溅射压强对W掺杂ZnO薄膜结构及光学性能的影响

在不同溅射压强下,通过射频(RF)磁控溅射在石英玻璃衬底上沉积得到W掺杂ZnO薄膜(WZO).对样品的结晶性能,表面形貌和光学性能进行测试分析,结果表明:在适当溅射压强下,薄膜具有良好的结晶性和光学性能.随着溅射压强的增加,薄膜的结晶性先变好后变差,晶粒尺寸先增大后减小,在1.0 Pa时薄膜的结晶性最好,且晶粒尺寸最大,约为32 nm;所有WZO薄膜样品的平均透光率超过80;;光致发光主要由本征发光和缺陷引起的蓝光发光组成,在1.0Pa时薄膜还有明显的Zn;缺陷,在1.2Pa时薄膜有明显的Oi缺陷.     

金属Ta缓冲层上生长微晶Si薄膜的结晶性研究

利用射频磁控溅射技术,在生长了Ta缓冲层的石英玻璃衬底上采用不同溅射功率下制备了一系列的硅薄膜样品,用拉曼光谱和X射线衍射表征了薄膜的结晶性随溅射功率的变化情况.实验结果表明:随着溅射功率的增加,薄膜逐渐由非晶向微晶过渡,晶粒沿Si(311)面呈柱状生长,功率升高到80 W时薄膜的晶化率达到75.4;,薄膜为典型的微晶结构.继续增加功率,薄膜的结晶性变差,晶化率下降,在60～120 W之间存在一个优化理想的射频溅射功率,在此功率下生长的薄膜样品的结晶性最高.本文还尝试解释了Ta缓冲层在Si晶化过程中的作用.     

射频磁控溅射生长ZnO薄膜及性能研究

采用射频磁控溅射技术在玻璃衬底生长ZnO及ZnO∶ Al薄膜,通过改变氩氧比、衬底温度和溅射功率获得样品.用X射线衍射仪、紫外-可见分光光度计、扫描电子显微镜进行表征.结果发现:室温下40W的溅射功率1h的溅射时间,改变氩氧比获得样品.XRD图谱中无明显衍射峰出现;紫外可见光分光光度计测试结果显示400nm波长以下,透光率在90;以上.说明薄膜生长呈无定形.衬底温度高于200℃样品,XRD有明显(002)衍射峰出现,在400～ 800 nm波长范围,透光率在88;以上,衬底温度300℃时,XRD衍射峰半高宽最小,晶粒尺寸大.TEM显示:衬底300℃晶粒尺寸最大,晶体发育好.在200℃掺铝ZnO薄膜,(002)峰不明显,有(101)峰出现.     

溅射功率对硫化镉薄膜结构和光电性能的影响

在玻璃衬底上采用射频磁控溅射方法制备了硫化镉(CdS)薄膜,研究了溅射功率对CdS薄膜的结构、表面形貌、光学特性和电学性质的影响.XRD测量表明制备的CdS薄膜均为六方纤锌矿结构的多晶薄膜.随着功率从40 W增加到80 W,H(102)面的峰呈现增强再逐渐减弱的趋势.60 W时薄膜的衍射峰最强,结晶度最好.同时,薄膜的晶粒尺寸随着功率增加先增大再减小.从SEM图像可以看出,制备的薄膜均匀致密且无针孔的出现.在可见光范围内,薄膜的平均透射率都在70;以上.随着功率的增加,薄膜带隙在2.25～2.41 eV的范围内变化,而暗电导率呈现先增加再减少的趋势.     

等离子体增强分子束外延生长ZnO薄膜及光电特性的研究

利用等离子体辅助分子束外延设备(P-MBE)在蓝宝石(Al2O3)衬底上外延生长ZnO薄膜,研究了不同生长温度对结晶质量的影响.随着生长温度的升高,X射线摇摆曲线(XRC)半高宽从0.88°变窄至 0.29°,从原子力显微镜(AFM)图像中发现薄膜中晶粒从20nm左右增大至200nm,室温光致发光(PL)谱中显示了一个近带边的紫外光发射(UVE)和一个与深中心有关的可见光发射.随着生长温度升高,可见光发射逐渐变弱,薄膜的室温载流子浓度由1.06×1019/cm3减少到7.66×1016/cm3,表明在高温下生长的薄膜中锌氧化学计量比趋于平衡,高质量的ZnO薄膜被获得.通过测量变温光谱,证实所有样品在室温下PL谱中紫外发光都来自于自由激子发射;随着生长温度的变化UVE峰位蓝移与晶粒尺寸不同引起的量子限域效应相关.     

