本文主要研究内容
作者谢继浩（2019）在《电场和光对氧化物薄膜磁性调控的研究》一文中研究指出：薄膜材料作为新材料的重要组成部分,在现代社会中发挥着重要作用。薄膜材料有其独特的优势,是器件小型化的基础,它可以制成具有多种特性的复合薄膜材料,避免单一性能薄膜材料的局限性。氧化物薄膜是薄膜材料的一个重要组成,被广泛应用于先进功能材料、存储器件、计算机、环保、生物医学等诸多领域。许多薄膜材料都具有磁性,薄膜结构的复杂多变也导致其磁性来源多种多样。人们已经发现通过调控薄膜材料的磁性可以实现信息的读写与存储。经过不断地探索,人们发现电场、光、电流、应力和掺杂等方式都可以调控薄膜材料的磁性。其中,电场和光是两种备受青睐的磁性调控方式,它们具有低功耗、可逆性、速度快和良好的兼容性等诸多优势。到目前为止,人们已经对电场调控磁性和光调控磁性有了一定的认识,并且在器件实际应用中也取得了很大进展。现代电子信息技术的发展和智能设备的普及使得信息数据量呈几何式增长,人们迫切想要获得更快速度更高密度的存储设备。阻变随机存储器(Resistive Random Access Memory,RRAM)在该背景下应运而生,它具有高密度、操作快速和多值存储等优点。更为重要的是,阻变现象的部分机理与所使用的氧化物薄膜的磁性来源有所重叠,这使得器件呈现出电阻转变和磁性调控共存的现象,从而使器件可以获得更多用于存储的状态。与此同时,氧化物材料对光的响应使得器件的阻变效应发生改变,在很大程度上可以提升器件性能。基于氧化物薄膜的阻变存储器结合电场和光能够实现光、电、磁三者之间的相互作用,可以发现更多具有优异性能的材料组合,为实现微小型多功能器件提供机遇。本论文探究了电场和光对几种氧化物薄膜磁性的调控,其主要内容如下:(1)我们使用射频磁控溅射技术制备了 ZnO薄膜,该薄膜具有室温铁磁性,其磁性来源是氧空位。随后制备成的ITO/ZnO/Pt器件具有双极性阻变,其阻变机理是电场调节的氧空位导电细丝的形成与断裂。该器件的阻变效应也受紫外光的影响,表现在器件电流的增大和设置电压的减小。这个现象是由光照时ZnO表面氧的解吸附所导致的。ITO/ZnO/Pt器件在高低阻态时的磁性也不相同,低阻态时器件的磁性高于高阻态时的磁性,其原因是低电阻态时ZnO薄膜内氧空位含量更高。光照可以使器件高低阻态的磁性都增强,这个现象与光照后氧空位类型的转变有关。ZnO薄膜表现出的阻变效应及磁性转变可能在多态存储领域发挥一定的应用。(2)通过对光致发光光谱的研究,我们证实ZnO薄膜的室温铁磁性来源于单电离氧空位(Vo+)。Pt/Ti/SiO2/Si衬底上ZnO的磁性在紫外光和紫光的照射下会增强。其主要原因是光生电子被双电离氧空位(Vo++)捕获所导致的单电离氧空位(Vo+)增多。MgO衬底上ZnO磁性调控的对比结果显示内建电场在该过程中起到了重要作用。光对ZnO磁性的改变需要一段时间才能恢复,这与ZnO薄膜表面氧分子的再吸附有关。非偏振光在室温条件下调控ZnO的磁性可能在光磁耦合器件中具有一定潜在的应用。(3)我们使用射频磁控溅射技术制备了 TiO2薄膜,生长在Ag/Ti/Si02/Si和Pt/Ti/SiO2/Si衬底上的TiO2薄膜具有室温铁磁性,并且单电离氧空位(Vo+)被认为是其磁性的来源。两种衬底上TiO2薄膜的磁性都可以被紫光所调控,并且Ag衬底上薄膜的磁性还可以被蓝光所调控,我们认为Ag金属颗粒的局域表面等离激元效应是该现象产生的原因。我们通过EDS测试发现Ag扩散进入薄膜要比Pt多一些。同时,Ag对TiO2的光吸收也产生了影响,使其可吸收的可见光范围增大。Ag金属颗粒的局域表面等离激元效应会导致表面增强拉曼散射,测试结果显示Ag衬底上TiO2的拉曼峰明显增强。Ag金属颗粒的局域表面等离激元效应使得TiO2薄膜可以吸收部分蓝光,从而使自身磁性发生改变。(4)我们在Pt/Ti/SiO2/Si衬底上生长的CuxO薄膜具有室温铁磁性,实验研究发现其磁性来源可能是间接双交换作用(Cu+-Vo-Cu2+)和一部分氧空位。CuxO薄膜磁性在光照下会发生改变,并且频率高的光对磁性影响更大。通过光照对不同衬底上CuxO薄膜磁性影响的实验,可以发现界面处形成的内建电场对磁性变化起重要作用,它可以有效地分离光生电子-空穴对。光生空穴和电子在迁移过程中的俘获可能导致Cu离子在局部区域的价态转变,形成更多的Cu+-Vo-Cu2+,并增强铁磁性。部分不参与间接双交换作用的氧空位也可能捕获少量光生电子,对磁性产生影响。我们发现Ag/CuxO/Nb:SrTi03/Ag器件具有特殊的阻变效应,其电流-电压曲线存在明显的整流特性。该器件在电阻变化时伴随稳定的磁性变化。器件的电阻转变来源于电场作用下氧空位迁移引起的界面处类肖特基势垒高度的变化。间接双交换作用(Cu+-Vo-Cu2+)可以用来解释CuxO薄膜的磁性,氧空位在该间接交换中起媒介作用。不同电场下,界面势垒高度不相同,从而器件电阻状态不相同,而决定界面势垒高度的氧空位又直接影响磁性,导致了不同电阻态下磁性大小也不同。Ag/CuxO/Nb:SrTiO3/Ag器件磁性在室温下也可以被光所调控。其原因可能是光生空穴或电子的捕获,导致局部Cu离子化合价的转变,进而影响间接双交换作用。(5)我们制备的Ta/La2/3Sr1/3MnO3/Nb:SrTiO3/Ag器件同时具有阻变效应和磁性调控。该器件的阻变效应受施加电场时氧离子的迁移和界面类肖特基势垒的共同影响。在不同的电场下,氧离子的迁移方向是不同的,正向电场会使氧离子迁移后在薄膜中留下氧空位,氧空位的增多会逐渐形成氧空位导电细丝或导电区域,贯穿界面类肖特基势垒区域,使器件进入低阻态。施加负向电场时,氧离子回填氧空位,导电细丝或导电区域断裂,界面势垒恢复到原先状态,器件重回高阻态。器件的阻变效应也伴随磁性变化,器件在高低阻态时的磁性大小也不相同,其原因是氧离子的迁移影响了双交换作用。La2/3Sr1/3MnO3/Nb:SrTiO3的磁性在70K可以被光所调控,主要原因可能是光生电子改变了费米面上的电子轨道占据,影响了薄膜磁各向异性,进而改变了薄膜的矫顽力。我们探究的几种氧化物薄膜的磁性来源主要是氧空位、氧空位介导的间接双交换作用和双交换作用,其中前两种类型磁性相对较弱,第三种类型磁性相对较强。电场是一个强的外场,可以在室温下直接改变材料的磁性,而光是一种相对较弱的外场,室温时只能改变较弱的磁性,低温时才能改变较强的磁性。我们对氧化物薄膜磁性调控的研究可能对实际器件的应用有一定的帮助。
