Structural and optical investigations at room temperature of sulfurized thermal evaporated Cu2ZnSnS4

Journal of Materials Science: Materials in Electronics - The present work investigates the structural and optical properties of Cu2ZnSnS4 (CZTS) thin films deposited at room temperature with...     

Wide bandgap CIGS thin films via Ag-PDT to ameliorate the interface quality of CIGS/CdS heterojunction

Journal of Materials Science: Materials in Electronics - Wide bandgap Cu(In,Ga)Se2 (CIGS) thin films play an important role in tandem solar cells. However, the wide bandgap CIGS obtained by high...     

Fabrication of CeO2/CuO bimetallic oxides thin film heterostructure for tunable UV filter applications

Journal of Materials Science: Materials in Electronics - In the present study, we report a direct growth of Ce–Cu–O bimetallic oxide-nanostructured thin films deposited onto ITO (Indium...     

Homogeneous and polymorphic transformations to ordered intermetallics in nanostructured Au–Cu multilayer thin films

Journal of Materials Science - Atomic arrangements in the nanostructured grains and interfaces of thermally evaporated Au/Cu multilayer thin films on polycrystalline Si substrate have been explored...     

Formation of vacancy clusters in deformed thin films of Al–Mg and Al–Cu dilute alloys

In the present study, vacancy clusters in elongated Al–Mg and Al–Cu thin films (Mg/Cu CONCENTRATION=0.05–1.70 at.%) were examined by electron microscopy. No dislocations were observed in these films. In Al–Mg thin films deformed at room temperature, a large number of stacking fault tetrahedra (sft) were observed alongside a few vacancy loops. The opposite was true for Al–Cu thin films, where well-grown loops predominated, and only a few sft were observed. The Al–Cu film results show that the majority of vacancies form loops larger than sft. We also deformed Al–0.05at.% (Mg or Cu) alloys in liquid nitrogen and cold-transferred to an electron microscope. In Al–Mg, a large number of dotted defects (possibly sft) were observed, while very few such defects were observed in Al–Cu. This indicates that loops observed in Al–Cu thin films deformed at room temperature, grew during/after deformation. The likely contribution of strain-induced vacancies in deformed Al thin films to the voiding in VLSI interconnect wires due to electro-migration were discussed.     

Thickness dependence of structural, electrical and optical properties of sprayed ZnO:Cu films

ZnO:Cu thin films have been deposited by spray pyrolysis techniques within two different (450 °C and 500 °C) substrate temperatures. The structural properties of ZnO:Cu thin films have been investigated by X-ray diffraction techniques. The X-ray diffraction spectra showed that ZnO:Cu thin films are polycrystalline with the hexagonal structure and show a good c-axis orientation perpendicular to the substrate. The most preferential orientation is along the (002) direction for all spray deposited ZnO:Cu films together with orientations in the (100) and (101) planes also being abundant. Some parameters of the films were calculated and correlated with the film thickness for two different substrate temperatures. The optical properties of ZnO:Cu thin films have been investigated by UV/VIS spectrometer and the band gap values were found to be ranging from 3.29 eV to 3.46 eV.     

Effects of transition metal (Cu,Zn, Mn) doped on leakage current and ferroelectric properties of BiFeO<Subscript>3</Subscript> thin films

BiFeO₃ (BFO) and transition metal (Cu, Zn, Mn) doped BFO thin films were successfully fabricated on indium tin oxide (ITO)/glass substrate using sol–gel process, spin coating and layer by layer technique. Compared to the pure BFO thin film, improved ferroelectric and leakage current properties were observed in the transition metal doped BFO thin films. The transition metal (Cu, Zn, Mn) doped BFO thin films have varying degrees of lower leakage current compared with the pure BFO film. The substitution of Cu and Zn increase the remnant polarization of BFO thin films. The values of remnant polarization (2Pr) were 120.6 and 126.7 μC/cm² at 933 kV/cm for Cu-doped and Zn-doped BFO thin film, respectively.     

