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Cesium lead halide perovskites have shown great potential applications in photoelectric devices because of their high quantum efficiency, good stability, and tunable bandgap. Herein, we prepared CsPbBr3 microwires with a high crystal quality, smooth surface, and rectangular cross section via the solution method. The as-prepared microwires presented a high quality whispering gallery mode lasing with a low threshold of 9.1 μJ cm−2 and a high quality factor of ∼3000. Furthermore, we obtained the alloys of CsPbClxBr3−x (0 < x

Stoichiometric Co3O4 porous nanotubes have been synthesized through a simple modified microemulsion method. The structural and the chemical information of the as-grown nanotubes have been investigated by means of x-ray diffraction, electron microscopy, electron energy loss spectroscopy, and dynamic force microscopy. The results reveal that the as-grown materials are formed by concentric stacking of Co3O4 (111) planes or weaved porous nanotubes with diameters ranging from tens to ∼200nm and sidewall thickness ranging from 2to∼20nm. Magnetic property of the sample demonstrates a magnetic transition temperature at 8.4K, indicating macroscopic quantum confinement effects from the sidewall thickness of the porous nanotube.

ZnO nanowires were obtained through evaporation of zinc powders under a low temperature of 400 °C. These ZnO nanowires, in the diameter of ∼10 nm, were long and curved with lengths of tens of micrometers. High-resolution transmission electron microscopy showed these ZnO nanowires were mostly crystalline structure; however, the kink parts contained dislocations and stacking faults. Furthermore, the movement of dislocations was observed in the kink parts under e-beam irradiation. Photoluminescence and Raman spectra show that there exist oxygen vacancies in the ZnO nanowires. Possible reasons for the growth and properties of ZnO nanowires were discussed.

High-density ZnO nanowires (ZnONWs) were aligned onto Au-catalyzed Si substrate through a simple low-temperature physical vapor deposition method. Scanning electron microscope (SEM) observations, x-ray diffraction (XRD) analysis, and photoluminescence spectra showed that the ZnONWs were single-crystalline, with a hexagonal wurzite structure. All of the results inferred from the SEM observations, the XRD rocking curves, and the Raman spectra for the investigated samples confirm that the ZnONWs are well aligned and c-axis oriented. The Raman spectra also indicated that the ZnONWs on Si substrates are under the biaxial compressive stress. Since it takes the advantage of low-cost, easily controlled deposition spot (due to the selective deposition trait of the Au layer), potential for scale-up production, and ability to integrate with Si substrate, this technique has a potential in future for fabricating the ZnONW array-based optoelectronic devices.

Diluted magnetic semiconductor Zn1−xMnxO nanowires were synthesized via an in situ doping of manganese in ZnO nanowires using vapor phase growth at 500 °C. The maximum content of the manganese in the ZnO is around 13 at. %, approaching the maximum thermal equilibrium limit of Mn solubility in ZnO at the growth temperature. Structure and composition analysis revealed that the manganese was doped into the lattice structure, forming solid solution instead of precipitation. Magnetic property measurements revealed that the as-doped Zn1−xMnxO nanowires exhibit ferromagnetic behavior with Curie temperature around 37 K.

A large quantity of nanosized ZnO tubular structures was prepared using a very simple thermal evaporation of mixed Zn–ZnO powders under a wet oxidation condition. The ZnO nanotubes have a hollow core with crystalline wall of 8–20 nm in thickness. Optical properties of ZnO nanotubes were studied at room temperature. Raman peaks arising from the ZnO nanotubes were analyzed, which correspond well to that of the bulk ZnO sample. The photoluminescence measurements of ZnO nanotubes revealed an intensive UV peak at 377 nm corresponding to the free exciton emission, and a broad peak at about 500 nm arising from defect-related emission.

Well-aligned arrays of ZnO nanoneedles were fabricated using a simple vapor phase growth. The diameters of the nanoneedle tips are as small as several nanometers, which is highly in favor of the field emission. Field-emission measurements using the nanoneedle arrays as cathode showed emission current density as high as 2.4 mA/cm2 under the field of 7 V/μm, and a very low turn-on field of 2.4 V/μm. Such a high emission current density is attributed to the high aspect ratio of the nanoneedles. The high emission current density, high stability, and low turn-on field make the ZnO nanoneedle arrays one of the promising candidates for field-emission displays.