溅射功率对射频磁控溅射制备非晶In-Ga-Zn-O薄膜的影响

采用射频磁控溅射法在室温玻璃衬底上成功地制备出了铟镓锌氧(In-Ga-Zn-O)透明导电薄膜.研究了不同溅射功率对In-Ga-Zn-O薄膜结构、电学和光学性能的影响.X射线衍射(XRD)表明,在80～150 W溅射功率范围内In-Ga-Zn-O薄膜为非晶结构.随着溅射功率的增加,生长速率成线性增加,电阻率逐渐降低.透射光谱显示在350 nm附近出现较陡的吸收边缘,说明In-Ga-Zn-O薄膜在以上溅射功率范围内具有良好的薄膜质量.光学禁带宽度随着溅射功率增加而减小.In-Ga-Zn-O薄膜在500～800nm可见光区平均透过率超过90;.     

(111)择优取向ZnS薄膜的制备及特性研究

采用激光分子束外延技术在Al2O3衬底上成功外延生长了ZnS薄膜.用X射线衍射、扫描电子显微镜和光致发光谱表征了衬底温度对薄膜结构、形貌和光学特性的影响.结果表明所生长的ZnS薄膜为闪锌矿,具有(111)择优长向,随衬底温度的升高,X射线衍射峰的半高宽先减小后增大,在衬底温度为300℃时,半高宽最窄.薄膜结构致密,表面不平整度随衬底温度的升高而增大.薄膜的带隙随衬底温度的升高出现蓝移,可见光区域透射率最高达到98;,在360 nm激发波长下,观测到402 nm和468 nm两个发光带,衬底温度为300℃时,发光最强.     

直流磁控溅射法制备铝铬共掺杂氧化锌薄膜及其结构和光电性能的研究

利用直流磁控溅射法在玻璃衬底上制备了铝铬共掺杂氧化锌(ZACO)透明导电薄膜.通过X射线衍射(XRD)和扫描电镜(SEM)等表征方法对薄膜特性进行测试分析,研究了溅射压强和溅射功率对薄膜生长速率以及光电特性的影响.结果表明,随着溅射气压(1.5～4.5 Pa)的增大,薄膜沿c轴方向的结晶质量提高,薄膜表面更加致密,晶粒大小更加均匀.薄膜生长率随压强的增大而减小,但电阻率先减小后增大.当溅射功率由80 W增大到100 W时,薄膜的生长速率增大,电阻率减小.溅射压强为3.5 Pa,溅射功率为100 W时,薄膜的电阻率达到最小值2.574×10-3 Ω·cm.紫外-可见透射光谱表明,所有薄膜在可见光区的透过率均超过89.9;.     

溅射压强对掺钛氧化锌纳米薄膜微结构和光电性能的影响

采用射频磁控溅射法,采用不同的溅射压强将同一掺钛氧化锌靶材在普通玻璃衬底上溅射出八个TZO(掺钛氧化锌)薄膜样品,测试其微结构和光电性能,分析其薄膜性能与溅射压强之间的微观机理,从而获得制备性能优越的TZO薄膜所需的最佳溅射压强.结果表明:所有样品均为具有c轴择优取向的六角铅锌矿多晶纳米薄膜;溅射压强对薄膜微结构和光电性能有显著的影响;溅射功率为150 W,氩气流量为25 sccm,衬底温度为150℃,压强为0.5 Pa时制备的薄膜光电性能较好,具有较大晶粒尺寸,在可见光区(400 ～ 760 nm)有较高的平均透过率达91.48;,较低电阻率4.13×10-4 Ω·cm,较高的载流子浓度和较大迁移率.     

纯氮气反应溅射AlN薄膜及性质研究

在不同氮气浓度、不同溅射气压和衬底温度为20～370 ℃的条件下,分别在多种衬底上采用反应磁控溅射法沉积AlN薄膜.X射线衍射图谱表明:温度大于180 ℃时可在多种衬底上沉积出具有c轴择优取向的纤锌矿AlN薄膜.衬底温度和溅射时间的增加有利于薄膜结晶性的改善. 1.5 Pa的纯氮气气氛和Si(100)衬底是最佳择优生长条件.由紫外-可见光透射谱计算得到:在石英衬底上沉积的薄膜折射率为1.80～1.85,膜厚约为 1 μm、光学能隙为6.1 eV.原子力显微镜照片表明:在Si(100)衬底上制备的薄膜表面平滑,均方根粗糙度为2.2～13.2 nm.     

