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Doped ZnO thin film magnetic materials Preparation and magnetic properties at room temperature

Author: WangYingLei
Tutor: ChenXiMing
School: Tianjin University of Technology
Course: Microelectronics and Solid State Electronics
Keywords: Diluted magnetic semiconductor ZnO Magnetron sputtering Sol-gel method Ferromagnetism
CLC: O484.1
Type: Master's thesis
Year: 2010
Downloads: 87
Quote: 0
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Abstract


Diluted magnetic semiconductors (DMS) materials available electron spin energy required is small, easy to control, etc. to achieve many of the new multi-function devices. Among them, wurtzite ZnO Due to the growth temperature is low, a larger exciton binding energy (60meV), wide band gap (3.27eV) support larger magnetic doping concentration is predicted to achieve a high Curie temperature etc., a study of II-VI DMS ideal. This paper first describes the current awareness of relevant research dilute magnetic semiconductors, ZnO-based DMS focuses on research. Looking for a better preparation of doped ZnO diluted magnetic materials technology program, we stratified by magnetron sputtering and co-sputtering prepared Cr-doped ZnO films and sol - gel method (sol-gel) was prepared Fe-doped ZnO films. The structure of thin films, composition and magnetic properties. 1 Preparation of (1) using stratified magnetron sputtering target to Cr and ZnO, prepared with different concentrations of Cr-doped ZnO films. ZnO target RF sputtering power of about 175W, DC sputtering Cr target power is about 165W, by changing each of sputtering time (10s-30s) to change the doping concentration. Tested analysis of sputtering time of each 20s, that is doped with a concentration of 2%, the substrate is a silicon crystal samples of the best, but the sample substrate is ferromagnetic slide strongest. (2) by co-sputtering targets to Cr and ZnO, prepared with different concentrations of Cr-doped ZnO films. By fixed RF sputtering ZnO target power of about 175W, change the DC sputtering Cr target power from 10W to 48W, to change the doping concentration. Tested analysis Cr target DC power of 24w, i.e. when the doping concentration of 2%, the crystallinity the best, but the DC power of the Cr target 10w, i.e. doping concentration of 1% of the samples for the strongest magnetic iron. (3) using zinc acetate dihydrate with FeCl 2 .4 H 2 O as the precursor, ethylene glycol monomethyl ether as solvent, ethanolamine as a stabilizer, with the sol-gel Preparation of Fe-doped ZnO films. Tested analysis substrate is silicon, thin-film crystal pulling better prepared. (2) Magnetic temperature (1) and slide silicon substrate respectively, layered sputtering is 2% of Cr doped, slide better magnetic properties of the sample, the lattice constants of the substrate and ZnO may close to varying degrees, resulting in the same process, the films of different microstructures, different distributions of dopant ions, thus affecting the magnetic properties different to room temperature. (2) substrates are glass slides, were 2% Cr doped with stratified sample of magnetic sputtering sputtering ratio of magnetic samples prepared better. This may be due to sputtering of a more uniform doping some samples, the score layer deposition sputtering power is smaller, eventually resulting in the films of different samples and defect structure will affect its magnetic properties different temperature. (3) analysis Cr: ZnO doped systems ferromagnetism comes from its essential attributes, namely ferromagnetic exchange and antiferromagnetic exchange interactions competition.

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CLC: > Mathematical sciences and chemical > Physics > Solid State Physics > Thin Film Physics > Film growth,structure and epitaxy
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