Induced growth of high quality ZnO thin filmsby crystallized amorphous ZnO

This paper reports the induced growth of high quality ZnO thin film by crystallized amorphous ZnO. Firstly amorphous ZnO was prepared by solid-state pyrolytic reaction, then by taking crystallized amorphous ZnO as seeds （buffer layer）, ZnO thin films have been grown in diethyene glycol solution of zinc acetate at 80 ℃. X-ray Diffraction curve indicates that the films were preferentially oriented [001] out-of-plane direction of the ZnO. Atomic force microscopy and scanning electron microscopy were used to evaluate the surface morphology of the ZnO thin film. Photoluminescence spectrum exhibits a strong ultraviolet emission while the visible emission is very weak. The results indicate that high quality ZnO thin film was obtained.     

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.     

Absorption Spectra and Ionic Conductivity of RbxCs1-xAg4I5 Superionic Conductors Thin Films

A series of RbxCs1-xAg4I5(x=0-1) thin films were grown by vacuum evaporation on NaCI crystal substrates at 350K. The absorption spectra of these films were measured at 80K in the wavelength range from 240nm to 400nm. It is shown that superionic conductor thin films of quaternary compound Rb0.5Cs0.5Ag4I5 and ternary compound RbAg415 can be obtained at x=0.5-0.6 and x=0.7-1, respectively. At x=0.65, the combined compound film of the mixture of 30mol% RbAg4I5 and 70mol% Rb0.5Cs0.5Ag4I5 is presented. Then, based on the spectral positions of the A1 and A2 peaks, we determined that the Rb0.5Cs0.5Ag4I5 exciton coupling energy Rex is 0.21eV, the forbidden zone width Eg is 3.82eV and the exciton radius aex is 0.70hm. Furthermore, the ionic conductivities of superionic conductor thin films of RbAg4I5 and Rb0.5Cs0.5Ag4I5 and their mixture film are investigated, respectively, in the temperature range 303 K-393K.     

Effects of annealing rate and morphology of sol–gel derived ZnO on the performance of inverted polymer solar cells

The effects of annealing rate and morphology of sol–gel derived zinc oxide(ZnO)thin films on the performance of inverted polymer solar cells(IPSCs)are investigated.ZnO films with different morphologies are prepared at different annealing rates and used as the electron transport layers in IPSCs.The undulating morphologies of ZnO films fabricated at annealing rates of 10 C/min and 3 C/min each possess a rougher surface than that of the ZnO film fabricated at a fast annealing rate of 50 C/min.The ZnO films are characterized by atomic force microscopy(AFM),optical transmittance measurements,and simulation.The results indicate that the ZnO film formed at 3 C/min possesses a good-quality contact area with the active layer.Combined with a moderate light-scattering,the resulting device shows a 16%improvement in power conversion efficiency compared with that of the rapidly annealed ZnO film device.     

Magnetic Properties and Nanostructures of FePtCu：C Thin Films with FePt Underlayers

Magnetic properties and nanostructures of FePtCu：C thin films with FePt underlayers （ULs） are studied. The effect of FePt ULs on the orlentation and magnetic properties of the thin films are investigated by adjusting FePt UL thicknesses from 2nm to 14nm. X-ray diffraction （XRD） scans reveal that the orientation of the films is dependent on FePt UL thickness. For a 5-nm FePtCu：C nanocomposite thin film with a 2-nm FePt UL, the coercivity is 6.S KOe, the correlation length is 59 nm, the desired face-centred-tetragonal （fct） ordered structure [Llo phase] is formed and the c axis normal to the film plane [（001） texture] is obtained. These results indicate that the beffer orientation and magnetic properties of the films can be tuned by decreasing the thockness of the FePt UL.     

Room-Temperature Ferromagnetism in Zn1-xMnxO Thin Films Deposited by Pulsed Laser Deposition

Zn1-xMnxO （x = O.Olq3.1） thin films with a Curie temperature above 300K are deposited on Al2O3 （0001） substrates by pulsed laser deposition. X-ray diffraction （XRD）, ultraviolet （UV）-visible transmission and Raman spectroscopy are employed to characterize the microstructural properties of these films. Room temperature ferromagnetism is observed by superconducting quantum interference device （SQUID）. The results indicate that Mn doping introduces the incorporation of Mn^2＋ ions into the ZnO host matrix and the insertion of Mn^2＋ ions increases the lattice defects, which is correlated with the ferromagnetism of the obtained films. The doping concentration is also proven to be a crucial factor for obtaining highly ferromagnetic Zn1-xMnxO films.     

