| In 2000, scientists S. Q. Liu et al at the University of Houston found the reversible resistance switching effect induced by electrical impulses. They proposed the concept of RRAM (Resistance Random Access Memory). They also found RRAM with the high response speed, size strong scalability, a number of storage, simple structure. Since then, study of materials science and electronics device focus on RRAM field. People have made great progresses in the mechanism of the resistance switching, and the materal exporation and the development of resistance switching devices. RRAM devices may become a brand-new memory device, but performance indicators need be further optimized. RRAM possiblely become a new storage technology, but the real mechanism of resistance switching effect is controversial currently. Since the mechanism is not clear, the resistance-switching memory device is not put in use. The elements of chemical changes, the positions of the resistance change and the repeatability in the rensitance switching aren't known ,this is the current critical issues of the RRAM device facing. Meanwhile, the performance of materals, the preparation of materals to meet the requirements is still the key to the development of RRAM devices.The candidate materials of the resistance random access memory are binary oxides with a simple structure, multiple perovskite oxides with complex composition, organic compounds. Undoubtedly the semiconductor materials of binary transition metal oxide are the most potential materals. The main researche topics focus on titanium dioxide, zinc oxide, nickel oxide, zirconia, copper oxide, cerim oxide and so on. The unit of storages is similar to the simple sandwich structure of capacitors that the metal electrode is in the both sides of the insulating or semiconduct material. This resistance switching phenomena exhibit very rapid switching speeds and huge off ratioes, this is of great scientific value and significance and broad prospects for the application development of the RRAM.Zinc oxide (ZnO) is semiconductor materials of wide band gap compound with a direct band gap, which is 3. 37 eV band gap . The exciton binding energy is 60 meV with the high thermal stability . ZnO have excellent optical properties at room temperature. Recent studies have found that ZnO doped by transition metals can reduce the intrinsic carrier concentration and produce deep level. For example, the resisstance of the high resistance state of Mn-doped ZnO become larger at room temperature than ZnO, thus helping to increase the ratio of the high resistance and low resistance. The Cu-doped ZnO can be used to control not only the thin film resistors, but also it showed p-type conductivity. Cu-doped ZnO materal is a classic diluted magnetic semiconductor at room temperature and a promising multi-functional material in applications. As far as we know, no paper of ZnO: Cu resistance switching has been reported recently . Therefore the ZnO: Cu film had been selected as the resistance switching materials in my study.1. 20 gram of ZnO and CuO powder was weighed with the balance according to molar ratios of 1 to 99, 5 to 95, and 9 to 91 respectively. After several steps, so I prepared three Cu-doped ZnO ceramic targets finally.2. By the pulsed laser deposition (PLD) ZnO and ZnO: Cu films were deposited on the Si, quartz, platinum substrate . by the X-ray diffraction(XRD), the photoluminescence(PL), the Raman spectroscopy(Raman), the X-ray photoelectron spectroscopy (XPS), the atomic force microscope (AFM), the samples prepared were characterized. The results show that the thin films crystallized perfectly by the pulsed laser deposition (PLD) technology.3. The ZnO: Cu films were successfully prepared by the pulsed laser deposition technique on FTO conducting glasses and Pt/SiO2/Si substrates. By the Keithley 2400, the electrical characteristics of the Au / ZnO: Cu / FTO sandwich structure were studied. Significant effects of the resistance switching characteristic were observed and possible conduction mechanisms were discussed.
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