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The hollow polymer microchannels with different shapes and dimensions have been fabricated by the MIMIC method and the heating process for the first time. The smallest cross-sectional dimensions of hollow polymer microchannels were about 2.6 μm in the vertical direction and 3.5 μm in the horizontal direction. The length of hollow polymer microchannels increased parabolically with the heating temperature in the range of 30–135 °C. And the influence of the PDMS mold cross-sectional areas on the length of the microchannels was invetigated. Furthermore, the forming mechanism of hollow polymer microchannels was disscussed in detail. This technique provides a cheap, simple and controllable way for the preparation of microchannels.

Heterojunction light-emitting diodes (LED) based on n-ZnO/CsPbBr3/p-GaN have been fabricated by using pulsed laser deposition (PLD). The effects of the CsPbBr3 interlayer on the electroluminescence (EL) performance of n-ZnO/p-GaN have been systematically studied. It was found that the CsPbBr3 interlayer plays an important role in the emission performance of the heterojunction LED. By adjusting the thickness of CsPbBr3, the emission peaks of the heterojunction LED change from violet to greenish-yellow, indicating that the electroluminescence characters can be tuned by the CsPbBr3 film thickness. Detailed emission mechanisms influenced by the CsPbBr3 film have been investigated using the Anderson band diagram. The results provide a new method for the fabrication of single-chip white LEDs.

With vacuum thermal evaporation, the CuI film was deposited on quartz and n-GaN substrates, and the morphology, crystalline structure and optical properties of the CuI films were investigated. According to the XRD results, the CuI film preferentially grew along [111] crystal orientation on the GaN epilayer. With Au and Ni/Au ohmic contact electrodes fabricated on CuI and n-GaN, a prototype p-CuI/n-GaN heterojunction UV photodetector strong UV spectral selectivity was created. At 0 V and 360 nm front illumination (0.32 mW/cm2), the heterojunction photodetector displayed outstanding self-powered detection performance with the responsivity (R), specific detectivity (D*), and on/off ratio up to 75.5 mA/W, 1.27×1012 Jones, and ∼2320, respectively. Meanwhile, the p-CuI/n-GaN heterojunction photodetector had excellent atmosphere stability.

Due to the ultra-wideband gap, high transmittance in the ultraviolet (UV) region, and excellent environmental stability, zinc gallium oxide (ZnGa2O4) has attracted considerable interest in deep-ultraviolet photodetectors. Here, ZnGa2O4 thin film was fabricated on different substrates by pulsed laser deposition with a post-annealing process under an oxygen atmosphere. It is found that the substrates have a great impact on the morphology, structure, and crystal quality of thin film. After annealing, the thin film quality has been improved. The metal–semiconductor–metal photodetector shows excellent reproducible characteristics and fast response performance, which demonstrates great potential in next-generation optoelectronic devices.

All-inorganic lead-free perovskite

High-quality CsPbBr3 thin films have been fabricated by pulse laser deposition (PLD) technique and severed as an interlayer for n-ZnO/p-GaN heterojunction ultraviolet (UV) photodetector. The self-powered photodetectors based on n-ZnO/CsPbBr3/p-GaN heterojunction exhibited a high peak responsivity of 44.53 mA/W and detectivity of 2.03✕1012 cm·Hz1/2W−1 under zero bias voltage, which has increased ∼30 and ∼178 times than that of the n-ZnO/p-GaN device, respectively. Meanwhile, the photodetector with excellent stable and reproducible characteristics were also demonstrated and the photoresponse time has been drastically shortened by inserting the CsPbBr3 interlayer. The key role of the CsPbBr3 interlayer, as a carrier transport layer, has been demonstrated by the energy-band diagram. The enhanced performances of n-ZnO/p-GaN heterojunction make them promising application in self-powered photodetectors.

Light emitting diodes (LEDs) based on n-SnO2/p-GaN heterojunction were fabricated by pulsed laser deposition (PLD). The effects of post-annealing treatment and interfacial layers on electroluminescence (EL) of n-SnO2/p-GaN were investigated. After annealing in vacuum, all the LED devices with different interfacial layers exhibit a nonlinear current-voltage behavior. The SnO2/p-GaN light emitting diodes exhibit two emission peaks, a violet peak (410 nm) and the broad yellow-orange emission band (600–700 nm), whereas only the yellow-orange EL spectra could be found in the SnO2/AlN/p-GaN. Using the band diagram, the carrier blocking process by different interfacial layer and the electroluminescence mechanisms of heterojunction LEDs were discussed in detail.

