Search

Abstract: Zinc oxide (ZnO) thin film was grown on CaF2 (11–21) substrate by metalorganic vapor phase epitaxy (MOVPE) and the structure, surface morphology and the opto-electrical properties of the film were investigated. It was found that preferential c-axis oriented ZnO film was highly transparent and quite smooth. In photoluminescence (PL) spectrum at 10K, the neutral donor bound exciton (D0X) emission was identified at 3.362eV (I4), the neutral acceptor bound exciton (A0X) emission at 3.346eV (I9). Free A- and B-exciton emissions at 3.374eV and 3.386eV, respectively, as well as the phonon replicas of free A-exciton and D0X were also observed, indicating high optical quality of the ZnO film. Temperature-dependent PL spectra demonstrated that the free exciton emission was dominant at a temperature larger than 215K. Hall measurement showed that the ZnO/CaF2 film exhibited n-type conduction, with the resistivity of 114Ωcm and the Hall mobility of 15.7cm2/Vs. [Copyright &y& Elsevier]

Highlights: [•] We have demonstrated the chemical reaction, charge and energy transfer process using photoelectron spectroscopy for near-infrared organic light-emitting diodes. [•] Based on the result of this paper, we can achieve the optimal device efficiency by certain of ErF3 dopant concentration, which is useful for the research of NIR-OLED. [•] The study on the electroluminescence mechanism is crucial for the applying of ErF3 doped NIR-OLED. [Copyright &y& Elsevier]

Abstract: In this paper ZnO films are grown on GaAs/Al2O3 substrates at different temperature by metal-organic chemical vapor deposition (MOCVD). The GaAs/Al2O3 substrates are formed by depositing GaAs layer (∼35nm) on the Al2O3 substrate. The results of X-ray photoelectron spectroscopy (XPS) and X-ray diffraction (XRD) demonstrate that most of the Ga and As atoms form Ga–As bond and the GaAs layer does not present any orientation. The characters of the ZnO films grown on GaAs/Al2O3 substrates are investigated by XRD, photoluminescence (PL), atomic force microscopy (AFM) and Raman scattering. Compared with ZnO film grown on Al2O3 substrate, ZnO film prepared by our fabrication scheme has good crystal and optical quality. Meanwhile its grain size becomes bigger according to the AFM image. Raman analysis indicates that the intrinsic defects and the in-plane tensile stress are obviously reduced in ZnO/GaAs/Al2O3 samples. [Copyright &y& Elsevier]

Abstract: ZnO films were deposited on c-plane Al2O3 substrates by pulsed laser deposition. The etching treatments for as-grown ZnO films were performed in NH4Cl aqueous solution as a function of NH4Cl concentration and etching time. It was found that NH4Cl solution is an appropriate candidate for ZnO wet etching because of its controllable and moderate etching rate. The influence of etching treatment on the morphology, optical and electrical properties of the ZnO films has been investigated systematically by means of X-ray diffraction, atomic force microscope, photoluminescence and Hall effect. The results indicated that the surface morphology and optical properties of the films were highly influenced by etching treatment. [Copyright &y& Elsevier]