室温无反应磁控溅射法制备ZAO导电薄膜及其特性研究

以氧化铝(Al2O3)掺杂的ZnO陶瓷靶材为基础,室温下采用无氧直流磁控溅射法在载玻片衬底上制备了ZnO∶Al(ZAO)透明导电薄膜,研究了不同的Al2O3掺杂量对薄膜微观结构、电阻率和透光率性能的影响。结果表明:掺杂量大于1%(质量分数,下同)的薄膜均呈c轴择优取向生长,薄膜致密无裂纹,具有光滑表面;掺杂量对薄膜的电阻率影响显著,当掺杂量为3%时,薄膜的电阻率最小,仅为7.4×10-3Ω.cm;掺杂量对薄膜的透光性无明显影响,不同掺杂量的薄膜在可见光区的平均透光率接近90%。     

ZAO特性及其在CIGS电池中的应用

透明导电氧化物薄膜(Transparent Conductive Oxides,简称TCO)用途广泛,介绍了TCO应用于光伏领域中的铜铟镓硒薄膜(CIGS)太阳电池,是CIGS太阳电池中不可缺少的一部分。简要阐述了其可见光范围内的透明性和导电性及其成因,以及作为CIGS薄膜太阳电池中窗口层的作用。将ITO和ZAO透明导电薄膜在CIGS太阳电池的应用进行相比,以掺铝的氧化锌(ZnO∶Al简称ZAO)透明导电薄膜为例,对其性能、制备方法及过程进行了简要阐述,并概括了大面积ZAO薄膜的性能。     

溶胶-凝胶法制备ZAO透明导电氧化物薄膜的研究进展

溶胶-凝胶法是一种高效的制膜技术。本文综述了溶胶-凝胶法制备氧化锌铝(ZAO)透明导电氧化物薄膜(TCO)的原理、特点及研究进展,指出了采用溶胶-凝胶法制备ZAO薄膜今后急需解决的问题。     

过渡族金属掺杂ZnO薄膜的晶体结构和磁性能

采用电子束蒸发法制备了过渡族金属(Fe、Co、Cu)掺杂ZnO薄膜。分析和研究了衬底温度以及Cu掺杂量对薄膜相结构的影响,获得沿c轴高度择尤取向的高质量ZnO薄膜。采用原子力显微镜(AFM)观察薄膜的显微结构,利用所得的图象信息对薄膜进行分析,发现400℃的衬底温度对硅衬底薄膜是合适的,与XRD分析相吻合。通过对薄膜磁性能的分析和研究,得出一些有意义的结果:适量Fe、Co离子掺杂的ZnO薄膜,在室温下具有铁磁性,而在此基础上掺入少量的Cu离子能改善薄膜的磁性能。     

真空热蒸发制备ZnS薄膜及其特性的研究

用真空热蒸发在不同衬底温度下制备了ZnS薄膜,利用X射线衍射(XRD)、X射线能谱(EDAX)、紫外可见分光光度计(UV-vis)和原子力显微镜(AFM)研究了ZnS薄膜的晶体结构、成分、光学性能和形貌,分析了衬底温度对ZnS薄膜结构与光学特性的影响。结果表明,所制备的ZnS薄膜呈立方闪锌矿结构,衬底温度为300℃所制备的ZnS薄膜原子比(S/Zn)为0.95/1;薄膜表面均匀致密,呈多晶态,晶粒尺寸为18.2nm;在可见区有好的透射性能,光学禁带宽度为3.82eV。     

Fe:SmCo(Cr)薄膜的结构、磁性能与磁光克尔效应

利用脉冲激光沉积工艺,分别在单晶Si(100)衬底和玻璃(Si O2)衬底上制备Fe:Sm Co/Cu(Cr)薄膜,研究了Fe掺杂对Sm Co薄膜结构、磁性能与磁光效应的影响。实验发现,衬底对Fe掺杂Sm Co薄膜性能有很大影响,Si衬底薄膜的矫顽力和饱和磁化强度均优于玻璃衬底样品;同时退火温度也会影响Fe掺杂Sm Co薄膜形貌及磁性能,高温退火后,Sm Co衍射峰得到了增强,尤其是Sm Co5的(001)、(002)和(003)衍射峰最为明显,这是由于高温退火后Cu(111)衍射峰增强的缘故。同时发现,退火后的Si O2衬底与Si衬底样品的磁性和磁光效应均得到增强,但Si O2衬底的矫顽力Hc变化更明显,这是因为较高的表面应力会导致样品的矫顽力增强。因此可以通过调节Fe含量来控制样品的磁光性能,这就为优化Sm Co薄膜作为磁光存储介质的性能指出了一个研究方向。     