CuI film was grown by thermal evaporation technology on TiO2 nanorods array synthesized using a hydrothermal method, and a p-CuI/n-TiO2 heterostructure photodetector was constructed. The structure, morphology, light absorption, and photoresponse performance of the device were investigated. The heterojunction detector is self-powered and sensitive to light in the range of 320nm∼450nm. At 0V, the on/off ratio of the device is ∼770. The peak responsivity (0V, 410nm) is about 4.5mA/W and the peak detectivity is 1.08×1011 Jones. Also, the reproducibility and stability of the heterojunction photodetector are excellent. This work provides an effective route for the study of self-powered photodetectors.

We report a sandwich-structured surface-enhanced Raman scattering substrate by integrating gold nanoparticles and electron beam lithography-fabricated hexagon-shaped silver nanohole arrays separated by single layer graphene. In the sandwich configuration, the graphene interlayer plays multiple roles for promoting the surface-enhanced Raman scattering performances: (i) acting as a supporting layer to avoid the dropping of the top layer of gold nanoparticles; (ii) an intrinsic spacer to create nanometer-scale gaps between gold nanoparticles and hexagon-shaped silver nanohole arrays; (iii) serving as a protective layer to suppress the oxidation of the bottom metal silver; (iv) functioning as a molecule harvester for adsorbing the target analyte. By decreasing inter-hole distances of hexagon-shaped silver nanohole arrays, we have obtained sub-10 nm-wide gaps neighboring the adjacent silver holes. Finite element numerical simulations demonstrated that the gold nanoparticle-graphene-hexagon-shaped silver nanohole array hybrid system generates a substantial amount of hot spots with strong electric field enhancement. The well-designed and fabricated gold nanoparticle-monolayer graphene-hexagon-shaped silver nanohole array sandwich structure exhibits high sensitivity with the limit of detection at sub-picomolar level and good reproducibility with a standard deviation of 6.2% for crystal violet. The work endows great potentials to the rational design and fabrication of two-dimensional material-plasmonic hybrids for surface-enhanced Raman scattering applications.

A new frustrated triangular lattice antiferromagnet Na2BaNi(PO4)2 was synthesized by high temperature flux method. The two-dimensional triangular lattice is formed by the Ni2+ ions with S = 1. Its magnetism is highly anisotropic with the Weiss constants θ CW = –6.615 K (H ⊥ c) and –43.979 K (H ∥ c). However, no magnetic ordering is present down to 0.3 K, reflecting strong geometric spin frustration. Our heat capacity measurements show substantial residual magnetic entropy existing below 0.3 K at zero field, implying the presence of low energy spin excitations. These results indicate that Na2BaNi(PO4)2 is a potential spin liquid candidate with spin-1.

The replicas with resolution doubling have been fabricated by capillary force lithography. We studied several masters with characteristic sizes range from micron to submicron. Replicas with resolution doubling fabricated by a DVD master were demonstrated and discussed in detail. The fabricated replicas demonstrated an average period of ~370 nm, which is half period of the DVD master. This method breaks the rule of one-to-one replication. The key factor to fabricate a replica with resolution doubling is to utilize a thin film with the thickness between 50 nm and 100 nm for the DVD master. Therefore, it seems to be no threshold for anyone to apply this method. Meanwhile it exhibits excellent reproducibility and stability.

All-inorganic perovskite CsPbBr

CsPbI3 thin films with orthorhombic phase were prepared on Si (100) substrates by the pulse laser deposition (PLD). The photoelectric characteristics of the CsPbI3 films had been investigated. The photodetector based on CsPbI3/n-Si heterojunction was sensitive to red wavelengths, showing the peak responsivity of 51.9 mA/W (695 nm). The excellent photoelectric characteristics of the CsPbI3 films grown by PLD are clearly demonstrated and should be widely applicable to optoelectronic devices.

