Preparation And Optical Properties Of Mg_xZn_1-xO Optical Thin Films

ZnO with a wide band gap and a large excitation binding energy at room temperature, has excellent optoelectronic characteristics. It has been considered as one of the most important optoelectronic materials. In order to prepare ZnO-based alloy materials which have a wider bandgap, one kind of bigger energy gap material needs to be seeked to mix into ZnO crystal matrix and realizes its band gap adjustment. The band gap of MgxZn1-xO alloy thin films can be tuned from3.37eV to7.8eV as a result of the Mg incorporation into ZnO films. So MgxZn1-xO alloy thin film as II-VI wide band gap semiconductor alloy material has been the research hotspot in recent years.MgxZn1-xO thin films with different substrate temperatures and Mg doping concentration were prepared by atom layer deposition (ALD) and were annealed at different temperatures. The optical properties and crystal structure of the samples were characterized by X-ray diffraction (XRD), photoluminescence (PL), ultraviolet-visible (UV-vis) absorption spectra, and field emission scanning electron microscopy (FESEM). The results showed that, the UV emission intensity and crystal quality of MgxZn1-xO thin films were relatively optimum when the substrate temperature was170℃, MgxZn1-xO thin films with controllable components and optical band gap can be obtained by different Mg doping concentration, and suitable annealing temperature can effectively improve the crystal quality and optical properties of MgxZn1-xO thin films. ALD technology has good conformality. Band gap and UV emission intensity of ZnO nanofibers were improved by Mg doping. Thus doped nanofibers could be used in ultraviolet photonic devices, sensors and other nanodevices.