溶胶-凝胶法制备ZAO透明导电氧化物薄膜的研究进展

溶胶-凝胶法是一种高效的制膜技术。本文综述了溶胶-凝胶法制备氧化锌铝（ZAO）透明导电氧化物薄膜（TCO）的原理、特点及研究进展,指出了采用溶胶-凝胶法制备ZAO薄膜今后急需解决的问题。     

Zn1-xMgxO薄膜中缺陷诱导的室温铁磁性

采用脉冲激光沉积( PLD)方法在单晶Si(100)衬底上制备2n1 -xMgxO(x=0.075,0.15,0.35,0.65)薄膜,研究了不同Mg含量掺杂、氧压、退火温度对其磁性的影响.分析表明,Mg掺杂量会影响薄膜中的缺陷浓度,进而影响缺陷周围离子中的自旋极化效应,对薄膜磁性产生影响.氧压的增大会使Zn0.925...     

ZnO基紫外光透明导电薄膜的研究进展

ZnO是一种宽禁带半导体材料,通过阳离子Al^3＋掺杂可以改善其导电性,而且通过掺杂MgO进行“能带剪裁”可以实现从紫外到可见光范围内的完全透明。因此,ZnO基紫外光透明导电薄膜近年来逐渐成为半导体光电材料与器件的研究热点之一。本文介绍了紫外光透明导电薄膜MgxZn1-xO：Al的基本特性、制备方法及研究进展。     

Mo衬底厚度对Ni-Mn-Ga形状记忆合金薄膜形貌及磁性能的影响

采用射频磁控溅射法制备不同厚度Mo衬底的Ni-Mn-Ga薄膜,采用扫描电子显微镜(FE-SEM)、原子力显微镜(AFM)、磁力显微镜(MFM)、振动样品磁强计(VSM)以及X射线衍射仪(XRD)对其形貌及磁性能进行观测和分析。实验发现,制备的Mo衬底Ni-Mn-Ga薄膜经退火后为T型马氏体结构,且当Mo衬底厚度在0~200 nm范围内变化时,其饱和磁化强度及居里温度呈现先减小后增大的趋势。当Mo衬底厚度约为100 nm时饱和磁化强度和居里温度具有最低值。薄膜表面颗粒直径随着Mo厚度的增大而减小,但在Mo厚为100 nm时出现增大。     

Characterization of the CeO2 thin films for insulation layer and Pt/SrBi2Ta2O9/CeO2/Si MFISFET structure

Abstract

CeO₂ and SrBi₂Ta₂O₉ (SBT) thin films for MFISFET (metal-fcrroelectrics-insulator-semiconductor field effect transistor) were deposited by rf sputtering and pulsed laser deposition method, respectively. The effects of oxygen partial pressure during deposition for CeO₂ films were investigated. The oxygen partial pressure significantly affected the preferred orientation, grain size and electrical properties of CeO₂ films. The CeO₂ thin films with a (200) preferred orientation were deposited on Si(100) substrates at 600°C. The films deposited under the oxygen partial pressure of 50 % showed the best C-V characteristics among those under various conditions. The leakage current density of films showed order of the 10^?7～10^?8 A/cm² at 100 kV/cm. The SBT thin films on CeO₂/Si substrate showed dense microstructure of polycrystalline phase. From the C-V characteristics of MFIS structure composed of the SBT film annealed at 800°C, the memory window width was 0.9 V at ±5 V. The leakage current density of Pt/SBT/CeO₂/Si structure annealed at 800°C was 4×10^?7 A/cm² at 5 V.     

Effects of sputtering pressure and thickness on properties of ZnO:Al films deposited on polymer substrates

Highly conducting and transparent aluminum doped zinc oxide (ZnO:Al) thin films have been deposited on polyimide substrate by r.f. magnetron sputtering at room temperature. The influence of sputter pressure and thickness on the structural, electrical, and optical properties of ZnO:Al films deposited on polyimide substrate is reported. The crystallinity and degree of orientation was increased by decreasing the sputter pressure. For higher sputtering pressures an increase on the resistivity was observed due to a decrease on the mobility and the carrier concentration. As the film thickness was increased, the crystallite sizes were increased, but the average transmittance in the wavelength range of the visible spectrum was decreased. The electrical performances of the ZnO:Al films deposited on glass substrates are slightly worse than the ones of the films deposited on polyimide substrates with same thickness. The lowest resistivity of 8.6?×?10^?4 Ω cm can be obtained for films deposited on glass substrate with the thickness of 800 nm.     