Stoichiometric ZnSe nanowires have been synthesized through a vapor phase reaction of zinc and selenium powder on the (100) silicon substrate coated with a gold film of 2 nm in thickness. The microstructures and the chemical compositions of the as-grown nanowires have been investigated by means of electron microscopy, the energy dispersive spectroscopy, and Raman spectroscopy. The results reveal that the as-grown materials consist of ZnSe nanowires with diameters ranging from 5 to 50 nm. Photoluminescence of the sample demonstrates a strong green emission from room temperature down to 10 K. This is attributed to the recombination of electrons from conduction band to the medium deep Au acceptors.

Anomalous Hall effect at room temperature in perpendicular Hall balance with a core structure of [Pt/Co]4/NiO/[Co/Pt]4 has been tuned by functional CoO layers, where [Pt/Co]4 multilayers exhibit perpendicular magnetic anisotropy. A giant Hall resistance ratio up to 69 900% and saturation Hall resistance (RSP) up to 2590 mΩ were obtained in CoO/[Pt/Co]4/NiO/[Co/Pt]4/CoO system, which is 302% and 146% larger than that in the structure without CoO layers, respectively. Transmission electron microscopy shows highly textured [Co/Pt]4 multilayers and oxide layers with local epitaxial relations, indicating that the crystallographic structure has significant influence on spin dependent transport properties.

TbMnO3 thin films with different crystallographic orientations were deposited epitaxially on LaAlO3 [100] and SrTiO3 [100] single crystal substrates by using pulsed laser deposition. Magnetization measurements were performed along the [110], [−110], and [001] directions of the films. Obvious magnetic anisotropy and low temperature ferromagnetism were found. Transitions at T ∼ 10, 32, 120, and 125 K along different directions are observed. The susceptibility anomalies, remarkably anisotropic, are discussed on the frame of the domain wall and strain-induced distortion. Particularly, the lattice mismatch and the anisotropic thermal expansion between the films and substrates are likely responsible for the distortion behaviors. Published version

Ultrathin ZnS nanobelts were assembled by ultrasmall nanocrystals with oriented self assembly, which were then transformed into their single-crystal counterparts by thermal treatment in N2. ZnO/ZnS heterostructures were also obtained at elevated temperature in open air, where well aligned ZnO nanocones were grown along the ZnS nanobelts with a definite orientation relationship described as [0001]ZnS∥[0001]ZnO and (101¯0)ZnS∥(101¯0)ZnO. Mixed transition and tuned band gaps of the heterostructure were experimentally observed, which was in good agreement with the theoretical predications and can be interpreted based on the model of a strained staggered type-II band structure.

To improve the stability of organic multifunctional materials and enhance the ON/OFF ratio, a donor-π-acceptor molecule with the triphenylamine (TPA) unit is designed and synthesized. The TPA unit can effectively stabilize the charge transferred state, and the thin film shows excellent bistable electronic switching behavior with high ON/OFF current ratio of about 105. Meanwhile, reversible and stable nanometer-scale data storage is realized on the thin film by applying pulsed voltages, and optical information storage is achieved simultaneously by utilizing fluorescence changes under UV irradiation.

The Au∕Nb-1.0wt%-doped SrTiO3 junctions were successfully fabricated by magnetic controlled sputtering and annealing process. Backward diodelike behaviors were observed in as-prepared junction and the one annealed at 350°C. Transition to Schottky behavior was found in the junction annealed at 750°C; the Schottky junction shows linear capacitance-voltage (C−2-V) relationship in the reverse condition with barrier heights determined to be 1.6eV. The results of current-voltage (I-V) measurements reveal that high temperature annealing can alter interface barrier and thereby ameliorate the stability of leakage current remarkably.

Short-range order in amorphous intergranular films in SiC hot pressed with Al, B, and C additives was recognized with autocorrelation processing of high-resolution electron microscopy images. The short-range order corresponds to Al–O–C tetrahedra formed near the SiC matrix grains. In situ heating high-resolution transmission electron microscopy study demonstrated that the amorphous-to-crystalline transformation in the amorphous Al–O–C intergranular films started from nucleation and local growth of the short-range order structure.

We demonstrate the synthesis of single-crystalline star-shaped ZnO microcrystals with six arms by a simple solution method. Microscopic and diffraction data reveal that the as-grown products have a wurtzite structure. Each arm of the ZnO microstars has a sharp tip of several nanometers. Under moderate optical excitation, stimulated emission was observed at 388.4nm with a full width at half-maximum (FWHM) of less than 3nm and a threshold of 318kW∕cm2.