Mg-doped Nano-ZnO Via Chemical Vapor Deposition And Resistive Switching Effect

The development of nanotechnology allows us to fabricate a series of compound semiconductor materials. Zinc oxide,Ⅱ-Ⅵcompound semiconductor, has attacted more and more attentions due to the potential applications for electro-optica devices. It is a direct band gap material with a 3.37 eV band gap. At room temperature, ZnO has a large exciton binding energy about 60meV. Similar to ZnO, MgO is also outstanding electro-optical properties. The MgO band gap approximately is 7.7 eV. By doping Mg element into ZnO, the band gap of ZnO may be modulated. This causes more obvious advantages in the photoelectric device applications.1,In this work, Mg-doped ZnO nanomaterials have been prepared through chemical vapor deposition (CVD), by adjusting experiment parameter and using different substrate. The appearance, components, growth mechanism, optical properties and the electrical natures of the samples have been studied by various devices (SEM, EDS, XRD, PL spectrum and the I-V sweeping). Mg-doped ZnO radial spherical nanorods have been prepared on Si(P-type 100) substrate without any impurity. The nanorods has been grown on both sides of spherical shell which presents high crystallinity with hexagon structure. This is an autocatalysis growth way. The photoluminescence (PL) spectra shows a 39 meV blue shift which indicates the band gap become large, because Mg substitute Zn in the lattice.2,Matchstick shape Mg_xZn_1-xO nanowire and injector shape Mg_xZn_1-xO nanowire have been prepared on Pt/TiO₂/SiO₂/Si (P-type 100) substrate. The SEM and XRD spectrum indicate their hexagon structure. Matchstick shape Mg_xZn_1-xO nanowire become more and more coarse in growth process. By analyzing their growth mechanism, the key of formation of Pt-Zn alloys is the substrate temperature. The presence of four peaks of nanowire's PL spectra are located at 363 nm, 395 nm, 424 nm, 485 nm position, which corresponds respectively to UV, near UV, blue and blue-green light.3,The samples grown on Pt/TiO₂/SiO₂/Si substrate coated Pt electrode, tested the I-V curve which showed the resistive switching effect. Nanowires show the bipolar resistance switching, but the RH /RL is very small, The samples of film show the unipolar resistive switching, whose RH /RL is 50 times. In addition, the VReset and VSet is not too large. Analysing the tansforming mechanism between LRS and HRS, the tansforming mechanism is mainly conductive filaments in the low resistance state (LRS), the tansforming mechanism is the space charge limited current (SCLC ) effect in the high resistance state (HRS).