Effect Of Different Substrates And Temperatures On The Properties Of ZnCdO Films Prepared By Electron Beam Evaporation

ZnO, with a wide bandgap (3.37eV) at room temperature and larger exciton binding energy (60meV), is a II-VI compound semiconductor material, and has wide application prospects in optoelectronic devices such as short-wavelength laser diodes and ultraviolet photodetectors. And the most important method of realizing these devices is to modulate the band gap of ZnO. According to the corresponding research, by doping certain Cd component into ZnO, Zn1-xCdxO alloy semiconductors have been prepared, and the luminescent wavelength spectrum of which can be shifted in the range from the ultra-violet light to blue-green light.In this paper, a series of ZnO:Cd films have been deposited on sapphire, Si(111), and quartz substrates, respectively, using electron beam evaporation method by evaporating the fixed component of the ZnO/CdO (molar ratio95:5) ceramic target. X-ray diffraction (XRD), field-emission scanning electron microscopy (FESEM), photoluminescence (PL) spectrum (the He-Cd laser is used as the laser source with the wavelength of325nm), transmission spectrum and Hall effect etc. were utilized to investigate the structure, morphology, optical and electric properties of the ZnCdO films. The main research results are summarized as the follows:Firstly, a series of ZnCdO films were prepared on sapphire substrates at different substrate temperature by the electron beam evaporation method. The results show that the films with highly preferred orientation of c-axis were highly affected by the substrate temperature. As the substrate temperature increased, the intensity of (002) diffraction peak increased gradually, and the FWHM decreased gradually. The optimal ZnCdO film was obtained at the temperature of500℃. In addition, dense nanowires were formed on the morphology with a prominent UV emission band. The transmittance is up to more than90%and a minimum resistivity was obtained.Secondly, the films prepared at300℃were annealed at different temperatures. According to the XRD results, high-quality film with the highest diffraction peak was acquired at the annealing temperature of550℃.Finally, a series of ZnCdO films were grown on sapphire, Si(111), and quartz substrates, respectively by the electron beam evaporation method. The results show that the change tendency of structure, morphology and optoelectronic characteristics was accordant, and the influence of the substrate could be ignored. Moreover, the crystallization quality of the film grown on different substrates was getting better and better in the order of quartz, Si(111) and sapphire.