Structural And Magnetic Studies Of Cu, Ag-doped ZnO Thin Films

Zinc oxide (ZnO) is one kind of the semiconductor materials that has the characteristicsof piezoelectric and photoelectric, it can be used to solar cells, piezoelectric membrane,optical devices, etc. In2000, Dietl use the Zener model calculat Mn doped ZnO and Mndoped GaN that presume magnetic semiconductor will have room temperature ferromagnetic(RTFM) with the broadband gap semiconductor microspheres rare.Thus, research boom ofZnO was raised.In my paper, dc sputtering method was used in the preparation of Cu, Agseries doped ZnO thin films with adjusted experiment conditions, the morphologies, crystalstructure and magnetic properties were studied.1. Cu doped ZnO films were prepared on glass substrates by DC magnetron sputteringwith the different sputtering power to control the amount of Cu doping. Different content ofCu-doped ZnO thin films were preapared by different power on Cu. and then all the samplesof films were annealed in the vacuum and air. Because the magnetic metal doped ZnO thinfilm magnetic signal is weak, with the right magnetic correction method, accurate deduct basesignal is very necessary. Therefore this paper used a new correction method for magneticmeasurement results, calculated the maximum error of the glass substrates, and analyzed themagnetic of the sample after correction. The results show that: RT ferromagnetism wasobserved in these films and saturation magnetic moment decreases with Cu concentrationincreasing. The origin of ferromagnetism comes from Cu replace the position of Zn.2. ZnO films were prepared on different substrates as glass substrates, Si and sapphire.The Zno films deposited at200℃unchanged and the samples of films were annealed in thevacuum for30min. The experimental results show that: the types of the substrates have verybig effect about crystal structure, morphology and magnetic of films. The stress of the Sisubstrate preparation sample film is the largest and coercive force is the most.3. Ag doped ZnO films were prepared on glass substrates by DC magnetronsputtering.change the amount of Ag doping, and studied their morphologies, crystal structureand magnetic properties. The results show that: RT ferromagnetism was observed in these Agdoped ZnO films. In addition, because the surface activity of Ag is very strong, so sample films have very strong timeliness. Sample placed after a month, then proceeding with twotime’s magnetic measurement: before and after. Compare Measurement results show that:Sample placed after a month, magnetic significantly weakened. The results prove that the Agdoped ZnO thin film of room temperature ferromagnetic comes from Ag replace the positionof Zn.