Abstract
bao mo cai liao zuo wei xin cai liao de chong yao zu cheng bu fen ,zai xian dai she hui zhong fa hui zhao chong yao zuo yong 。bao mo cai liao you ji du te de you shi ,shi qi jian xiao xing hua de ji chu ,ta ke yi zhi cheng ju you duo chong te xing de fu ge bao mo cai liao ,bi mian chan yi xing neng bao mo cai liao de ju xian xing 。yang hua wu bao mo shi bao mo cai liao de yi ge chong yao zu cheng ,bei an fan ying yong yu xian jin gong neng cai liao 、cun chu qi jian 、ji suan ji 、huan bao 、sheng wu yi xue deng zhu duo ling yu 。hu duo bao mo cai liao dou ju you ci xing ,bao mo jie gou de fu za duo bian ye dao zhi ji ci xing lai yuan duo chong duo yang 。ren men yi jing fa xian tong guo diao kong bao mo cai liao de ci xing ke yi shi xian xin xi de dou xie yu cun chu 。jing guo bu duan de tan suo ,ren men fa xian dian chang 、guang 、dian liu 、ying li he can za deng fang shi dou ke yi diao kong bao mo cai liao de ci xing 。ji zhong ,dian chang he guang shi liang chong bei shou qing lai de ci xing diao kong fang shi ,ta men ju you di gong hao 、ke ni xing 、su du kuai he liang hao de jian rong xing deng zhu duo you shi 。dao mu qian wei zhi ,ren men yi jing dui dian chang diao kong ci xing he guang diao kong ci xing you le yi ding de ren shi ,bing ju zai qi jian shi ji ying yong zhong ye qu de le hen da jin zhan 。xian dai dian zi xin xi ji shu de fa zhan he zhi neng she bei de pu ji shi de xin xi shu ju liang cheng ji he shi zeng chang ,ren men pai qie xiang yao huo de geng kuai su du geng gao mi du de cun chu she bei 。zu bian sui ji cun chu qi (Resistive Random Access Memory,RRAM)zai gai bei jing xia ying yun er sheng ,ta ju you gao mi du 、cao zuo kuai su he duo zhi cun chu deng you dian 。geng wei chong yao de shi ,zu bian xian xiang de bu fen ji li yu suo shi yong de yang hua wu bao mo de ci xing lai yuan you suo chong die ,zhe shi de qi jian cheng xian chu dian zu zhuai bian he ci xing diao kong gong cun de xian xiang ,cong er shi qi jian ke yi huo de geng duo yong yu cun chu de zhuang tai 。yu ci tong shi ,yang hua wu cai liao dui guang de xiang ying shi de qi jian de zu bian xiao ying fa sheng gai bian ,zai hen da cheng du shang ke yi di sheng qi jian xing neng 。