ZnO半导体粉体制备工艺与电阻率的关系

采用固相合成法制备了氧化铝掺杂的氧化锌半导体粉体,通过X-射线衍射分析,探讨了掺杂量、煅烧温度和保温时间对粉体导电性能的影响.实验发现:Al2O3的掺杂量高于0.5%(摩尔比)时,会生成ZnAl2O4尖晶石相,降低ZnO的电导率;在一定的温度和保温时间下,才能保证有足够的Al3 进入ZnO的晶格,从而获得电阻率比较低的ZnO半导体粉体;温度过高和保温时间过长都会导致Al2O3与ZnO反应生成尖晶石,减少Al3 对Zn2 的置换率,并对电子产生散射,从而导致ZnO半导体粉体的电阻率升高;当Al2O3掺杂量为ZnO的0.5%(摩尔比)时,在1300℃下保温3h所得到的ZnO粉体的电阻率为18kΩ.cm.     

溶胶-凝胶旋涂法制备Al掺杂ZnO薄膜及其光电性能的研究

利用溶胶-凝胶(sol-gel)旋涂法制备不同Al掺杂量的ZnO薄膜.采用X射线衍射仪(XRD)、扫描电子显微镜(SEM)、紫外可见分光光度计(UV-Vis)和光致发光谱(PL)等测试手段对Al掺杂ZnO薄膜的晶体结构、表面形貌及光电性能进行表征.结果表明:所制备的样品均沿(002)方向择优生长,无其他杂相的出现.随着Al掺杂量的增加,薄膜的晶粒尺寸先减小后增大,当Al掺杂量为0.020时晶粒尺寸最小,其表面晶粒最为均匀、致密;近紫外发光峰的强度先增强后减弱,并且出现了轻微蓝移的现象;薄膜的电阻值先减小后轻微增大.当Al元素的掺杂量为0.015时,薄膜表面相对均匀致密,禁带宽度有所增加,可见光范围内平均透过率最高达到90%,并且具有较好的导电性能.     

ZAO透明导电纳米薄膜中Al元素分布对其性能的影响

主要对直流反应磁控溅射法制备ZAO纳米薄膜中Al元素的相对含量进行了分析,对其作了EDS,XRD测试,并研究了Al质量分数与ZAO薄膜的光、电性能的关系·得出ZAO薄膜中成分是均匀的,具有ZnO晶体结构;Al元素的掺杂没有形成新的化合物(Al2O3),Al对Zn的掺杂替换是提高ZAO薄膜导电性能的关键因素,对薄膜在可见光区的透射性影响不大·制备的薄膜最低电阻率为4 5×10-4Ω·cm,可见光透射率达到80%以上·     

纳米ZnO阵列场发射性能研究

目的 为了进一步提高ZnO纳米阵列的场发射性能指标.方法 采用掺杂n型杂质元素Al和衬底预处理的方法生长ZnO纳米阵列,对相应样品的场发射性能进行比较分析.结果 和结论采用Al掺杂和衬底镀Au处理均提高了ZnO纳米阵列场发射的性能,降低了阈值场强.其中衬底镀Au并在此衬底上生长的Al掺杂ZnO纳米阵列开启电场小于0.5 V/μm、阈值电场为4.5 V/μm.     

ZnO:Al透明导电薄膜的制备及其光电性能的研究

利用溶胶-凝胶法在石英衬底上制备Al3+掺杂ZnO薄膜,研究了Al3+掺杂对ZnO薄膜微结构和光学性能的影响.XRD测量结果表明,Zn1-xAlxO薄膜具有六角纤锌矿结构,晶格常数随着Al掺杂浓度的增加而减小;紫外-可见透射光谱(UV)表明,所有薄膜在可见光区的透过率均超过80%;光致发光谱研究发现,随着Al掺杂浓度的增加ZnO的吸收带边发生蓝移,XRD和光学性能研究都证实了ZnO薄膜中的Al3+是以替位式形式存在于晶格中.     

氧化锌透明导电膜的光电性能研究

采用磁控溅射法在载玻片上制备出Al3 掺杂型ZnO透明导电薄膜.对不同厚度薄膜的光电性能进行了研究.结果表明,所制备的薄膜随着厚度的增加,透过率略有下降;ZnO薄膜在可见光区的吸光度很小,对可见光几乎不吸收.     

Al掺杂ZnO纳米颗粒的光催化性能

溶胶-凝胶法合成ZnO和Al掺杂ZnO(AZO),通过降解甲基橙(MO)评价纳米颗粒的光催化性能.与纯ZnO相比,Al掺杂使ZnO晶粒尺寸减小,比表面积增加.此外,Al掺杂诱发高浓度缺陷,从而调整ZnO晶体的能带结构.电子从导带跃迁到低能态的缺陷能级,能量差与可见光的能量吻合,从而大幅提高光催化过程中对可见光的利用率.AZO样品在可见光范围内都表现出优异的光催化性能,并且a(Al)=3%掺杂的ZnO表现出最佳的光催化性能,60 min降解效率为94%.     

