氢处理ZnO基薄膜的光电性能分析和氢相关缺陷作用机理
发布时间：2018-12-09 09:52
【摘要】：本论文采用射频磁控溅射法,用两种不同的途径制备ZnO基透明导电薄膜:(1)分别在通氧和未通氧气氛中制备ZnO薄膜和ZnO:Al(AZO)薄膜,随后将薄膜在Ar+H_2中进行退火处理;(2)在Ar+H_2气氛中直接制备ZnO基薄膜。利用XRD、霍尔效应、XPS、PL、透射光谱等测试表征手段,分析了薄膜的晶体结构、光电性能、缺陷态以及元素的化学态。在此基础上,对H相关缺陷态影响薄膜性能的机理进行了深入分析。研究了H_2退火对不同气氛制备的ZnO薄膜性能的影响。H_2退火前后,ZnO薄膜均为c轴择优取向的六方纤锌矿结构,H_2退火可以显著改善薄膜的结晶质量。H_2退火未对薄膜在可见光区的透过率产生明显影响,所有薄膜的平均透过率都大于85%。通氧制备的ZnO薄膜以O原子为终止面(O-face),薄膜中存在较多的吸附氧和O_i、V_zn等本征缺陷,它们都起到受主的作用,受主的补偿和散射作用导致薄膜导电性不好。退火后,H将钝化上述受主,造成吸附氧的脱附、形成复合体(如V_zn-H_n)和O_i逸出等,同时薄膜结晶质量的提高也会造成迁移率的增大,因此薄膜的导电性能大为改善。未通氧制备的ZnO薄膜为以Zn原子为终止面(Zn-face),薄膜中的吸附氧和O_i等受主必然会比较少,因此薄膜具有较好的导电性。H_2退火处理后薄膜中会产生更多的受主V_zn,因此薄膜的导电性能变差。研究了H_2退火对不同气氛制备的AZO薄膜性能的影响。H_2退火未对薄膜的结晶质量和透过率产生明显影响。H_2退火后,通氧制备的AZO薄膜的电阻率明显降低,是H对受主的钝化作用改善了薄膜的导电性能,这点与ZnO薄膜的结果一致。对未通氧制备的AZO薄膜,H_2退火后薄膜的电阻率基本保持不变,这点与ZnO薄膜的结果不同。原因是Al掺杂造成了薄膜极性的改变,导致H_2退火后薄膜中不会产生大量的受主V_zn,同时薄膜中的本底载流子浓度较高,H对V_zn的钝化作用不会对薄膜的电学性能造成明显影响。虽然H_2退火后通氧制备的AZO薄膜的导电性得到极大的改善,却依然无法超越未通氧环境下制备的AZO薄膜。研究了H_2流量比对ZnO和AZO薄膜性能的影响。制备过程通氢对ZnO薄膜的结晶质量影响不大,却可导致AZO薄膜的结晶质量变差。所有通氢制备的薄膜在可见光范围透过率均大于85%。通氢后ZnO、AZO薄膜的电阻率都出现大幅降低。研究表明,制备过程通氢并没有影响薄膜中的Al含量和Al、Zn的化学态,H作为浅施主也不可能大幅改善薄膜导电性,仍然是H钝化受主的作用造成薄膜导电性能的改善。制备过程通氢相比H_2退火而言,能更有效地降低薄膜的电阻率。原因可能是制备过程通氢更有利于H深入薄膜内部,钝化受主,改善薄膜电学性能。
[Abstract]:In this thesis, ZnO thin films were prepared by RF magnetron sputtering in two different ways: (1) ZnO and ZnO:Al (AZO) thin films were prepared in oxygen and unoxygenated atmosphere, respectively. The films were then annealed in Ar H2. (2) ZnO based films were prepared directly in Ar H _ 2 atmosphere. The crystal structure, photoelectric properties, defect states and chemical states of the films were analyzed by means of XRD, Hall effect and XPS,PL, transmission spectroscopy. On this basis, the mechanism of the influence of H-related defect states on the film properties was analyzed. The effect of HZ _ 2 annealing on the properties of ZnO thin films prepared in different atmospheres was studied. Before and after annealing, the ZnO films were all hexagonal wurtzite structures with c-axis preferred orientation. H2 annealing can significantly improve the crystalline quality of the films. H2 annealing has no significant effect on the transmittance of the films in the visible region, and the average transmittance of all the films is greater than 85g. O atoms are the termination surface (O-face) in the ZnO films prepared by oxygen transfer, and there are many intrinsic defects such as oxygen adsorption and the intrinsic defects such as OSCH VZ n in the films, which all play the role of acceptor. The compensation and scattering of the acceptor lead to the poor conductivity of the film. After annealing, H passivates the above-mentioned acceptor, resulting in the desorption of adsorbed oxygen, the formation of complex (such as V_zn-H_n) and the escape of O _ I, and the increase of the crystalline quality of the film, which also results in the increase of the mobility. As a result, the conductive properties of the films are greatly improved. The ZnO thin films prepared by unoxygenation have Zn atoms as the termination surface (Zn-face), so the number of acceptors such as oxygen adsorption and O _ s _ I in the films is bound to be relatively small. As a result, the thin films have good conductivity. After annealing, more acceptors will be produced in the films, so the conductive properties of the films become worse. The effect of Hal _ 2 annealing on the properties of AZO thin films prepared in different atmospheres was studied. The crystallization quality and transmittance of AZO films were not significantly affected by H _ s _ 2 annealing. The resistivity of AZO thin films prepared by H _ (2) annealing decreased obviously after annealing. The passivation of the acceptor by H improves the conductivity of the film, which is consistent with the results of the ZnO film. The resistivity of AZO thin films annealed by H _ S _ 2 remains basically the same as that of ZnO films, which is different from that of ZnO films. The reason is that Al doping changes the polarity of the films, resulting in no large number of acceptor VZN in the H2 annealed films, and the higher carrier concentration in the films. The passivation of V_zn by H has no obvious effect on the electrical properties of the films. Although the conductivity of AZO thin films prepared by H _ S _ 2 annealing has been greatly improved, it is still no better than that of AZO films prepared in non-oxygen environment. The effect of flow ratio of Hap2 on the properties of ZnO and AZO films was studied. The effect of hydrogen flux on the crystallization quality of ZnO thin films is not significant, but the crystallization quality of AZO thin films becomes worse. The transmittance of all the films prepared by hydrogen permeation is greater than 855in the visible range. The resistivity of ZnO,AZO films decreased significantly after hydrogen transfer. The results show that the hydrogen flux has no effect on the Al content and the chemical state of Al,Zn in the thin films. As a shallow donor, H can not improve the conductivity of the thin films significantly. It is still the H passivation acceptor that results in the improvement of the conductivity of the thin films. Compared with H _ S _ 2 annealing, the resistivity of the thin films can be reduced more effectively by the preparation of hydrogen. The reason may be that hydrogen permeation is more favorable for H to go deep into the film, passivate the acceptor and improve the electrical properties of the film.