ji yu yang hua wu bao mo de zu bian cun chu qi jie ge dian chang he guang neng gou shi xian guang 、dian 、ci san zhe zhi jian de xiang hu zuo yong ,ke yi fa xian geng duo ju you you yi xing neng de cai liao zu ge ,wei shi xian wei xiao xing duo gong neng qi jian di gong ji yu 。ben lun wen tan jiu le dian chang he guang dui ji chong yang hua wu bao mo ci xing de diao kong ,ji zhu yao nei rong ru xia :(1)wo men shi yong she pin ci kong jian she ji shu zhi bei le ZnObao mo ,gai bao mo ju you shi wen tie ci xing ,ji ci xing lai yuan shi yang kong wei 。sui hou zhi bei cheng de ITO/ZnO/Ptqi jian ju you shuang ji xing zu bian ,ji zu bian ji li shi dian chang diao jie de yang kong wei dao dian xi si de xing cheng yu duan lie 。gai qi jian de zu bian xiao ying ye shou zi wai guang de ying xiang ,biao xian zai qi jian dian liu de zeng da he she zhi dian ya de jian xiao 。zhe ge xian xiang shi you guang zhao shi ZnObiao mian yang de jie xi fu suo dao zhi de 。ITO/ZnO/Ptqi jian zai gao di zu tai shi de ci xing ye bu xiang tong ,di zu tai shi qi jian de ci xing gao yu gao zu tai shi de ci xing ,ji yuan yin shi di dian zu tai shi ZnObao mo nei yang kong wei han liang geng gao 。guang zhao ke yi shi qi jian gao di zu tai de ci xing dou zeng jiang ,zhe ge xian xiang yu guang zhao hou yang kong wei lei xing de zhuai bian you guan 。ZnObao mo biao xian chu de zu bian xiao ying ji ci xing zhuai bian ke neng zai duo tai cun chu ling yu fa hui yi ding de ying yong 。(2)tong guo dui guang zhi fa guang guang pu de yan jiu ,wo men zheng shi ZnObao mo de shi wen tie ci xing lai yuan yu chan dian li yang kong wei (Vo+)。Pt/Ti/SiO2/Sichen de shang ZnOde ci xing zai zi wai guang he zi guang de zhao she xia hui zeng jiang 。ji zhu yao yuan yin shi guang sheng dian zi bei shuang dian li yang kong wei (Vo++)bu huo suo dao zhi de chan dian li yang kong wei (Vo+)zeng duo 。MgOchen de shang ZnOci xing diao kong de dui bi jie guo xian shi nei jian dian chang zai gai guo cheng zhong qi dao le chong yao zuo yong 。guang dui ZnOci xing de gai bian xu yao yi duan shi jian cai neng hui fu ,zhe yu ZnObao mo biao mian yang fen zi de zai xi fu you guan 。fei pian zhen guang zai shi wen tiao jian xia diao kong ZnOde ci xing ke neng zai guang ci ou ge qi jian zhong ju you yi ding qian zai de ying yong 。(3)wo men shi yong she pin ci kong jian she ji shu zhi bei le TiO2bao mo ,sheng chang zai Ag/Ti/Si02/Sihe Pt/Ti/SiO2/Sichen de shang de TiO2bao mo ju you shi wen tie ci xing ,bing ju chan dian li yang kong wei (Vo+)bei ren wei shi ji ci xing de lai yuan 。