic application of the ZnO NRs/Si based structure would benefit significantly from these achievements.

ZnO nanorods (NRs) were grown perpendicularly on graphite substrates using low-temperature wet chemical bath deposition (CBD) with sputtered ZnO film as seed layer. The individual ZnO NRs exhibit single-crystalline feature with well defined hexagonal prism shape and smooth side facets. The high optical qualities of ZnO NRs on graphite substrates were demonstrated by the dominant near-band edge emission and nearly undetectable deep level emissions in room-temperature photoluminescence spectra. The extremely low average reflectance of 0.45 % was obtained for the ZnO NRs/graphite structure in the spectra range from 200 to 1100 nm, indicating that the reported ZnO NRs/graphite structures have significant opportunity for potential application in high-performance photovoltaic devices. Considering the excellent material characteristics of ZnO NRs and the versatile and fascinating features of graphite substrates, the achievements make it possible for the development of high-performance ZnO-based nano-devices even in transferable, flexible, or stretchable forms.

N-doped ZnO (ZnO:N) films are grown by a low-pressure plasma assisted metal-organic chemical vapor deposition system on insulating Si (111) substrate. N 2 O plasma is used as the N precursor of ZnO:N films, which is activated by a radio frequency generator. The influence of activating power on the properties of ZnO films is studied by means of X-ray diffraction, Hall effect, X-ray photoelectron spectroscopy and low temperature photoluminescence measurements. P -type ZnO:N films with acceptable electrical and optical properties are achieved under the optimal activating power conditions. XPS study reveals a competition between acceptor N O and donor (N 2 ) O during doping influence the properties of ZnO films.

ZnO thin films were deposited on graphite substrates by ultrasonic spray pyrolysis method. The effects of substrate temperature and film thickness on the crystalline structure, morphology, and optical properties of the as-grown ZnO films were investigated systemically. Results illustrated that dense ZnO films with hexagonal wurtzite structure were uniformly distributed on the substrate. Strong near-band edge ultraviolet (UV) emission peaks were observed in room temperature photoluminescence (PL) spectra for the samples prepared under optimized parameters, yet the usually observed defect related deep level emissions were nearly undetectable, indicating high optical quality ZnO films could be achieved via this easy process under optimal conditions. The successful growth of polycrystalline ZnO films on graphite offers the significant opportunity to be readily transferred onto any rigid or flexible foreign substrates, since the graphite substrates consist of weakly bonded layer structure.

The parameter identifiers and synchronization controllers are designed based on stability theory in order to realize the synchronization of two chaotic systems with diverse structures and the parameter identification of the uncertain system. The stimulated Raman scattering and NH 3 laser are taken as examples. The simulation results show that the global synchronization between the uncertain stimulated Raman scattering and the NH 3 laser can be achieved, and all the parameters in the stimulated Raman scattering system can be identified simultaneously. The method is proved effective and feasible.

The inorganic-organic hybrid junction was synthesized on ITO glass substrate, which was consisted of an n-type ZnO nanorods (NRs) grown by low-temperature aqueous chemical growth method and a p-type polyfluorene (PF) organic film fabricated by spin-coating. The experimental results indicate that densely and uniformly distributed ZnO nanorods are successfully grown on the PF layer. The thickness of the PF layer plays a dominant role for the current-voltage (I–V) characteristic of the ZnO NRs/PF inorganic-organic hybrid junction device, and a p-n junction with obviously rectifying behavior is achieved with optimal PF layer thickness. The photoluminescence (PL) spectrum covering the broad visible range was obtained from the n-ZnO nanorods/p-polyfluorene (PF) structure, which was originated from the combination of the PF-related blue emission and the ZnO-related deep level emission.

ZnO nanowires homojunction LED with phosphorus-doped p-ZnO nanowires/n-ZnO nanowires structure was fabricated on Si substrate by simple chemical vapor deposition. The scanning electron microscope show well-aligned undoped ZnO nanowires and phosphorus doped ZnO nanowires with uniform diameter, length, and density were grown perpendicularly on Si substrate. The phosphorus related acceptor emissions were observed from photoluminescence spectra of phosphorus-doped ZnO nanowires at 20 K. Moreover, the current–voltage measurement of ZnO nanowires homojunction LED showed a good rectifying behavior with a turn-on voltage was about 3.8 V and a reverse breakdown voltage was about 6 V. Distinct electroluminescence with ultraviolet and visible emissions was detected from this device at room temperature.

A p-ZnO:N/n-GaN:Si structure heterojunction light-emitting diode (LED) is fabricated on c-plane sapphire by full metal organic chemical vapor deposition (MOCVD) technique. The p-type layer with hole concentration of 8.94 x 10(16) cm(-3) is composed of nitrogen-doped ZnO using NH(3) as the doping source with subsequent annealing in N(2)O plasma ambient. Silicon-doped GaN film with electron concentration of 1.15 x 10(18) cm(-3) is used as the n-type layer. Desirable rectifying behavior is observed from the current-voltage (I-V) curve of the device. The forward turn on voltage is about 4 V and the reverse breakdown voltage is more than 7 V. A distinct ultraviolet (UV) electroluminescence (EL) with a dominant emission peak centered at 390 nm is detected at room temperature from the heterojunction structure under forward bias conditions. The origins of the EL emissions are discussed in comparison with the photoluminescence (PL) spectra. (C) 2010 Elsevier B.V. All rights reserved.