Study on the electrical and optical properties of ITO and AZO thin film by oxygen gas flow rate

Transparent conductive oxide (TCO) thin films such as tin doped indium oxide (ITO), zinc doped indium oxide (IZO) and Al doped zinc oxide (AZO) have been widely used as transparent electrode for display. ITO and AZO thin films for display was prepared by the facing targets sputtering (FTS) system. The FTS method is called a plasma-free sputter method because the substrate is located apart from plasma. This system can deposit the thin film with low bombardment by high energetic particles in plasma such as γ-electrons, negative ions and reflected Ar atoms. ITO and AZO thin films were deposited on glass substrate at room temperature with oxygen gas flow rate and input power. And the electrical, structural and optical properties of the thin films were investigated. As a result, the resistivity of ITO, AZO thin film is 6?×?10^?4 Ω cm, 1?×?10^?3 Ω cm, respectively. And the optical transmittance of as-deposited thin films is over 80% at visible range.     

Growth and Studies of Calcium Doped Laser Ablated Barium Titanate Thin Films

Ba_{1 ? x}Ca_xTiO₃ targets were prepared by conventional solid state reaction with varied amounts of the calcium content (5 at.%, 10 at.%) and the thin films were deposited on Pt(111) coated Si substrate using pulsed laser ablation technique. The thin films were deposited at different pressures and temperatures, so as to determine the optimized growth parameter for the good quality BCT thin films. The pressure variation on the growth parameters made a dramatic impact in tailoring the dielectric constant and phase transition. The phase evolution of the BCT thin films evolves from 450°C and at higher substrate temperatures (～700°C) for different partial pressures of oxygen, the preferred orientation of the thin films were observed. The SIMS analysis reveals a sharp interface exist at the bottom electrode (Pt)–BCT thin films indicating no interdiffusion taking place which might lead to the degradation of devices. The BCT thin films deposited at higher pressures (>60 mtorr) exhibited higher Ba content indicating the possibility of the Ca occupying the Ti site and is reflected in the decrease of the dielectric phase transition temperature. The ferroelectric hysteresis and Capacitance voltage measurement shows the signature of ferroelectricity.     

脉冲激光沉积(PLD)法制备NiZn铁氧体多晶薄膜研究

采用脉冲激光沉积（PLD）法分别在硅和玻璃基片上沉积了NiZn铁氧体多晶薄膜。实验表明：基片温度、氧气压以及热处理对薄膜的沉积速率、磁性能有很大影响。     

Studies on Laser Ablated SrBi 2 Ta 2 O 9 and Sr 0.8 Ca 0.2 Bi 2 Ta 2 O 9 Ferroelectric Thin Films

Ferroelectric thin films of SrBi 2 Ta 2 O 9 (SBT) and (Sr 0.8 Ca 0.2 )Bi 2 Ta 2 O 9 (SCBT) were grown on platinized silicon substrates by using pulsed laser deposition technique. The effect of annealing temperature on the structural and electrical properties of the films was studied. Films were grown at 200 mTorr oxygen pressure with a constant substrate temperature at 500°C and annealed at different temperatures ranging from 700-800 °C in an oxygen ambient. X-ray diffraction data showed that as-grown films were crystalline nature. Atomic force micrographs showed that the grain size and surface roughness increased with increase in annealing temperature. The SBT films annealed at 800 °C showed ferroelectric properties with remanent polarization of 9.1 w C/cm 2 and coercive field of nearly 72 kV/cm. Whereas the SCBT films showed maximum remanent polarization of 7.3 w C/cm 2 with higher coercive field of 86 kV/cm. The higher coercive field in case of SCBT is attributed to the higher electronegativity of partially substituted Ca at Sr site. The dielectric constant increased with increase in annealing temperature and was attributed to the higher grain size.     