liang chong chen de shang TiO2bao mo de ci xing dou ke yi bei zi guang suo diao kong ,bing ju Agchen de shang bao mo de ci xing hai ke yi bei lan guang suo diao kong ,wo men ren wei Agjin shu ke li de ju yu biao mian deng li ji yuan xiao ying shi gai xian xiang chan sheng de yuan yin 。wo men tong guo EDSce shi fa xian Agkuo san jin ru bao mo yao bi Ptduo yi xie 。tong shi ,Agdui TiO2de guang xi shou ye chan sheng le ying xiang ,shi ji ke xi shou de ke jian guang fan wei zeng da 。Agjin shu ke li de ju yu biao mian deng li ji yuan xiao ying hui dao zhi biao mian zeng jiang la man san she ,ce shi jie guo xian shi Agchen de shang TiO2de la man feng ming xian zeng jiang 。Agjin shu ke li de ju yu biao mian deng li ji yuan xiao ying shi de TiO2bao mo ke yi xi shou bu fen lan guang ,cong er shi zi shen ci xing fa sheng gai bian 。(4)wo men zai Pt/Ti/SiO2/Sichen de shang sheng chang de CuxObao mo ju you shi wen tie ci xing ,shi yan yan jiu fa xian ji ci xing lai yuan ke neng shi jian jie shuang jiao huan zuo yong (Cu+-Vo-Cu2+)he yi bu fen yang kong wei 。CuxObao mo ci xing zai guang zhao xia hui fa sheng gai bian ,bing ju pin lv gao de guang dui ci xing ying xiang geng da 。tong guo guang zhao dui bu tong chen de shang CuxObao mo ci xing ying xiang de shi yan ,ke yi fa xian jie mian chu xing cheng de nei jian dian chang dui ci xing bian hua qi chong yao zuo yong ,ta ke yi you xiao de fen li guang sheng dian zi -kong xue dui 。guang sheng kong xue he dian zi zai qian yi guo cheng zhong de fu huo ke neng dao zhi Culi zi zai ju bu ou yu de jia tai zhuai bian ,xing cheng geng duo de Cu+-Vo-Cu2+,bing zeng jiang tie ci xing 。bu fen bu can yu jian jie shuang jiao huan zuo yong de yang kong wei ye ke neng bu huo shao liang guang sheng dian zi ,dui ci xing chan sheng ying xiang 。wo men fa xian Ag/CuxO/Nb:SrTi03/Agqi jian ju you te shu de zu bian xiao ying ,ji dian liu -dian ya qu xian cun zai ming xian de zheng liu te xing 。gai qi jian zai dian zu bian hua shi ban sui wen ding de ci xing bian hua 。qi jian de dian zu zhuai bian lai yuan yu dian chang zuo yong xia yang kong wei qian yi yin qi de jie mian chu lei xiao te ji shi lei gao du de bian hua 。jian jie shuang jiao huan zuo yong (Cu+-Vo-Cu2+)ke yi yong lai jie shi CuxObao mo de ci xing ,yang kong wei zai gai jian jie jiao huan zhong qi mei jie zuo yong 。bu tong dian chang xia ,jie mian shi lei gao du bu xiang tong ,cong er qi jian dian zu zhuang tai bu xiang tong ,er jue ding jie mian shi lei gao du de yang kong wei you zhi jie ying xiang ci xing ,dao zhi le bu tong dian zu tai xia ci xing da xiao ye bu tong 。