Enhanced photoluminescence properties of Cu-doped ZnO thin films deposited by simultaneous RF and DC magnetron sputtering

Copper (Cu)-doped ZnO thin films were grown on unheated glass substrates at various doping concentrations of Cu (0, 5.1, 6.2 and 7.5 at%) by simultaneous RF and DC magnetron sputtering technique. The influence of Cu atomic concentration on structural, electrical and optical properties of ZnO films was discussed in detail. Elemental composition from EDAX analysis confirmed the presence of Cu as a doping material in ZnO host lattice. XRD patterns show that the films were polycrystalline in nature with (002) as a predominant reflection of ZnO exhibited hexagonal wurtzite structure toward c-axis. From AFM analysis, films displayed needle-like shaped grains throughout the substrate surface. The electrical resistivity was found to be increased with increase of Cu content from 0 to 7.5 at%. Films have shown an average optical transmittance about 80% in the visible region and decreased optical band gap values from 3.2 to 3.01 eV with increasing of Cu doping content from 0 to 7.5 at% respectively. Furthermore, remarkably enhanced photoluminescence (PL) properties have been observed with prominent violet emission band corresponding to 3.06 eV (405 nm) in the visible region through the increase of Cu doping content in ZnO host lattice.     

Sn掺杂量对Sn-Al共掺ZnO薄膜光学性能的影响

利用溶胶-凝胶(sol-gel)法在玻璃和硅衬底上制备了不同Sn掺杂量的Sn-Al共掺的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)、光致发光谱(PL)等测试手段,对薄膜的结构、形貌和光学性能进行了表征。结果表明:所制备的样品晶粒均沿(002)方向择优生长,且随着Sn元素掺杂量的增加,择优取向性先增强后减弱,同时薄膜的半高宽先减小后增大,半高宽最小时,薄膜的结晶质量最好。与只掺Al元素的ZnO薄膜相比,共掺后的薄膜近紫外发光峰的强度明显降低,出现了轻微的蓝移,且在600 nm处的缺陷发光强度明显增强;随着Sn掺杂量的增加薄膜的透过率先增加后减小。与AZO薄膜相比,当Sn的掺杂量为0.020时,薄膜的结晶质量更好,缺陷发光更强,光透过率更高。     

溶胶-凝胶旋涂法制备In掺杂ZnO薄膜结构和光学性能的研究

采用溶胶-凝胶(sol-gel)旋涂法在常规玻璃衬底 上生长了In掺杂浓度分别为1at%、2at%、3at%、4at%、5at%的ZnO薄膜。借助X射线衍射仪(X RD)、扫描电子显微镜(SEM)、紫外- 可见分光光度计(UV-Vis)对样品的晶粒生长、结构以及光学性能进行表征。结果如下:所 制 备的薄膜均沿(002)方向择优生长,且随着In³⁺掺杂浓度增加 ,衍射峰的峰型及半高宽均呈 先降低后升高的趋势;In³⁺掺入后,ZnO薄膜晶粒由原来的六边形状发展成类似蠕虫 状,同 时粒径变小且大小不一;与本征样品相比,掺杂后的ZnO光透过率提高了10%,且吸收边向短 波长方向偏移,同时随着In³⁺的掺入,薄膜的光学带隙值从3.49 eV增加到3.80 eV。当In³⁺掺 杂浓度为4at%时,薄膜(002)峰的峰形最为尖锐、峰值最大,晶粒较为均匀、 晶格间距更小,光透过率最高,光学带隙值相对较大为3.77 eV。     

Stability and morphology-dependence of Sc3+ ions incorporation and substitution kinetics within ZnO host lattice

In this study, sol–gel spin coating route was carried out to prepare Scandium doped ZnO thin films with different controlled percentage (1–7%). Particularly, it has been demonstrated, through original conjoint morphological-structural and optical investigations, that some interesting physical properties were induced. Indeed, X-ray diffraction (XRD) analysis shows that (002) preferential crystalline plane for Sc doped ZnO films was kept along with ZnO hexagonal würtzite structure, although Sc doping seemed to cause a decrease in crystallinity. Except for 1 at% Sc doping ratio, optical band gap changes reversely with Urbach energy with a decrease in optical gap and a broadening of the absorption tail. Ab-initio calculations of lattice dynamical properties outlined additional strong hybridization between Sc and O atoms and show the stability of Scandium doped ZnO.     