Optical properties of RF-sputtered Ba0.65Sr0.35TiO3 thin films

Ba_0.65Sr_0.35TiO₃ (BST) thin films have been prepared by radio frequency magnetron sputtering on fused quartz at different substrate temperatures. Optical constants (refractive index n, extinction coefficient k) were determined from the optical transmittance spectra using the envelope method. The dispersion relationship of the refractive index vs. substrate temperature was also investigated. The refractive index of BST thin films increased from 1.778 to 1.961 (at λ?=?650 nm) as deposited temperature increases from 560°C to 650°C. The extinction coefficient of as-deposited BST thin films increased with the increase of the oxygen-to-argon ratio, which was due to the change of the film stoichiometry, structure, and texture of BST thin films. The oxygen-to-argon ratio also affected the fluorescence spectra. The fluorescence peaks intensity was greatly increased, apparent frequency shift was detected, and the linewidth became narrow as the ratio of oxygen to argon increased from 1:4 to 1:1. The fluorescence spectra also indicated the band transition of BST thin films was an indirect gap transition.     

Tailoring the structural and optical properties of RF magnetron sputtered ZnO/graphene thin films by annealing temperature

Abstract

ZnO and ZnO/Graphene thin films were deposited on Cu substrate using a low pressure chemical vapor deposition (LPCVD) and the magnetron sputtering method. The impacts of graphene layer growth and annealing temperature on the optical properties ZnO and ZnO/Graphene thin films were investigated by X-ray diffraction (XRD), Raman spectroscopy, scanning electron microscope (SEM), X-ray photoelectron spectroscopic (XPS), and photoluminescence (PL) measurements respectively. XRD and SEM results reveal that all the thin films preferred the crystalline [001] orientation along the c-axis direction, which were vertical grown on substrate surface. By comparing the results and analysis of their structure, morphology, chemical bonding and optical property, it is proved that using Graphene as a buffer layer can improve the crystal quality of ZnO thin films. For the annealed ZnO/graphene nanostructures, the area ratio of UV and visible emission region of ZnO/graphene thin films increase with increasing the annealing temperature, reaches a maximum at 500?°C and then starts decreasing with further increase in annealing temperature, which indicating that the controllable ZnO/Graphene thin films have the higher crystallization quality at the annealing temperature of 500?°C. Our results demonstrate that for high quality ZnO/graphene thin films deposition, decreasing the defect concentration should be preferable to simply applying the proper annealing temperature, which might have promising applications for various UV photodetectors devices.     

Phase evolution and Sn-substitution in LiMn2O4 thin films prepared by pulsed laser deposition

LiMn₂O₄ thin films prepared on a Pt/Ti/SiO₂/Si(100) substrate by pulsed laser deposition were studied with focusing on the effects of different processing conditions and Sn substitution on phase evolvement and surface microstructure. Major experimental parameters include substrate temperature up to 770 °C and working oxygen pressure of 50–250 mTorr. LiMn₂O₄ thin films became highly crystallized with increased grain sizes as the substrate temperature increased. Second phases such as LiMnO₂ and Li₂Mn₂O₄ were found at the temperature of 300 and 770 °C, respectively. As an optimum condition, films grown at 450 °C showed a homogeneous spinel phase with well-defined crystallinity and smooth surface. A high pressure of oxygen tended to promote crystallization and grain growth. Working pressure did not affect significantly the phase formation of the thin films except that unexpected LiMn₃O₄ phase formed at the lowest oxygen pressure of 50 mTorr. Tin-substituted thin films showed lower Mn–O stretching vibrations, which suggests that more Li-ions can be inserted into vacant octahedral sites of the spinel structure.     

Dielectric characteristics investigation of (Ba0.7Sr0.3)(Ti0.9Zr0.1)O3 ferroelectric thin films

By the radio frequency (RF) magnetron sputtering methods, (Ba_0.7Sr_0.3)(Ti_0.9Zr_0.1)O₃ (BSTZ) ferroelectric thin films were deposited on the Pt/Ti/SiO₂/Si(100) substrates. The crystal structural and microstructure of these thin films were analyzed by means of the XRD, SEM, and AFM. Moreover, the dielectric characteristics were also investigated by the C-V and J-E analyses. The optimal deposition parameters for these BSTZ thin films were: RF power is 160 W, oxygen concentration is 25%, substrate temperature is 580°C, and chamber pressure is 0.075 mPa. Under these optimal deposition conditions, the (111) and (110) oriented polycrystalline of the BSTZ thin films grow easily. And under a bias voltage of 0.5 MV/cm, the dielectric constant and leakage current density of the BSTZ thin films are 191 and 3×10^?8 A/cm², respectively. In addition, under various measured temperatures (0 ～ 80°C) and frequencies (100 kHz ～ 1 MHz), all the dielectric constants remain almost unchanged. Compared to BSTZ thin films reported previously, in this study, the deposited thin films have the advantage of lower leakage current and hence are suitable for the applications of dynamic random access memory.