Influence of annealing temperature on the properties of Sb-doped ZnO thin films were studied. Hall measurement results indicated that the Sb-doped ZnO annealed at 950 °C was p-type conductivity. X-ray diffraction (XRD) results indicated that the Sb-doped ZnO thin films prepared at the experiments are high c-axis oriented. It was worth noting that p-type sample had the worst crystallinity. The measurements of low-temperature photoluminescence (PL) spectra indicate that the sample annealed at the temperatures of 950 °C showed strong acceptor-bound exciton (A0X) emission, and confirmed that it is related to Sb-doping by comparing with the undoped ZnO low-temperature PL spectrum.

Sb-doped zinc oxide (ZnO) films grown by metal organic chemical vapor deposition (MOCVD) were investigated. The influence of Sb-doping concentration on the optical and structural properties of ZnO was investigated. The deep-level emission was suppressed gradually by Sb doping. The grain size of ZnO was also increased by Sb doping. The reasons for improvement in optical and structural properties of ZnO thin films are also discussed.

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.

ZnO nanowires with different arsenic concentration were grown on Si (1 0 0) substrates by chemical vapor deposition method without using catalyst. Zn/GaAs mixed powders were used as Zn and As source, respectively. Oxygen was used as oxidant. The images of scanning electron microscope show that the arsenic-doped ZnO nanowires with preferred c -axial orientation were obtained, which is in well accordance with the X-ray diffraction analysis. The arsenic related acceptor emission was observed in the photoluminescence spectra at 11 K for all arsenic-doped ZnO samples. This method for the preparation of arsenic-doped ZnO nanowires may open the way to realize the ZnO nanowires based light-emitting diode and laser diode.

CdS x Se1−x quantum dots were fabricated by a simple spin-coating heat volatilization method on InP wafer. Temperature dependent photoluminescence of CdS x Se1−x quantum dots was carried out in a range of 10–300 K. The integrated photoluminescence intensity revealed an anomalous behavior with increasing temperature in the range of 180–200 K. The band gap energy showed a redshift of 61.34 meV when the temperature increased from 10 to 300 K. The component ratio of S to Se in the CdS x Se1−x quantum dots was valued by both the X-ray diffraction data and photoluminescence peak energy at room temperature according to Vegard Law. Moreover, the parameters of the Varshni relation for CdS0.9Se0.1 materials were also obtained using photoluminescence peak energy as a function of temperature and the best-fit curve: α = (3.5 ± 0.1)10−4 eV/K, and β = 210 ± 10 K (close to the Debye temperature θ D of the material).

Ultralong ZnO piezoelectric-fine-wires (PFWs) with a perfect hexagonal structure have been prepared by an upstream growing chemical vapor deposition (CVD) method. Furthermore, isolatable and flexible piezoelectric strain sensors based on individual ZnO PFWs have been fabricated by a simple and reliable technique. The whole device was fully packaged by epoxy polymeric resin (EPR). The I-V characteristic of the isolatable sensor is highly sensitive to the strain applied on it, which was well interpreted in terms of variation in Schottky barrier height (SBH) caused by strain induced band structure change and piezoelectric effect. The sensor exhibited excellent stability and fine reversibility, and a remarkably high gauge factor up to 1010 had been achieved. It is expected that the isolatable and flexible piezoelectric strain sensor demonstrated here will have applications in detection of external mechanical forces, as well as electromechanical switch with a high ON/OFF ratio.

Well-aligned ZnO nanorod arrays were synthesized by low-temperature wet chemical bath deposition (CBD) method on Si substrate under different conditions. Results illustrated that dense ZnO nanorods with hexagonal wurtzite structure were vertically well-aligned and uniformly distributed on the substrate. The effects of precursor concentration, growth temperature and time on nanorods morphology were investigated systematically. The mechanism for the effect of preparation parameters was elucidated based on the chemical process of CBD and basic nucleation theory. It is demonstrated that the controllable growth of well-aligned ZnO nanorods can be realized by readily adjusting the preparation parameters. Strong near-band edge ultraviolet (UV) emission were observed in room temperature photoluminescence (PL) spectra for the samples prepared under optimized parameters, yet the usually observed defect related deep level emissions were nearly undetectable, indicating high optical quality ZnO nanorod arrays could be achieved via this easy process chemical approach at low temperature.

In this paper, ZnO films are deposited on freestanding thick diamond films (FTDF) by plasma-assisted metal organic chemical vapour deposition (MOCVD). Diethyl zinc (DEZn), O2 and N2O are applied as precursors and different substrate temperatures are used to achieve high quality ZnO films. The influence of substrate temperature on the properties of ZnO films is systematically investigated by X-ray diffraction (XRD), Hall measurements and electron probe microanalysis (EPMA). Experimental results demonstrate that ZnO films deposited at 600°C and 73 Pa display a fine electrical quality and Zn/O atomic ratio plays an important role in the electrical property of ZnO films.

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 As Zn –2V Zn 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.