【学位授予单位】：深圳大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：O614.241;TB383.2
本文编号：2369188
[Abstract]:In this thesis, ZnO thin films were prepared by RF magnetron sputtering in two different ways: (1) ZnO and ZnO:Al (AZO) thin films were prepared in oxygen and unoxygenated atmosphere, respectively. The films were then annealed in Ar H2. (2) ZnO based films were prepared directly in Ar H _ 2 atmosphere. The crystal structure, photoelectric properties, defect states and chemical states of the films were analyzed by means of XRD, Hall effect and XPS,PL, transmission spectroscopy. On this basis, the mechanism of the influence of H-related defect states on the film properties was analyzed. The effect of HZ _ 2 annealing on the properties of ZnO thin films prepared in different atmospheres was studied. Before and after annealing, the ZnO films were all hexagonal wurtzite structures with c-axis preferred orientation. H2 annealing can significantly improve the crystalline quality of the films. H2 annealing has no significant effect on the transmittance of the films in the visible region, and the average transmittance of all the films is greater than 85g. O atoms are the termination surface (O-face) in the ZnO films prepared by oxygen transfer, and there are many intrinsic defects such as oxygen adsorption and the intrinsic defects such as OSCH VZ n in the films, which all play the role of acceptor. The compensation and scattering of the acceptor lead to the poor conductivity of the film. After annealing, H passivates the above-mentioned acceptor, resulting in the desorption of adsorbed oxygen, the formation of complex (such as V_zn-H_n) and the escape of O _ I, and the increase of the crystalline quality of the film, which also results in the increase of the mobility. As a result, the conductive properties of the films are greatly improved. The ZnO thin films prepared by unoxygenation have Zn atoms as the termination surface (Zn-face), so the number of acceptors such as oxygen adsorption and O _ s _ I in the films is bound to be relatively small. As a result, the thin films have good conductivity. After annealing, more acceptors will be produced in the films, so the conductive properties of the films become worse. The effect of Hal _ 2 annealing on the properties of AZO thin films prepared in different atmospheres was studied. The crystallization quality and transmittance of AZO films were not significantly affected by H _ s _ 2 annealing. The resistivity of AZO thin films prepared by H _ (2) annealing decreased obviously after annealing. The passivation of the acceptor by H improves the conductivity of the film, which is consistent with the results of the ZnO film. The resistivity of AZO thin films annealed by H _ S _ 2 remains basically the same as that of ZnO films, which is different from that of ZnO films. The reason is that Al doping changes the polarity of the films, resulting in no large number of acceptor VZN in the H2 annealed films, and the higher carrier concentration in the films. The passivation of V_zn by H has no obvious effect on the electrical properties of the films. Although the conductivity of AZO thin films prepared by H _ S _ 2 annealing has been greatly improved, it is still no better than that of AZO films prepared in non-oxygen environment. The effect of flow ratio of Hap2 on the properties of ZnO and AZO films was studied. The effect of hydrogen flux on the crystallization quality of ZnO thin films is not significant, but the crystallization quality of AZO thin films becomes worse. The transmittance of all the films prepared by hydrogen permeation is greater than 855in the visible range. The resistivity of ZnO,AZO films decreased significantly after hydrogen transfer. The results show that the hydrogen flux has no effect on the Al content and the chemical state of Al,Zn in the thin films. As a shallow donor, H can not improve the conductivity of the thin films significantly. It is still the H passivation acceptor that results in the improvement of the conductivity of the thin films. Compared with H _ S _ 2 annealing, the resistivity of the thin films can be reduced more effectively by the preparation of hydrogen. The reason may be that hydrogen permeation is more favorable for H to go deep into the film, passivate the acceptor and improve the electrical properties of the film.
【学位授予单位】：深圳大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：O614.241;TB383.2
【参考文献】
相关期刊论文 前1条
1 宋秋明;吕明昌;谭兴;张康;杨春雷;;H/Al共掺杂对ZnO基透明导电薄膜光电性质和晶体结构的影响[J];发光学报;2014年04期
，本文编号：2369188
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