本文選題：ZnMgO薄膜　切入點(diǎn)：氧空位　出處：《山西師范大學(xué)》2015年碩士論文

【摘要】：稀磁半導(dǎo)體材料由于其在未來(lái)半導(dǎo)體自旋電子學(xué)器件中的巨大潛在應(yīng)用而受到人們的廣泛關(guān)注。近幾年，3d過(guò)渡金屬元素?fù)诫s的具有室溫鐵磁性的寬禁帶氧化物半導(dǎo)體材料取得了很大進(jìn)展，但其磁性來(lái)源卻一直存在較大爭(zhēng)議。最近，非磁性元素?fù)诫s或無(wú)摻雜氧化物薄膜的d0鐵磁性引起人們的研究興趣，在這類(lèi)材料中，不需要考慮第二相磁性雜質(zhì)對(duì)材料磁性的貢獻(xiàn)，可以更好地研究材料缺陷等因素對(duì)氧化物薄膜磁性的影響。本論文利用脈沖激光沉積系統(tǒng)，在不同的沉積條件下制備出了多個(gè)系列的ZnMgO薄膜樣品，研究了沉積氧壓及靶材中Mg含量的改變對(duì)薄膜結(jié)構(gòu)、磁性及光學(xué)帶隙的影響；并在相同沉積氧壓下探究了ZnMgO薄膜中氧空位、磁性與帶隙間的關(guān)系；另外還研究了不同沉積氧壓下制備的ZnMgCoO薄膜，，分析了沉積氧壓對(duì)薄膜結(jié)構(gòu)、磁學(xué)及光學(xué)性質(zhì)的影響。主要研究?jī)?nèi)容如下： （1）我們選用脈沖激光沉積系統(tǒng)，在雙拋Al2O3(0001)基片上制備了一系列沉積氧壓遞變的Zn0.9Mg0.1O薄膜，發(fā)現(xiàn)隨沉積氧壓的增大，薄膜沿c軸方向的晶格常數(shù)不斷減小，對(duì)應(yīng)的ZnO（002）峰逐漸向右偏移；而薄膜的帶隙則隨著沉積氧壓的增大而減小，這是由于薄膜中的Mg含量與沉積氧壓成反比；Zn0.9Mg0.1O薄膜材料的室溫飽和磁化強(qiáng)度則呈現(xiàn)出一種先增大后減小的趨勢(shì)，這可能與氧空位的濃度變化有關(guān)，本底真空生長(zhǎng)的薄膜中缺陷種類(lèi)較多，使得氧空位的有效濃度降低，影響了材料的磁性，在沉積氧壓增加的過(guò)程中，氧空位濃度會(huì)出現(xiàn)一個(gè)最大值，然后逐漸減小。我們?cè)谙嗤闹苽錀l件下沉積了一系列Zn0.85Mg0.15O薄膜，并得到了與上述變化規(guī)律一致的實(shí)驗(yàn)結(jié)果。此外，我們還選用Zn0.9Mg0.1O合金陶瓷靶材，在完全相同的沉積氧壓下制備了一系列Zn0.9Mg0.1O薄膜材料，研究發(fā)現(xiàn)氧空位可以起到同時(shí)調(diào)控薄膜磁性及光學(xué)帶隙的作用。薄膜中氧空位濃度越大，磁性越強(qiáng)，光學(xué)帶隙越窄。 （2）我們選用純ZnO陶瓷靶材以及由固相反應(yīng)法制得的Zn0.95Mg0.05O、Zn0.9Mg0.1O和Zn0.85Mg0.15O合金陶瓷靶材，分別在本底真空和20mTorr氧壓下，以雙拋Al2O3(0001)基片為襯底制備了多種Zn1-XMgXO薄膜樣品，發(fā)現(xiàn)隨靶材中Mg含量的增加，薄膜ZnO(002)峰對(duì)應(yīng)的2θ值不斷增大，這是由于Mg2+半徑小于Zn2+半徑所致；由于MgO的帶隙遠(yuǎn)大于ZnO的帶隙，薄膜中的Mg含量越高，薄膜的帶隙也越大；然而，隨Mg摩爾百分比（X）的增加，Zn1-XMgXO薄膜的室溫飽和磁化強(qiáng)度呈現(xiàn)出先升高后降低的趨勢(shì)，且在X=0.10時(shí)達(dá)到最大，導(dǎo)致這種變化規(guī)律的原因可能是由于Mg的加入使ZnO晶體中出現(xiàn)更多與室溫鐵磁性相關(guān)的點(diǎn)缺陷，而當(dāng)Mg的含量過(guò)多時(shí)，ZnO晶體中的缺陷種類(lèi)繁復(fù)，以致有效缺陷濃度降低所致。 （3）選用脈沖激光沉積技術(shù)以雙拋Al2O3(0001)基片為襯底，在不同的沉積氧壓下制備了過(guò)渡金屬Co摻雜的Zn0.85Mg0.10Co0.05O薄膜，發(fā)現(xiàn)隨沉積氧壓的增大，薄膜ZnO（002）峰逐漸向右偏移，帶隙逐漸減小，室溫鐵磁性先升高后減低，與Zn0.9Mg0.1O和Zn0.85Mg0.15O薄膜的變化規(guī)律相同。
[Abstract]:In recent years , it is not necessary to consider the contribution of the second - phase magnetic impurities to the magnetic properties of oxide films .
The relationship between oxygen vacancy , magnetic and gap in ZnMgO thin films was investigated under the same oxygen pressure .
The effects of deposition oxygen pressure on film structure , magnetic properties and optical properties were studied . The main research contents were as follows :

( 1 ) We chose a pulsed laser deposition system to prepare a series of Zn0.9Mg0 . 1O films deposited with oxygen pressure on a double - cast Al2O3 ( 0001 ) substrate . It was found that the lattice constant of the film in the direction of the c - axis decreased with the increase of the deposition oxygen pressure , and the corresponding ZnO ( 002 ) peak shifted to the right ;
The band gap of the film decreases with the increase of the deposition oxygen pressure , because the Mg content in the film is inversely proportional to the deposition oxygen pressure ;
A series of Zn0 . 85Mg0 . 15O films were deposited under the same conditions .

( 2 ) We chose pure ZnO ceramic target and Zn0 . 95Mg0 . 05O , Zn0 . 9Mg0 . 1O and Zn0 . 85Mg0 . 15O alloy ceramic target prepared by solid phase reaction .
As the band gap of MgO is much larger than that of ZnO , the higher the Mg content in the film , the larger the band gap of the film .
However , with the increase of Mg mole percentage ( X ) , the room temperature saturation magnetization of the Zn1 - XMgXO thin film exhibits a tendency to decrease first and reach the maximum at X = 0.10 , which may cause more point defects in the ZnO crystal due to the addition of Mg , and when the content of Mg is too much , the type of defects in the ZnO crystal is complex , so that the effective defect concentration is reduced .

( 3 ) The Zn0 . 85Mg0 . 10Co0 . 05O films doped with the transition metal Co were prepared by pulsed laser deposition . The ZnO ( 002 ) peak was shifted to the right with increasing oxygen pressure , the band gap was gradually decreased , the room temperature ferromagnetism increased first and then decreased , which was the same as that of Zn0 . 9Mg0 . 1O and Zn0 . 85Mg0 . 15O films .

【學(xué)位授予單位】：山西師范大學(xué)
【學(xué)位級(jí)別】：碩士
【學(xué)位授予年份】：2015
【分類(lèi)號(hào)】：O649;TB383.2

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本文編號(hào)：1695151