Effects of doping concentration on properties of Mn-doped ZnO thin films

This paper reports that the radio frequency magnetron sputtering is used to fabricate ZnO and Mn-doped ZnO thin films on glass substrates at 500 C. The Mn-doped ZnO thin films present wurtzite structure of ZnO and have a smoother surface, better conductivity but no ferromagnetism. The x-ray photoelectron spectroscopy results show that the binding energy of Mn2p3/2 increases with increasing Mn content slightly, and the state of Mn in the Mn-doped ZnO thin films is divalent. The chemisorbed oxygen in the Mn-doped ZnO thin films increases with increasing Mn doping concentration. The photoluminescence spectra of ZnO and Mn-doped ZnO thin films have a similar ultraviolet emission. The yellow green emissions of 4 wt.% and 10 wt.% Mn-doped thin films are quenched, whereas the yellow green emission occurs because of abundant oxygen vacancies in the Mn-doped ZnO thin films after 20 wt.% Mn doping. Compared with pure ZnO thin film, the bandgap of the Mn-doped ZnO thin films increases with increasing Mn content.     

Structure Properties of MgxZn1-xO Films Deposited at Low Temperature

MgxZn1-xO films (x = 0.23) have been prepared on silicon substrates by radio-frequency magnetron sputtering at 80℃. The structure properties of Mgx Zn1-xO films are studied using x-ray diffraction (XRD), high-resolution transmission electron microscopy (HRTEM), x-ray photoelectron spectroscopy and Raman spectra. The analysis of XRD and HRTEM indicates that the Mgx Zn1-xO films have hexagonal wurtzite single-phase structures and a preferred orientation with the c axis perpendicular to the substrates. Raman spectra of ZnO and MgxZn1-xO films reveal that the MgxZn1-xO films have not only the hexagonal wurtzite structure but also higher crystalline quality than ZnO films.     

Growth of n-type ZnO thin films by using mixture gas of hydrogen and argon

High-quality oxide semiconductor ZnO thin films were prepared on single-crystal sapphire and baAlO3 substrates by pulsed laser deposition （PLD） in the mixture gas of hydrogen and argon. Low resistivity n-type ZnO thin films with smoother surface were achieved by deposition at 600℃ in 1Pa of the mixture gas. in addition, ferromagnetism was observed in Co-doped ZnO thin films and rectification Ⅰ - Ⅴ curves were found in p-GaN/n-ZnO and p-CdTe/n-ZnO heterostructure junctions. The results indicated that using mixture gas of hydrogen and argon in PLD technique was a flexible method for depositing high-quality n-type oxide semiconductor films, especially for the multilayer thin film devices.     

Photoluminescence and Optically Pumped Ultraviolet Lasing from Nanocrystalline ZnO Thin Films Prepared by Thermal Oxidation of High—Quality ZnS Thin Films

We present a simple and useful method for preparing high-quality nanocrystalline ZnO thin films,i.e.the thermal oxidation of high-quality ZnS films prepared by the low-pressure metal-organic chemical vapour deposition technique.The x-ray diffraction measurements reveal that the nanocrystalline ZnO has a hexagonal wurtzite structure.Raman spectra show that the longitudinal optical phonon with the E1-mode appears at 578 cm^-1.The multiple phonon scattering process is also observed,indicating the formation of a high-quality nanocrystalline ZnO thin film.The photoluminescence spectrum has a single emission peak at 3.264eV from the free-exciton mission,under the condition of low excitation power at room temperature.However,when excitation intensities exceed the threshold of 150kW/cm^2,a new and narrow peak emerges at lower energies,which are attributed to exciton-exciton collisions,and is called the P line.The intensity of this peak increases superlinearly with the pumping power over a threshold value.This supplies strong evidence of stimulated emission.The multiple longitudinal cavity modes observed in the stimulated emission spectrum indicate the successful realization of optically pumped lasing from nanocrystalline ZnO films at room temperature.