ZnS/Au/ZnS tri-layer films were deposited on quartz glass substrates by pulsed laser deposition. The influence of Au layer thickness on optical and electrical properties of the tri-layer ZnS/Au/ZnS was studied. X-ray diffractometer (XRD) and scanning electron microscope were employed to characterize the crystalline structure and surface morphology of the tri-layer films. Hall measurements, ultraviolet and visible spectrophotometer, four-point probe were used to explore the optoelectronic properties of the ZnS/Au/ZnS. The increase of Au layer thickness resulted in the decreased resistivity, the increased carrier concentration, and the declined transmittance in the visible light region.

The p-CuI/n-ZnO heterojunction photodetectors have been fabricated by thermal evaporation technique and pulsed laser deposition with a tubular furnace. The morphology, structure, and the light response performances of the device were investigated. The p-CuI/n-ZnO heterojunction photodetectors demonstrated a high on/off ratio of 5500, high peak responsivity of 0.235 A/W, and high specific detectivity of 1.23 × 10 12 c m H z 1 / 2 / W at − 5 V bias voltage under 385 nm light illumination. Furthermore, the p-CuI/n-ZnO heterojunction photodetectors exhibited excellent reproducibility and stability.

T. koningii, T. harzianum, T. asperellum, T. longibrachiatum, and T. viride were analyzed using liquid chromatography-tandem mass spectrometry to determine whether melatonin is present. Results showed that there were abundant amounts of endogenous melatonin in five Trichoderma species, but no melatonin was found in any of the culture filtrates. T. asperellum had the highest amount of melatonin (27.588 ± 0.326 μg g(-1) dry mass), followed by T. koningii, T. harzianum, T. longibrachiatum, and T. viride. The endogenous melatonin content of T. asperellum in controlled-stress growth conditions was also detected. The data showed that chemical stressors (CdCl2 , CuSO4 , and H2 O2 ) provoked an increase in endogenous melatonin levels. CdCl2 had the highest stimulatory effect on melatonin production, as the product reached reaching up to three times the melatonin content of the control. NaCl stimulated a decrease of melatonin. Acidic conditions (pH 3 and pH 5) as well as slightly alkaline conditions (pH 9) resulted in an increase in the melatonin content, whereas pH11 resulted in a significant decrease in the melatonin content, only 12.276 ± 0.205 μg g(-1) dry mass. The current study is first to report melatonin content and the change of melatonin content under different stress situations in Trichoderma spp.

We demonstrate an efficient ultraviolet (UV) photodetector operating at room temperature based on n-ZnO nanorods/i-ZnO/p-GaN heterojunctions. We employ x-ray diffraction and field-emission scanning electron microscopy to confirm the high quality of the ZnO nanorods using an undoped ZnO film as the interlayer. Then, we investigate the photoelectric properties of the fabricated photodetector with UV light illumination under a different reverse bias. Based on the current-voltage curve, the photocurrent to dark current ratio is approximately 73.3 at −4 V. At zerobias voltage, the peak responsivity was 138.9 mA/W at 362 nm under front-illumination conditions. Time-varying measurements indicate the reproducibility and stability of the heterojunction photodetector.

The n-ZnO:Ga/p-GaN:Mg and n-ZnO:Ga/i-ZnO/p-GaN:Mg heterojunction light emitting diodes (LEDs) were fabricated by the pulsed laser deposition (PLD) technique. The blue electroluminescence (EL) of the n-ZnO:Ga/p-GaN:Mg heterojunction LEDs is emitted mainly from the p-GaN layer instead of the n-ZnO:Ga layer, for the reason that the electron injection from n-ZnO:Ga prevailed over the hole injection from p-GaN:Mg due to the higher carrier concentration and carrier mobility in n-ZnO:Ga. On the other hand, the n-ZnO:Ga/i-ZnO/p-GaN:Mg heterojunction LEDs exhibited dominant ultraviolet-blue emission. The reason for this difference is attributed to the inserted undoped i-ZnO layer between n-ZnO:Ga and p-GaN:Mg, in which the holes from p-GaN:Mg and the electrons from n-ZnO:Ga are recombined.