Li掺杂量对Li-N共掺ZnO薄膜光学性能的影响

本文利用溶胶-凝胶旋涂法在玻璃衬底上制备了 本征、N单掺和Li-N共掺的ZnO薄膜。 研究Li掺杂量的改变对薄膜的晶体结构、表面形貌、透过性能和发光性能的影响。采用了紫 外-可见分光光度计(UV-VIS)、光致发光谱(PL)、扫描电子显微镜(SEM)和X射线衍 射 仪(XRD)等表征手段对样品进行了测试。结果表明:Li掺杂量的改变对薄膜的结构和性能 都有一定的影响,随着Li掺杂量的增加,(002)衍射峰强度增大,晶 粒尺寸先增加后减小, 紫外发射峰的强度和薄膜的透过性能同样是先增强后减弱。当Li元素的原子比为6at%时, 薄膜的c轴择优取向明显,结晶性能最好,薄膜紫外发光最强,透过率最大。     

sol-gel法制备ZAO薄膜的结构与光学性能研究

采用溶胶—凝胶法在普通玻璃衬底上制备了ZAO(ZnO:A1)薄膜,利用XRD、SEM、紫外—可见光谱和光致发光光谱对所制备的AZO薄膜进行了表征,研究了ZAO薄膜的结构和光学性能.结果表明:ZAO薄膜的微晶晶相与ZnO一致,且具有c轴择优取向;ZAO薄膜在可见光区的透过率超过了88％,在350～575 nm范围内有强的...     

梯度掺杂生长绒面结构ZnO:B-TCO薄膜及其特性研究

采用新的金属有机化学气相淀积(MOCVD)-ZnO镀膜工艺技术-梯度掺杂技术生长绒面结构。研究ZnO:B-TCO薄膜。结果表明,梯度掺杂技术可有效增加薄膜晶粒尺寸和提高光散射作用。并且,梯度掺杂技术有效地提高了薄膜在近红外区域的光学透过率,有利于应用于宽谱域薄膜太阳电池。生长获得的MOCVD-ZnO薄膜,其薄膜电子迁移率为24 cm2/V,电阻率为2.17×10-3Ω.cm,载流子浓度为1.20×1020cm-3,且在小于1 000 nm波长范围内的平均透过率大于85%。     

ZnO薄膜的结构与光学性能研究

采用sol-gel法在石英衬底上制备了ZnO薄膜,通过改变溶胶浓度、涂敷层数及退火温度,研究了ZnO薄膜的形貌、结构性能及光学性能。结果表明,薄膜具有六方纤锌矿结构,表面均匀致密,晶粒大小在25～35nm之间,Zn含量为0.8mol/L的溶胶经旋涂并在500℃下退火1h后可获得最高的可见光透射率,平均透射率约为94%。获得的ZnO薄膜的光学带隙在3.27～3.29eV之间。     

Spray deposited ZnO and Ga doped ZnO based DSSC with bromophenol blue dye as sensitizer: Efficiency analysis through DFT approach

Dye sensitized solar cells based on spray deposited ZnO and Ga doped ZnO (GZO) thin film were fabricated with Bromophenol Blue as the photo sensitizer. XRD results show the hexagonal wurtzite phase of ZnO and GZO thin films with c-axis growth orientation, and the diminished crystalline nature of GZO thin film as the effect of doping. FE-SEM results revealed the morphology induced internal light interaction capability of GZO thin film for better harvesting of photon energy. Photovoltaic studies showed that the DSSC fabricated with GZO thin film has obtained enhanced power conversion efficiency (1%) than the ZnO thin film based DSSC (0.2%), as a result of Ga doping. To investigate the obtained photovoltaic performance of the device, the electronic properties of Bromophenol Blue dye were theoretically analyzed with Density Functional Theory (DFT) study.     

PLD法制备ZnO薄膜的退火特性和蓝光机制研究

通过脉冲激光沉积(PLD)方法,在O2中和100～500℃衬底温度下,用粉末靶在Si(111)衬底上制备了ZnO薄膜,在300℃温度下生长的薄膜在400～800℃温度和N2氛围中进行了退火处理,用X射线衍射(XRD)谱、原子力显微镜(AFM)和光致发光(PL)谱表征薄膜的结构和光学特性。XRD谱显示,在生长温度300℃时获得较好的复晶薄膜,在退火温度700℃时获得最好的六方结构的结晶薄膜;AFM显示,在此退火条件下,薄膜表面平整、晶粒均匀;PL谱结果显示,在700℃退火时有最好的光学特性。     

