Effect of Post-Annealing on Microstructural and Electrical Properties of N^＋Ion-Implanted into ZnO：In Films

We fabricate p-type conductive ZnO thin films on quartz glass substrates by codoping of In-N using radio frequency magnetron sputtering technique together with the direct implantation of acceptor dopants （nitrogen）. The effects of thermal annealing on the structure and electrical properties of the ZnO films are investigated by an x-ray diffractometer （XRD） and a Hall measurement system. It is found that the best p-type ZnO film subjected to annealed exhibits excellent electrical properties with a hole concentration of 1.22 × 10^18 cm^-3, a Hall mobility of 2.19 cm^2 V^-1 s^- 1, and a low resistivity of about 2.33 Ωcm, indicating that the presence of In may facilitates the incorporation of N into ZnO thin films.     

Effect of Annealing on Microstructure and Electrical Characteristics of Doped Poly （3-Hexylthiophene） Films

The effect of annealing on the microstructure and electrical characteristics of poly （3-hexylthiophene） （P3HT） films doped with very small amounts of the electron acceptor 2,3,5,6-tetrafluoro-7,7,8,8-tetracyanoquinodimethane （F4-TCNQ） is studied. X-ray diffraction and UV-vis spectrum studies show that unlike the pure P3HT film, the thermal treatment on the doped fihns under an Ar atmosphere can effectively enhance the crystalline order of P3HT films, as well as successfully facilitate the orientation of the polymer chains. This improvement is attributed to the electrostatic force between P3HT and F4-TCNQ molecules. This force induces the polymer chains to crystallize and orient during the annealing process. As a result, annealing significantly improves performance, especially for the Ion/Ioff ratio of the TFTs based on the doped P3HT films.     

Oxygen Pressure Dependence of Properties of Epitaxial LaAlO3 Films Grown on Si （100）

Heteroepitaxial LaAlO3 films were grown on a SrTiO3/Si (100) substrate by laser molecular beam epitaxy under different oxygen pressures, and their properties such as crystallinity and electrical characteristics were experimentally investigated using the various measurement methods. The results show that most properties depend mainly on the deposition oxygen pressure. The crystallinity and the C-V and I-V characteristics can be greatly improved with the increasing oxygen deposition pressure. Moreover, after annealed at 1050~C in N2 ambient, the C-V and I-V characteristics of LAO films deposited at the lower oxygen pressure are also improved due to the decrease of oxygen vacancies in LAO films.     

The Near Surface Morphology of P3HT：PCBM Blend Films Studied by Near-Edge X-Ray Absorption Fine Structure

The microstructure of poly（3-hexylthiophene） （P3HT） and [6,6]-phenyl-C61 butyric acid methyl ester （PCBM） blends with various annealing temperatures are investigated in detail by the near-edge x-ray absorption fine structure. Under higher anneMing temperature （Tanneal ≥ 160℃）, P3HT shows an unusual fluidity and aggregation in the surface. After annealing, the enrichment polymer component recrystallizes and forms a single P3HT phase layer in the surface of blend films. Moreover, it gives direct evidence of the PCBM content diffusing to the near surface of blend films during annealing treatment. These findings are beneficial to improving the morphology of polymer/fullerene blend films.     

Effects of Substrate Temperature and Nitrogen Pressure on Growth of AIN Films by Pulsed Laser Deposition

Highly oriented aluminium nitride （AIN） films are grown on p-Si （100） substrates by pulsed laser deposition, and their characteristics of structure and composition are studied by x-ray diffraction, Fourier transform infrared spectroscopy and scanning electron microscopy. The results show that the deposited films exhibit good crystalline properties with a sharp x-ray diffraction peak at 2θ= 33.15 ° corresponding to AIN h （100） crystalline orientation. The influences of substrate temperature and ambient nitrogen （N2） pressure on the crystallinity of A1N films are remarkable. At room temperature, when the ambient N2 pressure arises from 5 × 10^-6 Pa to 5 Pa, the crystallinity of the film becomes better. When the substrate temperature is 600℃, the film has the best crystallinity at 0.05 Pa. Furthermore, the effects of substrate temperature and ambient N2 pressure on the combination of A1-N bonds and surface morphology of AIN films are also studied.     