Copper iodide (CuI) thin films were grown on Si(100) substrates using a copper film iodination reaction method. It was found that γ-CuI films have a uniform and dense microstructure with (111)-orientation. Transmission spectra indicated that CuI thin films have an average transmittance of about 60% in the visible range and the optical band gap is 3.01 eV. By checking the effect of the thickness of the Cu films and annealing condition on the photoluminescence (PL) character of CuI films, the luminescence mechanisms of CuI have been comprehensively analyzed, and the origin of different PL emissions are proposed with Cu vacancy and iodine vacancy as defect levels.

All-inorganic perovskite CsPbBr3 thin films have been prepared on Si (100) substrate by a pulsed-laser deposition (PLD) technique, and the morphology, structure, absorbance, and photoluminescence properties of CsPbBr3 thin films are investigated. A photodetector based on CsPbBr3/n-Si heterojunction has been fabricated, and the performances of the device are characterized. The heterojunction photodetector exhibits diode-like rectifying behavior, and the photocurrent-to-dark-current ratio and peak responsivity of the heterojunction are approximately 168.5 and 0.6 A/W (−5 V, 520 nm), respectively. Furthermore, the CsPbBr3/n-Si heterojunction photodetector exhibits fast response and recovery times. With good optoelectronic properties, CsPbBr3 thin films prepared by PLD should be widely applicable to high-performance photodetectors and other optoelectronic devices.

ZnO/diamond-like carbon (DLC) thin films are deposited by pulsed laser deposition (PLD), and the room-temperature photoluminescence (PL) is investigated. Using a fluorescence spectrophotometer, we obtain the PL spectra of DLC/Si and ZnO/Si thin films deposited at different substrate temperatures. The ZnO/DLC thin films show a broadband emission almost containing the entire visible spectrum. The Gaussian fitting curves of PL spectra reveal that the visible emission of ZnO/DLC thin films consists of three peaks centered at 381 nm, 526 nm and 682 nm, which are attributed to the radiative recombination of ZnO and DLC, respectively. The Commission International de l’Eclairage (CIE) 1931 (x, y) chromaticity space of ZnO/DLC thin films indicates that the visible PL spectrum is very close to the standard white-light region.

Cutinase is described as playing various roles in fungal–plant pathogen interactions, such as eliciting host-derived signals, fungal spore attachment and carbon acquisition during saprophytic growth. However, the characteristics of the cutinase genes, their expression in compatible interactions and their roles in pathogenesis have not been reported in Curvularia lunata, an important leaf spot pathogen of maize in China. Therefore, a cutinase gene family analysis could have profound significance. In this study, we identified 13 cutinase genes (ClCUT1 to ClCUT13) in the C. lunata genome. Multiple sequence alignment showed that most fungal cutinase proteins had one highly conserved GYSQG motif and a similar DxVCxG[ST]-[LIVMF](3)-x(3)H motif. Gene structure analyses of the cutinases revealed a complex intron–exon pattern with differences in the position and number of introns and exons. Based on phylogenetic relationship analysis, C. lunata cutinases and 78 known cutinase proteins from other fungi were classified into four groups with subgroups, but the C. lunata cutinases clustered in only three of the four groups. Motif analyses showed that each group of cutinases from C. lunata had a common motif. Real-time PCR indicated that transcript levels of the cutinase genes in a compatible interaction between pathogen and host had varied expression patterns. Interestingly, the transcript levels of ClCUT7 gradually increased during early pathogenesis with the most significant up-regulation at 3 h post-inoculation. When ClCUT7 was deleted, pathogenicity of the mutant decreased on unwounded maize (Zea mays) leaves. On wounded maize leaves, however, the mutant caused symptoms similar to the wild-type strain. Moreover, the ClCUT7 mutant had an approximately 10 % reduction in growth rate when cutin was the sole carbon source. In conclusion, we identified and characterized the cutinase family genes of C. lunata, analyzed their expression patterns in a compatible host–pathogen interaction, and explored the role of ClCUT7 in pathogenicity. This work will increase our understanding of cutinase genes in other fungal–plant pathogens.