Ag/CuxO/Nb:SrTiO3/Agqi jian ci xing zai shi wen xia ye ke yi bei guang suo diao kong 。ji yuan yin ke neng shi guang sheng kong xue huo dian zi de bu huo ,dao zhi ju bu Culi zi hua ge jia de zhuai bian ,jin er ying xiang jian jie shuang jiao huan zuo yong 。(5)wo men zhi bei de Ta/La2/3Sr1/3MnO3/Nb:SrTiO3/Agqi jian tong shi ju you zu bian xiao ying he ci xing diao kong 。gai qi jian de zu bian xiao ying shou shi jia dian chang shi yang li zi de qian yi he jie mian lei xiao te ji shi lei de gong tong ying xiang 。zai bu tong de dian chang xia ,yang li zi de qian yi fang xiang shi bu tong de ,zheng xiang dian chang hui shi yang li zi qian yi hou zai bao mo zhong liu xia yang kong wei ,yang kong wei de zeng duo hui zhu jian xing cheng yang kong wei dao dian xi si huo dao dian ou yu ,guan chuan jie mian lei xiao te ji shi lei ou yu ,shi qi jian jin ru di zu tai 。shi jia fu xiang dian chang shi ,yang li zi hui tian yang kong wei ,dao dian xi si huo dao dian ou yu duan lie ,jie mian shi lei hui fu dao yuan xian zhuang tai ,qi jian chong hui gao zu tai 。qi jian de zu bian xiao ying ye ban sui ci xing bian hua ,qi jian zai gao di zu tai shi de ci xing da xiao ye bu xiang tong ,ji yuan yin shi yang li zi de qian yi ying xiang le shuang jiao huan zuo yong 。La2/3Sr1/3MnO3/Nb:SrTiO3de ci xing zai 70Kke yi bei guang suo diao kong ,zhu yao yuan yin ke neng shi guang sheng dian zi gai bian le fei mi mian shang de dian zi gui dao zhan ju ,ying xiang le bao mo ci ge xiang yi xing ,jin er gai bian le bao mo de jiao wan li 。wo men tan jiu de ji chong yang hua wu bao mo de ci xing lai yuan zhu yao shi yang kong wei 、yang kong wei jie dao de jian jie shuang jiao huan zuo yong he shuang jiao huan zuo yong ,ji zhong qian liang chong lei xing ci xing xiang dui jiao ruo ,di san chong lei xing ci xing xiang dui jiao jiang 。dian chang shi yi ge jiang de wai chang ,ke yi zai shi wen xia zhi jie gai bian cai liao de ci xing ,er guang shi yi chong xiang dui jiao ruo de wai chang ,shi wen shi zhi neng gai bian jiao ruo de ci xing ,di wen shi cai neng gai bian jiao jiang de ci xing 。wo men dui yang hua wu bao mo ci xing diao kong de yan jiu ke neng dui shi ji qi jian de ying yong you yi ding de bang zhu 。
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论文作者分别是来自山东大学的谢继浩，发表于刊物山东大学2019-07-16论文，是一篇关于氧化物薄膜论文,电阻转变论文,电场调控磁性论文,光调控磁性论文,山东大学2019-07-16论文的文章。本文可供学术参考使用，各位学者可以免费参考阅读下载，文章观点不代表本站观点，资料来自山东大学2019-07-16论文网站，若本站收录的文献无意侵犯了您的著作版权，请联系我们删除。
标签：氧化物薄膜论文; 电阻转变论文; 电场调控磁性论文; 光调控磁性论文; 山东大学2019-07-16论文;