Multifunctional device based on ZnO:Fe nanostructured films with enhanced UV and ultra-fast ethanol vapour sensing

Extensive application requests on high-performance gas sensors and photodetectors reveal the importance of controlling semiconducting oxide properties. Sensing properties of ZnO nano- and micro-structures can be tuned and their functional performances can be enhanced more efficiently by metal-doping. Here, we report the synthesis of crystalline Fe-doped ZnO (ZnO:Fe) nanostructured films via a cost-effective and simple synthesis from chemical solutions (SCS) approach followed by rapid thermal annealing (RTA) with excellent potential for the development of multifunctional devices for UV and ethanol (C₂H₅OH) vapour sensing. The effects of two types of thermal annealing on the ZnO:Fe morphology, the crystallinity, the electronic and the vibrational properties, the UV radiation and the gas sensing properties are investigated. The experimental results indicate an increase in UV response (I_UV/I_DARK~10⁷) of as-grown ZnO nanostructured films by Fe-doping, as well as an essential improvement in rise and decay times due to RTA effects at 725 °C for 60 s. In comparison with un-doped samples, ZnO:Fe (0.24 at%) specimens showed a response to ethanol which is enhanced by a factor of two, R_air/R_gas~61. It was demonstrated that by using Fe-doping of ZnO it is possible to reduce essentially the response τ_r and recovery times τ_d of the multifunctional device. The involved gas sensing mechanism is discussed in detail in this paper. The presented results could be of great importance for the application of RTA and doping effects for further enhancement of UV detection and gas sensing performances of the ZnO:Fe nanomaterial-based multifunctional device.     

Synthesis of highly selective and sensitive Cu-doped ZnO thin film sensor for detection of H2S gas

Copper (Cu) doped zinc oxide (ZnO) thin films were successfully prepared by a simple sol-gel spin coating technique. The effect of Cu doping on the structural, morphology, compositional, microstructural, optical, electrical and H₂S gas sensing properties of the films were investigated by using XRD, FESEM, EDS, FTIR, XPS, Raman, HRTEM, and UV–vis techniques. XRD analysis shows that the films are nanocrystalline zinc oxide with the hexagonal wurtzite structure and FESEM result shows a porous structured morphology. The gas response of Cu-doped ZnO thin films was measured by the variation in the electrical resistance of the film, in the absence and presence of H₂S gas. The gas response in relation to operating temperature, Cu doping concentration, and the H₂S gas concentration has been systematically investigated. The maximum H₂S gas response was achieved for 3 at% Cu-doped ZnO thin film for 50 ppm gas concentration, at 250 °C operating temperature.     

RF反应磁控溅射纳米晶ZnO薄膜的XRD和XPS研究

采用RF反应磁控溅射沉积ZnO薄膜,沉积完成后对薄膜进行氧气氛下的原位退火处理。薄膜的结晶状况和化学成分分别采用XRD和XPS进行分析。结果表明,该薄膜为结晶性能良好的纳米晶薄膜,具有高度的C轴取向性。薄膜的主要成分为ZnO,不存在金属态Zn。采用文中的工艺方法可获得较高质量的纳米晶ZnO薄膜。     

Enhancement of optical and electrical properties of SILAR deposited ZnO thin films through fluorine doping and vacuum annealing for photovoltaic applications

Undoped and fluorine doped ZnO thin films were deposited onto glass substrates using successive ionic layer adsorption and reaction (SILAR) technique and then annealed at 350 °C in vacuum ambience. The F doping level was varied from 0 to 15 at% in steps of 5 at%. The XRD analysis showed that all the films are polycrystalline with hexagonal wurtzite structure and preferentially oriented along the (002) plane. Crystallite sizes were found to increase when 5 at% of F is doped and then decreased with further doping. It was seen from the SEM images that the doping causes remarkable changes in the surface morphology and the annealing treatment results in well-defined grains with an improvement in the grain size irrespective of doping level. All the films exhibit good transparency (>70%) after vacuum annealing. Electrical resistivity of the film was found to be minimum (1.32×10⁻³ Ω cm) when the fluorine doping level was 5 at%.     