T. koningii, T. harzianum, T. asperellum, T. longibrachiatum, and T. viride were analyzed using liquid chromatography-tandem mass spectrometry to determine whether melatonin is present. Results showed that there were abundant amounts of endogenous melatonin in five Trichoderma species, but no melatonin was found in any of the culture filtrates. T. asperellum had the highest amount of melatonin (27.588 ± 0.326 μg g(-1) dry mass), followed by T. koningii, T. harzianum, T. longibrachiatum, and T. viride. The endogenous melatonin content of T. asperellum in controlled-stress growth conditions was also detected. The data showed that chemical stressors (CdCl2 , CuSO4 , and H2 O2 ) provoked an increase in endogenous melatonin levels. CdCl2 had the highest stimulatory effect on melatonin production, as the product reached reaching up to three times the melatonin content of the control. NaCl stimulated a decrease of melatonin. Acidic conditions (pH 3 and pH 5) as well as slightly alkaline conditions (pH 9) resulted in an increase in the melatonin content, whereas pH11 resulted in a significant decrease in the melatonin content, only 12.276 ± 0.205 μg g(-1) dry mass. The current study is first to report melatonin content and the change of melatonin content under different stress situations in Trichoderma spp.

We present the preparation of C54 TiSi 2 nanoislands on Si (1 1 1) with a method of the pulsed laser deposition of titanium oxide thin films. The TiO 2 thin films with nominal thicknesses of 1 nm on Si (1 1 1) were annealed at 850 °C for about 4 h in situ. The X-ray diffraction patterns and the X-ray photoelectron spectra indicate that the nanoislands are in C54 TiSi 2 phase. The characterization using a scanning tunneling microscope shows that the nanoislands with triangular, polygonal and rod-like shapes on Si (1 1 1) exhibit the Volmer–Weber growth mode. The sizes of the polygonal islands distribute in two separated ranges. For the small islands, they have a narrow lateral size distribution centered at 4 nm and a height range in 0.6–3.6 nm, while for the large islands, their lateral sizes are in the range of 12–40 nm and the heights in the range of 4–9 nm. The sizes of the well-shaped triangular islands are intermediate with the lateral sizes in range of 5–20 nm and the heights of 2–3.5 nm. The rod-like islands are about 50–200 nm in length, 5 nm in height and about 15–20 nm in width. The origination of the various shapes of the nanoislands is attributed to the symmetry of Si (1 1 1) substrate and the lattice mismatch between the C54 TiSi 2 and the Si (1 1 1) surface.

We present the growth of textured TiO2 thin films on muscovite mica using pulsed laser deposition. Atomic force microscopy, scanning electron microscopy, X-ray photoemission spectroscopy, and transmission electron microscopy were used to characterize the TiO2 films. Quasi-periodic wavy and comb-like buckles were observed. Below a critical thickness of about 25 nm, TiO2 films were relatively smooth, and buckles began to form when the nominal thickness of TiO2 films was larger than 25 nm. Co-existence of wavy and comb-like quasi-periodic buckles was observed when the nominal thickness of TiO2 films was larger than 100 nm. The film stress is compressive due to the competition of the tensile stress from the lattice mismatch and the growth stress. The buckle delamination occurred when the compressive stress overcome the adhesion strength of the TiO2 films on mica. A value of adhesion strength around 0.9 MPa for TiO2 on mica is obtained. The symmetric domains of buckles are assigned to the anisotropic lattice mismatch for TiO2 on mica.

Self-assembled monolayers of novel C60 derivative, N-3-γ-pyridyl Aza[60]fulleroid (C60Py), on Au(111) were studied by a scanning tunneling microscope under ultrahigh vacuum (UHV). C60Py molecules were assembled on Au (111) via pyridyl nitrogen-Au interaction. The sole assembly of C60Py molecules on Au (111) only exhibited randoml aggregation of C60Py even the films were annealed at 50 and 105°C. By co-assembling with benzyl mercaptan (BM), the C60PyBM films showed highly dense aggregation, but C60Py assemblies still had disordered structure. After the co-assembled C60Py-BM films were annealed at 50°C, BM molecules were partially desorbed, but the assembly of C60Py remained without obvious change. After the co-assembled C60Py-BM films were further annealed at 105°C, the C60Py monolayers with ordered structure were obtained, while the BM molecules were nearly thoroughly desorbed from the surface. Here, the BM molecules play a key role as a surfactant in the formation of the ordered C60Py monolayer.