Properties of Si-rich SiO2 films by RF magnetron sputtering

Si-rich silicon oxide (SiO_x, 1<x<2) films were prepared by RF magnetron reactive sputtering or co-sputtering on the Si(1 1 1) substrates. X-ray diffraction patterns showed that the peak of silicon nanocrystals (NCs), separated from SiO_x films, had (1 1 1) preferred orientation. The results of scanning electron microscopy indicated the Si NCs uniting into clusters. We demonstrated that the photoluminescence (PL) peaks at 650 nm was caused by defect center. In particular, we discussed the correlation between the PL and the structure of SiO_x films. The mean size of the Si NCs was estimated to be about 3 nm by the PL peak position.     

射频溅射功率对Mn-Co-Ni-O薄膜结构与性能的影响

采用射频磁控溅射技术在硅衬底上制备了锰钴镍氧(Mn-Co-Ni-O, MCNO)薄膜并进行了后退火处理。利用X射线衍射、扫描电子显微镜、光学测试仪器等测试手段对晶体结构、表面形貌及光学性能进行表征。分析了不同射频溅射功率(60~100 W)对MCNO薄膜表面微观形貌、晶体结构和光学性能的影响。结果表明,在60~90 W下获得的薄膜表面致密且均匀,但在100 W下获得的MCNO薄膜表面晶粒尺寸显著增大。物相分析表明,采用射频磁控溅射沉积的MCNO薄膜主要为尖晶石结构,溅射功率对薄膜结晶质量和择优取向具有显著影响,在80 W下获得的MCNO薄膜结晶质量最佳。同时,拉曼光谱测试也表明该MCNO薄膜表现出最强的Mn⁴⁺—O对称弯曲振动和最小的压应力。紫外-可见-近红外光谱分析表明,MCNO薄膜的吸光范围主要在可见光-近红外波段,在80~90 W溅射功率下获得的MCNO薄膜在近红外波段表现出更强的吸收峰。射频溅射功率的改变会影响薄膜的厚度和结晶质量,从而对薄膜的光学带隙起到调控作用。光致发光光谱测试不同溅射功率下薄膜的缺陷峰发光强度,且在功率为80 W时沉积的薄膜具有最强紫外发射峰,表明改变溅射功率能够有效改善薄膜缺陷及提高晶体质量。     

碱金属掺杂ZnO薄膜发光性能研究

采用固相反应法制备了不同比例的碱金属掺杂ZnO靶材,并利用磁控溅射法在Si(111)基片上制备不同温度下生长的c轴择优取向ZnO薄膜.通过XRD、AFM和荧光光谱(PL谱)研究了掺杂元素和掺杂比例对薄膜结构和发光特性的影响.结果表明,掺杂未改变ZnO的结构,薄膜具有很好的c轴择优取向.室温下用325 nm的氙灯作为激发光源得到不同样品的 PL 谱,分析表明,紫外发光峰来源于自由激子的复合辐射与带间跃迁,蓝绿发光峰与锌缺陷和氧缺陷有关.此外还探讨了紫外发光峰红移的可能机理.     

ITO玻璃衬底上生长的Zn0.9Mg0.1S多晶薄膜特性研究

以ZnS和Mg粉末为原料,采用真空蒸镀技术在ITO玻璃上成功地制备了宽禁带三元化合物Zn0.9Mg0.1S多晶薄膜.原子力显微镜和X射线衍射研究表明:薄膜生长形貌和结晶性能良好,为择优取向的立方闪锌矿结构,晶粒直径约20nm,薄膜的X射线衍射峰较之ZnS的衍射峰向大角度方向移动了0.46°;室温下的拉曼谱峰相对于ZnS的拉曼谱峰出现蓝移,且347.67cm-1谱峰比较强;光致发光谱显示,Zn0.9Mg0.1S薄膜在410nm处有一个较强的发光峰.良好的结晶质量和发光特性为开发多功能材料和器件提供了可能性.     

Optical properties of Al‐doped ZnO thin films deposited by two different sputtering methods

Aluminum‐doped zinc oxide (AZO) thin films were deposited on sapphire (002) and glass substrates by two different sputtering techniques radio frequency magnetron cosputtering of AZO and ZnO targets and sputtering of an AZO target. The dependence of the photoluminescence (PL) and transmittance properties of the AZO films deposited by cosputtering and sputtering on the AZO/ZnO target power ratio, R and the O₂/Ar flow ratio, r were investigated, respectively. Only a deep level emission peak appears in the PL spectra of cosputtered AZO films whereas both UV emission and deep level emission peaks are observed in the PL spectra of sputtered AZO films. The absorption edges in the transmittance spectra of the AZO films shift to the lower wavelength region as R and r increase. Also effects of crystallinity, surface roughness, PL on the transmittance of the AZO films were explained using the X‐ray diffraction (XRD), atomic force microscopy (AFM), and PL analysis results. (© 2006 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)     

Sputter power and sputter pressure influenced structural and optical behaviour of RF sputtered nanocrystalline ZnO films