Characterization of electron beam evaporated ZnO thin films and stacking ZnO fabricated by e-beam evaporation and rf magnetron sputtering for the realization of resonators

High quality Zinc oxide thin films have been fabricated by reactive e-beam evaporation in an oxygen environment. The effect of air annealing on the optical and structural properties of the e-beam evaporated ZnO is investigated. Raman spectroscopy has been found to be an efficient tool to evaluate the residual stress in the as-grown ZnO films from the position of the E₂ (high) mode. Photoluminescence and transmittance measurements showed that the best optical and structural quality of the e-beam evaporated ZnO occurred at 300 °C. Finally, thin films of ZnO evaporated by e-beam technique have served to eliminate the compressive stress due to the sputtered piezoelectric ZnO and therefore to improve the quality of the fabricated resonators by stacking these ZnO layers fabricated by electron beam technique and rf magnetron sputtering, respectively.     

溶胶-凝胶法制备Al3+掺杂ZnO薄膜的结构和光学性能

采用无机盐溶胶-凝胶方法在载玻片衬底上制备了ZnO:Al薄膜,利用X射线衍射(XRD)、紫外-可见光透射光谱(UV-Vis transmittance spectrum)和扫描电镜(SEM)研究了退火温度和Al3+掺杂浓度对ZnO:Al薄膜结构和光学性能的影响.结果表明,随退火温度的升高或进行适当浓度的Al3+掺杂,可...     

Epitaxial growth of ZnO on GaN/sapphire substrate by radio-frequency magnetron sputtering

Zinc oxide (ZnO) thin films were grown on n-GaN/sapphire substrates by radio-frequency (RF) magnetron sputtering. The films were grown at substrate temperatures ranging from 400 to 700 ℃ for 1 h at a RF power of 80 W in pure Ar gas ambient. The effect of the substrate temperature on the structural and optical properties of these films was investigated by X-ray diffraction (XRD), atomic force microscopy (AFM) and photoluminescence (PL) spectra. XRD results indicated that ZnO films exhibited wurtzite symmetry and c-axis orientation when grown epitaxially on n-GaN/sapphire. The best crystalline quality of the ZnO film is obtained at a growth temperature of 600 ℃. AFM results indicate that the growth mode and degree of epitaxy strongly depend on the substrate temperature. In PL measurement, the intensity of ultraviolet emission increased initially with the rise of the substrate temperature, and then decreased with the temperature. The highest UV intensity is obtained for the film grown at 600 ℃ with best crystallization.     

ZAO膜磁控溅射变参数制备技术

采用射频磁控溅射技术生长ZnO:Al(ZAO)薄膜,用X射线衍射仪检测薄膜的结晶质量。为了提高薄膜的生长效率,进行了在生长过程中调整生长参数的试验。结果发现,生长过程中适当地改变参数,不仅可以提高薄膜的生长效率,还可以获得结晶质量更好的薄膜。在工作压强0.35Pa、溅射功率120W条件下粗生长后,改变工作压强为0.2Pa、溅射功率80W进行细生长,制得的薄膜平均可见光透射率为88%,电阻率为7.8×10–4Ω·cm。     

Properties of antimony doped ZnO thin films deposited by spray pyrolysis technique

Antimony (Sb) doped zinc oxide (ZnO) thin films were deposited on the glass substrate at 450°C using spray pyrolysis technique. Effect of Sb doping on surface morphology structural, optical and electrical properties were studied. X-ray diffraction (XRD) analysis showed that both the undoped and doped ZnO thin films are polycrystalline in nature with (101) preferred orientation. SEM analysis showed a change in surface morphology of Sb doped ZnO thin films. Doping results in a marked increase in conductivity without affecting the transmittance of the films. ZnO films prepared with 3 at % Sb shows the lowest resistivity of 0.185 Ohm cm with a Hall mobility of 54.05 cm² V^–1 s^–1, and a hole concentration of 6.25 × 10¹⁷ cm^–3.     

Evaluation of an Nd doping effect on characteristic properties of tin oxide

In the present work, transparent and conductive Nd doped SnO₂ thin films were deposited via spray pyrolysis. Crystallographic, morphological, optical and electrical characterizations of SnO₂ were researched as a function of Nd doping. The XRD analysis indicated the films had tetragonal cassiterite tin oxide structure and (211) preferential direction for NdTO-0, NdTO-1, NdTO-2 and NdTO-3 samples changed to (110) plane for NdTO-4 and NdTO-5 samples. The crystalline size and strain analysis were made by using a Williamson–Hall method. The SEM micrographs showed that all films had homogenously scattered pyramidal and small densely nanoparticles. The optical analysis indicated optical band gap value of undoped film increased with 1 at% Nd doping and then it decreased with more Nd content. The Hall measurements indicated that the highest electrical conductivity was obtained for 2 at% Nd doping content.