Al_2O_3掺杂对ZnO纳米粉体气敏性能的影响

采用溶胶-凝胶法制备了ZnO及掺铝ZnO纳米粉体.利用X射线粉末衍射仪、透射电镜对材料的结构进行了表征.结果表明制备的ZnO及掺铝ZnO纳米材料均属于六方晶系,纤锌矿结构.用纯ZnO和掺铝ZnO做成气敏元件,研究了不同掺杂量对材料的气敏性能的影响.结果表明,铝掺杂均使ZnO对体积分数30×10-6的Cl2的灵敏度有很大的提高,当铝含量为Al2O3/ZnO=0.5%(mol)时,对30×10-6Cl2的灵敏度最高可达800左右.并讨论了纳米氧化物的气敏机理.     

均匀沉淀法制备ZAO纳米棒

采用均匀沉淀法,以尿素、Zn(NO3)2·6H2O和Al(NO3)3·9H2O为原料,在水乙二醇溶液中制备了Al掺杂ZnO(ZAO)纳米棒.X射线衍射(XRD)分析表明:纳米棒为六方纤锌矿结构,掺杂的Al3+取代了Zn2+的位置,形成A1/ZnO固溶体,保持了ZnO的结构.前驱体的红外光谱(FTIR)分析表明:乙二醇的加入改变了纳米材料的表面状态.扫描电镜(SEM)和高分辨透射电镜(TEM)结果显示:随着反应体系中乙二醇体积比和Al掺杂量的增加,ZAO纳米棒的长径比先增大后减小,在V(水)/V(乙二醇)=4、Al掺杂量为5%(摩尔分数)时,制得长径比最大为25、直径为10 nm的纳米棒.     

Al_2O_3掺杂ZnO线性电阻的性能及其显微组织

通过高能球磨法,分别在1 250,1 300,1 350℃下制备了掺杂量为3.5%,4.0%,4.5%,5.0%的Al2O3掺ZnO线性电阻,通过扫描电镜和X射线衍射对其显微组织和相成分进行了分析,探讨了不同Al2O3掺杂量和不同烧结温度对ZnO线性电阻的线性性能和介电性能的影响.结果表明:掺杂A12O3的ZnO线性电阻主晶相为ZnO,并伴随有少量锌尖晶石相生成.在烧结温度为1 350℃,Al2O3掺杂摩尔分数为3.5%时,线性电阻性能最优,其非线性系数为1.00.另外,随A12O3掺杂量增大,ZnO线性电阻的介电常数变化不大,而烧结温度对陶瓷的介电常数有较为明显的影响.     

Influence of Al doping on the crystal structure,optical properties,and photodetecting performance of ZnO film

The structural,optical,and electrical properties of undoped and Al-doped ZnO films deposited on p-Si(001)substrate were studied using DC-unbalanced magnetron sputtering.This study is motivated by the absence of detail reports concerning the orbital states inducing the optical bandgap(E_g) blueshift.Besides,the influences of Al on the possible modification of point defect and the photodetecting performance are highlighted to offer guidelines for better development in ZnO-based photodetector.It was found that the Al doping reduced the grain size.The doping increased the lattice parameters and slightly decreased the local-symmetry distortion at ZnO_4.From the absorbance spectra,the doping increased Eg of ZnO film(3.28-3.36 eV),induced by the Burstein-Moss effect.From the density-functional calculation,the Burstein-Moss effect induced E_g from the valence band maximum(VBM) to Fermi level located above the lowest Zn 4s conduction state.From the photoluminescence spectra,the undoped film showed the transitions from O vacancy,Zn interstitial,and free-exciton states to the VBM.The doped film showed the transitions from Zn interstitial to O interstitial and few Zn vacancy states at the cost of O vacancies.Moreover,the energy level of free-exciton states slightly decreased.Notably,O interstitials increased the lattice parameters.From the electrical properties,the doping enhanced the ultraviolet-region photo-to-dark-current ratio up to 3.044 V,leading to the photodetecting sensitivity enhancement.This study emphasizes the significant effect of Al doping on the optical absorbance,point-defect evolution,and photodetecting performance of ZnO film for low-voltage ultraviolet photodetector applications.     

Study on ZnO:Al (ZAO) films by DC reaction magnetron sputtering

The high quality ZnO: A1 films were successfully produced by DC reaction magnetron sputtering technology. The Al-doping effect on electrical and optical properties and its scattering mechanism are discussed in detail. The analyses of X-ray diffractometer (XRD), X-ray photoelectron spectroscopy(XPS) and high resolution Auger electron spectroscopy (AES) show that Al2O3 could be effectively removed by controlling oxygen flow and Al-doping concentration during deposition of ZnO: Al films. Zn, Al and oxygen elements are well distributed through the films. For highly degenerated ZnO:A1 semi-conductive thin films, the theoretical and experimental results reveal that the ionized impurity. scattering dominates the Hall mobility in the films in the low-temperature range, while the lattice vibration scattering becomes a major scattering mechanism in the high-temperature range. The grain boundary scattering only plays a major role in the ZAO films with small grain size (as compared to the electron mean free path). The photoelectric properties of ZAO films show that it has low resistivity ( ～ 5 × 10-4 Ωcm), and the transmittance in visible range and the reflectance in IR region are above 80% and 60%, respectively.     