Zinc oxide thin films were deposited on p‐type (100) silicon and Corning glass substrate by using RF magnetron sputtering at different sputter powers range 100–200 W and sputter pressures range 2–8 Pa. The deposited films were characterized by X‐ray diffraction, atomic force microscopy, scanning electron microscopy, Fourier transform infrared spectroscope and UV‐Vis‐NIR spectrophotometer. The films formed at sputter power of 100 W consists of weak (100) reflection and then sputter power increased to 150 W additional (110) reflection was present with enhancement in the intensity of (100) peak. Further increase of sputtering power to 200 W the intensity of (100) phase decreased with the presence of additional peaks of (002) and (101) of ZnO. The FTIR analysis confirms the Zn‐O absorption band was located at 414 cm^‐1. The optical band gap of zinc oxide films decreased from 3.28 to 3.07 eV with increase of sputter power from 100 to 200 W. The maximum crystallite size of 21 nm, the root mean square roughness of 7.2 nm was found at films formed at working pressure of 5 Pa. The optical transmittance of the films increased from 88 to 96% and then decreased to 84% with increase of sputter pressure from 2 to 8 Pa.     

Grain boundary defects induced room temperature ferromagnetism in V doped ZnO thin films

Vanadium (V) doped ZnO thin films (Zn_1‐xV_x O, where x = 0, 0.05, 0.10) have been grown on sapphire substrates by RF magnetron sputtering to realize room temperature ferromagnetism (RTFM). The grown films have been subjected to X‐ray diffraction (XRD), resonant Raman scattering, photoluminescence (PL) and vibrating sample magnetometer (VSM) measurements to investigate their structural, optical and magnetic properties, respectively. The full width at half maximum of XRD and Raman scattering peaks increases with V ion concentration indicates that the V ions have been substituted on Zn²⁺ ions in the ZnO matrix. The increase in oxygen vacancies with V concentration is evidenced by PL measurements. Rutherford backscattering spectrometry analysis confirms the presence of the V ions in the films. The room temperature VSM measurements reveal the signature of ferromagnetism in V doped ZnO thin films. It has been observed that the grain boundary defects, i.e., oxygen vacancies play a crucial role in inducing RTFM in V doped ZnO films. (© 2011 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)     

Mg掺杂ZnO薄膜的结构和光致发光性能的变化

为深入了解ZnMgO合金薄膜的结构与发光性能的关系,采用ZnO和MgO粉末球磨、冷压成型后再高温烧结的方式制靶,在石英基底上室温射频磁控溅射制备了Mg含量0%～8% (原子数分数) 的ZnMgO薄膜,然后于400 ℃空气退火。采用X射线衍射仪表征薄膜的晶体结构,场发射扫描电子显微镜及附带的X射线能谱仪(EDS)观测薄膜颗粒形貌和化学成分,荧光分光光度计测试光致发光(PL)谱。结果发现:ZnMgO合金膜为纤锌矿hcp结构的固溶体,随Mg含量增加,形貌由近似圆形变为圆形和无规则多边形混合型,原因是(002)晶厚失去主导且长大速率被(101)和(110)超过;PL谱出现一个强的紫光峰(390～393 nm)和一个微弱的近红外峰(758～765 nm);随Mg含量的增加,紫光峰位先蓝移后红移,近红外峰位则发生红移;400 ℃空气退火后,所有峰位红移,强度显著增大。对退火处理前后出现的紫光峰和近红外峰的来源和变化规律进行了机制探讨。     

Influence of substrate and film thickness on structural,optical and electrical properties of ZnO thin films

Transparent Zinc Oxide (ZnO) thin films have been grown on Si (100) and Sapphire (0001) substrates by RF magnetron sputtering for different growth time intervals (10, 30 and 60 min) to study the substrate and thickness effects. All the films have been grown at a substrate temperature of 450 °C. It has been found that the average growth rate on Si (100) substrate (8.6 nm/min) is higher than that on Sapphire (0001) substrate (2.6 nm/min) in an identical growth condition which clearly shows the virtual role of substrates. The lower growth rate on Sapphire (0001) suggests that the increasingly ordered and uniform growth due to less lattice mismatch. The grown films have been characterized by X‐ray diffraction (XRD), Reflectance, Photoluminescence (PL) and Hall measurements. The XRD result (FWHM) reveals that for lower growth time, the films grown on Si (100) is better than on Sapphire (0001). Conversely, for higher growth time, the films grown on Sapphire (0001) is better than on Si (100). The variation of strain behavior due to thickness on both substrates has been justified by UV‐Vis reflectance, photoluminescence and Hall effect measurements. (© 2011 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)