本文選題：稀磁半導(dǎo)體 + 磁控濺射��； 參考：《西北師范大學(xué)》2015年碩士論文

【摘要】：ZnO作為一種性能優(yōu)良的寬帶隙半導(dǎo)體材料,具有較高居里溫度以及室溫鐵磁性而成為制備稀磁半導(dǎo)體的重要材料之一,因過渡金屬摻雜的Zn O基稀磁半導(dǎo)體材料同時具備電子的電荷特性和自旋特性,使其在自旋電子學(xué)和光電子領(lǐng)域具有廣泛應(yīng)用前景。利用其電學(xué)性質(zhì)可制作高速緩沖存儲器;利用其磁學(xué)性質(zhì)可制作出永久性信息存儲器,使其有望成為新一代信息存儲的載體。本論文利用磁控濺射制備了Fe摻雜ZnO半導(dǎo)體樣品,研究了Fe的摻雜量、退火溫度、退火氣氛對樣品的微結(jié)構(gòu)和室溫鐵磁性的影響,將納米薄膜的微結(jié)構(gòu)缺陷和鐵磁性聯(lián)系起來,對Fe摻雜ZnO納米薄膜室溫鐵磁性的來源進(jìn)行了解釋。1.采用磁控濺射法在Si襯底上制備了純ZnO和Zn1-xFexO(x=1.0%,3.0%,5.0%,7.0%)納米薄膜,分別在真空和空氣中用不同溫度對樣品進(jìn)行退火處理后得到Fe摻雜ZnO稀磁半導(dǎo)體納米薄膜材料。利用X光衍射儀(XRD)、掃描電子顯微鏡(SEM)、能譜儀(EDS)、以及X射線光電子能譜儀(XPS)和振動樣品磁強(qiáng)計(VSM)對樣品的微結(jié)構(gòu)、表面形貌、元素成分、元素化學(xué)價態(tài)和室溫鐵磁特性進(jìn)行測試。2.XRD測試結(jié)果表明,樣品均為六角纖鋅礦結(jié)構(gòu),沿c軸擇優(yōu)生長,Fe摻雜量和退火溫度對薄膜微結(jié)構(gòu)有一定程度的影響,隨著Fe摻雜量的增加,樣品的衍射峰強(qiáng)度先增大后減小,薄膜中的應(yīng)力逐漸增大,晶粒尺寸逐漸減小;當(dāng)退火溫度為450oC時,出現(xiàn)了最強(qiáng)的(002)衍射峰,晶粒大小變?yōu)樽畲?薄膜的結(jié)晶度和取向性都明顯變好,之后隨著退火溫度的上升薄膜晶粒變小,衍射峰強(qiáng)明顯變?nèi)酢＠肧EM對樣品表面形貌和斷面觀測結(jié)果表明,Fe的摻雜能提高ZnO:Fe納米薄膜的晶粒均勻性和表面致密性;隨著退火溫度的升高,薄膜表面平整性逐漸改善,晶粒變大,但大小仍不均勻。薄膜厚度隨著摻雜濃度的增大先增加后減小,退火溫度和氣氛對薄膜的生長有一定的影響,空氣中450℃溫度退火時薄膜平均厚度為最大。通過對其EDS譜的分析,確定我們成功將Fe摻入ZnO納米薄膜中,并且XPS分析發(fā)現(xiàn)Fe在薄膜中以Fe2+和Fe3+兩種價態(tài)存在。3.利用VSM對薄膜的鐵磁性進(jìn)行了測量,結(jié)果表明所有樣品均出現(xiàn)一條S形的完整的磁滯回線,說明具有較明顯的室溫鐵磁性。Fe元素的摻雜量、退火溫度、退火氣氛均對薄膜鐵磁性有一定程度的影響。隨著Fe元素的摻雜量增加,薄膜飽和磁化強(qiáng)度逐漸減小,但仍大于純Zn O薄膜的飽和磁化強(qiáng)度;隨著退火溫度的上升,薄膜磁化強(qiáng)度有逐漸增大的趨勢;空氣中退火的樣品磁化強(qiáng)度均小于純ZnO薄膜的磁化強(qiáng)度。對其鐵磁性用缺陷與周圍的磁性離子形成的束縛磁極化子(BMP)理論進(jìn)行了解釋。
[Abstract]:As a kind of wide band gap semiconductor material with excellent properties, ZnO is one of the important materials for preparing dilute magnetic semiconductors due to its high Curie temperature and ferromagnetism at room temperature. ZnO-based diluted magnetic semiconductors doped with transition metals have both charge and spin properties of electrons, which makes them widely used in the fields of spin electronics and optoelectronics. Cache memory can be made by using its electrical property, and permanent information memory can be made by using its magnetic property, which is expected to become the carrier of the new generation of information storage. In this paper, Fe doped ZnO semiconductor samples were prepared by magnetron sputtering. The effects of Fe doping amount, annealing temperature and annealing atmosphere on the microstructure and room temperature ferromagnetism of the samples were studied. The source of room temperature ferromagnetism of Fe doped ZnO nanocrystalline films was explained. Pure ZnO and Zn1-xFexOX1.0 nanocrystalline films were prepared on Si substrates by magnetron sputtering. Fe doped ZnO thin films were prepared by annealing in vacuum and air at different temperatures. The microstructure, surface morphology and elemental composition of the samples were characterized by X-ray diffractometer, scanning electron microscope (SEM), energy spectrometer (EDS), X-ray photoelectron spectroscopy (XPS) and vibrating sample magnetometer (VSM). The chemical valence state of elements and ferromagnetic properties at room temperature were measured. 2. The results of XRD showed that the samples were hexagonal wurtzite structure, and the doping amount of Fe and annealing temperature along the c-axis had some influence on the microstructure of the films. With the increase of Fe doping content, the diffraction peak intensity of the sample first increases and then decreases, the stress in the film increases gradually, the grain size decreases gradually, and the strongest diffraction peak appears when the annealing temperature is 450oC, and the grain size becomes the largest. The crystallinity and orientation of the films improved obviously, and the diffraction peak strength became weaker with the increase of annealing temperature. The results of surface morphology and cross section observation by SEM show that the doping of Fe can improve the grain uniformity and surface compactness of ZnO:Fe nanocrystalline films, and with the increase of annealing temperature, the surface smoothness and grain size of the films are improved gradually. But the size is still uneven. The thickness of the films increases first and then decreases with the increase of doping concentration. Annealing temperature and atmosphere have a certain influence on the growth of the films. The average thickness of the films annealed at 450 鈩，

本文編號：1944760