Photore sponse and H2 gas sensing properti es of highly oriented Al and Al/Sb doped ZnO thin films

ZnO:Al and ZnO:Al/Sb thin films have been prepared and investigated.The thin films were deposited on Si substrates by the sol-gel method.The structural,optical and electrical properties of ZnO films have been investigated by spectrophotometry,ellipsometry,X-ray diffraction and current-voltage characterizations.It is found that the films exhibit wurtzite structure with a highly c-axis orientation perpendicular to the surface of the substrate,a high reflectivity in the infrared region and a response to illumination.Furthermore,it has been found that Si/（ZnO:Al/Sb）/Al photodiode is promising in photoconduction device while Si/（ZnO:Al）/Al can be used as gas sensor responding to the low H₂concentrations.     

Zn1-xAlxO粉末样品的制备及结构表征

采用固相反应法制备了Zn1-xAlxO粉末样品。通过X射线衍射(XRD)和红外光谱(IR)对粉体的结构和光学性能进行了表征。结果表明:随着Al掺杂浓度逐渐加大,样品ZnO(101)衍射峰的峰位向高衍射角方向移动,x=0.024样品的晶粒大小随温度的升高而增大;通过FT-IR发现Al掺杂样品在427.78 cm-1和487.39 cm-1附近出现了Zn-O的吸收带,表现出良好的红外吸收特性。     

热处理温度及冷却速度对ZnO:Al薄膜性能的影响

采用溶胶一凝胶法在普通玻璃衬底上制备出了Al3+离子掺杂的ZnO(ZnO:Al)透明导电薄膜.利用X射线衍射仪(XRD)、扫描电子显微镜(SEM)、四探针法及紫外-可见分光光度计(UV-VIS)等分析方法对制备的薄膜进行了表征,研究了热处理温度及冷却速度对ZnO:Al薄膜结晶状况、电阻率、可见光透过率的影响.研究发现:制备的薄膜为具有沿(002)晶面择优取向的ZnO六角纤锌矿结构,适当的热处理温度和冷却速度有利于改善ZnO:Al薄膜的导电性,并且当采用快速冷却时薄膜的导电性明显增强,而透光率略微减小.500℃热处理1 h后,-15℃环境中快速冷却相对于随炉冷却和空气中冷却制备的薄膜电阻率有大幅度的降低,达到0.22Ω·cm,透光率大于80%.     

Preparation and properties of AZO thin films on different substrates

Al doped ZnO (AZO) films were deposited on glass, polyethylene naphthalate (P EN) and polyethylene terephthalate (PET) at room temperature by radio frequency magnetron sputtering. The structural, surface morphology, electrical and optical properties of the AZO films were characterized by X-ray diffractometry (XRD), atomic force microscopy (AFM), Hall effect measurement and ultraviolet-visible spectrometer, respectively. The films exhibit highly c-axis preferred orientation, a nd AZO film on glass exhibits compressive stress while that on plastic subs trates presents tensile stress. The electr ical property of the AZO film on glass is the best among the films on three kinds of substrates. The value of the figure of merit for the AZO film on PEN is much better than that of the AZO film on PET and is close to that of AZO on glass in the wavelength range of 500? 900 nm.     

Al-N 共掺杂p 型ZnO 薄膜制备及电学性能的研究

利用射频磁控溅射技术在石英玻璃上制备了ZnO:Al薄膜,继而N离子注入实现薄膜的Al-N共掺杂,随后进行了不同温度和时间的热处理。并借助X射线衍射(XRD)、霍耳测试(Hall)、X射线光电能谱仪(XPS)等手段对ZnO薄膜的性能进行了表征。实验结果表明,Al-N共掺杂ZnO薄膜在578℃退火8 min表现出较稳定的p型导电,其载流子数高达1×1018～6×1018个·cm-3,对应的电阻率为1～9Ω·cm,迁移率为1～2 cm2·V-1·s-1。与单掺N相比,实现p型导电所需的退火温度有明显降低,这很可能与Al的掺入有关。此外,XPS测试结果证实大量的Ni取代O空位是薄膜p型导电的根本原因。     

Structural and electrical properties of ZnO films on freestanding thick diamond films

In this paper, ZnO films are deposited on freestanding thick diamond films （FTDF） by plasma-assisted metal organic chemical vapour deposition （MOCVD）. Diethyl zinc （DEZn）, O2 and N2O are applied as precursors and different substrate temperatures are used to achieve high quality ZnO films. The influence of substrate temperature on the properties of ZnO films is systematically investigated by X-ray diffraction （XRD）, Hall measurements and electron probe microanalysis （EPMA）. Experimental results demonstrate that ZnO films deposited at 600℃ and 73 Pa display a fine electrical quality and Zn/O atomic ratio plays an important role in the electrical property of ZnO films.