Magnetizations and magneto-transport properties of Ni-doped PrFe03 thin films

The present study reports the magnetizations and magneto-transport properties of PrFel_xNixO3 thin films grown by pulsed laser ablation technique on LaA103 snbstrates. From DC M/H plots of these films, weak ferromagnetism or ferrimagnetism behaviors are observed. With Ni substitution, reduction in saturation magnetization is also seen. With Ni doping, variations in saturation field （Hs）, coercive field （Hc）, Weiss temperature （0）, and effective magnetic moment （Pelf） are seen. A small change of magnetoresitance with application of higher field is observed. Various essential parameters like density of state （Nf） at Fermi level, Mott＇s characteristic temperature （To）, and activation energy （Ea） in the presence of and in the absence of magnetic field are calculated. The present observed magnetic properties are related to the change of Fe-O bond length （causing an overlap between the oxygen p orbital and iron d orbital） and the deviation of the Fe-O-Fe angle from 180~. Reduction of magnetic domain after Ni doping is also explored to explain the present observed magnetic behavior of the system. The influence of doping on various transport properties in these thin films indicates a distortion in the lattice structure and single particle band width, owing to stress-induced reduction in unit cell volume.     

Growth and photoluminescence properties of inclined ZnO and ZnCoO thin films on SrTiO_3（110） substrates

ZnO thin film growth prefers different orientations on the etched and unetched SrTiO 3（STO）（110） substrates.Inclined ZnO and cobalt-doped ZnO（ZnCoO） thin films are grown on unetched STO（110） substrates using oxygen plasma assisted molecular beam epitaxy,with the c-axis 42 inclined from the normal STO（110） surface.The growth geometries are ZnCoO[100]//STO[110] and ZnCoO[111]//STO[001].The low temperature photoluminescence spectra of the inclined ZnO and ZnCoO films are dominated by D 0 X emissions associated with A 0 X emissions,and the characteristic emissions for the 2 E（2G）→ 4A2（4F） transition of Co 2＋ dopants and the relevant phonon-participated emissions are observed in the ZnCoO film,indicating the incorporation of Co 2＋ ions at the lattice positions of the Zn 2＋ ions.The c-axis inclined ZnCoO film shows ferromagnetic properties at room temperature.     

Growth-Parameter Spaces and Optical Properties of Cubic Boron Nitride Films on Si（001）

Cubic boron nitride （c-BN） films were deposited on Si（001） substrates in an ion beam assisted deposition （IBAD） system under various conditions, and the growth parameter spaces and optical properties of c-BN films have been investigated systematically. The results indicate that suitable ion bombardment is necessary for the growth of c-BN films, and a well defined parameter space can be established by using the P/a-parameter. The refractive index of BN films keeps a constant of 1.8 for the c-BN content lower than 50%, while for c-BN films with higher cubic phase the refractive index increases with the c-BN content from 1.8 at χc =50% to 2.1 at χc = 90%. Furthermore, the relationship between n and p for BN films can be described by the Anderson-Schreiber equation, and the overlap field parameter γ is determined to be 2.05.     

Effect of Temperature on Structural and Magnetic Properties of Laser Ablated Iron Oxide Deposited on Si（100）

We fabricate Fe3O4 thin films on Si（100） substrates at different temperatures using pulsed laser deposition, and study the effect of annealing and deposition temperature on the structural and magnetic properties of Fe3O4 thin films. Subsequently, the films are characterized by x-ray diffraction （XRD）, scanning electron microscopy （SEM） and vibrating sample magnetometery （VSM）. The XRD results of these films confirm the presence of the Fe3O4 phase and show room-temperature ferromagnetism, as observed with VSM. We demonstrate the optimized deposition and annealing conditions for an enhanced magnetization of 854 emu/cm3 that is very high when compared to the bulk sample.     

Electrical Response of Flexible Vanadyl-Phthalocyanine Thin-Film Transistors under Bending Conditions

Flexible vanadyl-phthalocyanine （VOPc） thin-film transistors are fabricated by the weak epitaxy growth （WEG） method. The devices show a mobility of 0.5 cm2/Vs, an on/off ratio of 105 and a low leakage current of 10-9 A. The performances exhibit strong dependence on bending conditions and reversible change can be found when the bending strain is less than 1.5%. This results from the change of the trap density calculated by subthreshold slopes. The results indicate that VOPc films fabricated by the WEG method have good durability to flexing and possess great potential in flexible electronics.