GaN is demonstrated to be an ideal anode for Li-ion batteries (LIBs) for the first time. Amorphous GaN@Cu nanorods (a-GaN@Cu) freestanding electrode is designed via a low-temperature pulsed laser deposition method, which exhibits prominent rate capability and untralong lifespan as an anode for LIBs. With porous interconnected metal nanorods substrate to improve the structure integrity and electronic conductivity, the a-GaN@Cu electrode delivers a capacity recovery of 980 mAh g−1 after 150 cycles from 0.25 to 6.25 A g−1 and a high discharge capacity of 509 mAh g−1 after 3000 cycles at 10.0 A g−1. The lithium storage in the a-GaN is also systematically studied, which suggests a redox reaction mechanism.

n-ZnO/p-GaN heterojunction light emitting diodes with different interfacial layers were fabricated by pulsed laser deposition. The electroluminescence (EL) spectra of the n-ZnO/p-GaN diodes display a broad blue-violet emission centered at 430 nm, whereas the n-ZnO/ZnS/p-GaN and n-ZnO/AlN/p-GaN devices exhibit ultraviolet (UV) emission. Compared with the AlN interlayer, which is blocking both electron and hole at hetero-interface, the utilization of ZnS as intermediate layer can lower the barrier height for holes and keep an effective blocking for electron. Thus, an improved UV EL intensity and a low turn-on voltage (~5V) were obtained. The results were studied by peak-deconvolution with Gaussian functions and were discussed using the band diagram of heterojunctions.

ZnS:Mn thin films are grown on GaN substrates by pulsed laser deposition. The structure, morphology and optical properties are investigated by x-ray diffraction, scanning electron microscopy and photoluminescence (PL). The obtained ZnS:Mn thin films are grown in preferred orientation along β-ZnS (111) direction corresponding to crystalline structure of cubic phase. The deposition temperature has an obvious effect on the structure, surface morphology and optical properties of ZnS:Mn thin films. PL measurements show that there are two emission bands located at 440 nm and 595 nm when the films are deposited at temperatures from 100°C to 500°C. The relative integrated intensity of the blue emission and orange-red emission is determined by the deposition conditions. At the proper deposition temperature of 300°C, the color coordinate is closest to (0.33, 0.33). The ZnS:Mn films on GaN substrates can exhibit white light emission.

Heterojunction light-emitting diodes (LEDs) based on arrays of ZnO nanorods were fabricated on p-GaN films by the hydrothermal method. Without any phosphors, white-light electroluminescence (EL) from ZnO nanorods/p-GaN heterojunction LEDs operated at reverse breakdown bias was observed. The EL spectra are composed of an ultraviolet (UV) emission centered at 382 nm, a blue light located at 431 nm and a broadband yellow–green light at around 547 nm, which originated from band-edge emission in ZnO, the Mg acceptor levels in p-GaN and the deep-level states near the ZnO/GaN interface, respectively. The chromaticity coordinates of EL spectrum are very close to the (0.333, 0.333) of standard white light. The origin of these emissions has been discussed and the tunneling effect in the interface is probably the mechanism to explain EL emission.

n-ZnO : Ga/p-GaN heterojunction light-emitting diodes with different interfacial layers are fabricated by pulsed laser deposition. All the devices demonstrate nonlinear rectifying behaviour. Due to the formation of Ga2O3 interfacial layers, n-ZnO : Ga/p-GaN exhibits strong ultraviolet emission centred at 382 nm and blue emission centred at 423 nm. Compared with a n-ZnO : Ga/MgO/p-GaN light-emitting diode, the turn-on voltage of n-ZnO : Ga/p-GaN with a Ga2O3 interfacial layer drops down to 7.6 V and the ultraviolet emission intensity is enhanced. Detailed electroluminescence mechanisms influenced by the interfacial layer are discussed using the band diagram of heterojunctions.

ZnO nanorods have been prepared by a hydrothermal method on an unetched GaN-based light-emitting diode (LED) wafer. Without any etching steps or complex lithography, high brightness LED devices have been fabricated. The devices exhibited lighting up under both forward and reverse biases, and the electroluminescence spectra were dominated by GaN multiquantum well emission. Compared with that from a conventional GaN LED, the light output intensity was enhanced by the ZnO nanorods.