氢气与Cu中间层对GZO薄膜光电性能的影响

采用磁控溅射方法, 在H₂/Ar混合气氛下制备了GZO薄膜和在Ar气氛下制备了GZO/Cu/GZO多层结构薄膜, 分别研究了H2流量和Cu层厚度对薄膜透明导电性能的影响。在此基础上, 在H₂/Ar混合气氛下制备了GZO/Cu/GZO多层结构薄膜, 对Cu层厚度对其性能的影响进行了研究。结果表明, 沉积气氛中引入H₂能有效降低GZO薄膜的电阻率而提高其透光率, 在H₂流量为20 sccm时GZO薄膜具有最佳性能。随着Cu厚度的增加, GZO/Cu/GZO多层结构薄膜的电阻率和平均透过率显著下降。在H₂/Ar混合气氛下制备的氢化GZO/Cu/GZO多层结构薄膜的电阻率普遍低于Ar气氛下制备的GZO/Cu/GZO多层结构薄膜, 但其透光率却随Cu层厚度的增加而显著降低。另外, 薄膜的禁带宽度随H₂流量的增加而增加, 随Cu层厚度的增加而减小。     

Influence of concentration and annealing temperature on spin-coated metal oxide thin films for optoelectronic devices

Journal of Materials Science: Materials in Electronics - The metal oxide thin films, such as cadmium oxide (CdO) and zinc oxide (ZnO) thin films, were deposited by sol–gel-derived spin...     

The effect of grain size and film thickness on the thermal expansion coefficient of copper thin films

Cu thin films underwent thermal cycling to determine their coefficient of thermal expansion (CTE). The thermal stress of the Cu thin films with various microstructures (different grain size and film thickness) was measured using a curvature measurement system. The thermal expansion coefficients of the films were obtained from the slope of the stress-temperature curve with the knowledge of the Young's modulus and Poisson's ratio. The change in thermal stress with temperature of the Cu thin films tended to decrease with increasing grain size, resulting in an increase in the CTE. The thickness of Cu thin film had little effect on the thermal stress or the CTE.     

Effect of annealing on the resistivity of quench-condensed Cu and Cu(Fe) thin films

Pure Cu and Cu(Fe) thin films containing 0.1 and 1.0 at % Fe were prepared by low-temperature deposition onto a liquid-helium-cooled substrate. The Cu(Fe) films were annealed sequentially at approximately 17, 70, and 270 K. After each annealing stage the resistivity was measured down to 1.5K. The Cu(Fe) films exhibited a region in which the resistivity was proportional to ln T; in this region the logarithmic slope of the resistivity curve was only weakly affected by annealing. Below 10 K annealing produced a significant decrease in the impurity (Fe) contribution to the resistivity. The results are interpreted as due to increased interactions between Fe atoms produced by an increase in conduction-electron mean free path.This work was supported by the Materials Research Center, University of North Carolina, under Grant Number GH-33632 from the National Science Foundation.     

周期性前驱体的预硫化处理对Cu2ZnSnS4薄膜的影响EI北大核心CSCD

Cu2ZnSnS4薄膜具有组成元素来源丰富、吸收系数高等优点,是理想的薄膜太阳能电池吸收层材料。采用磁控溅射法沉积周期性金属叠层前驱体,再进行两步硫化处理制备出Cu2ZnSnS4薄膜,分析第一步硫化(即预硫化)对Cu2ZnSnS4薄膜特性的影响。结果表明,预硫化处理可促进前驱体的硫化反应。经过预硫化处理的Cu2ZnSnS4薄膜的结晶度优于未进行预硫化处理的Cu2ZnSnS4薄膜。当预硫化温度为350℃时,增加预硫化时间有利于硫化反应的进行,并抑制Sn元素损失,但过长的预硫化时间导致Cu2ZnSnS4薄膜中易出现二次相,影响薄膜的特性。预硫化温度350℃、预硫化时间10 min的Cu2ZnSnS4薄膜结晶度最优,薄膜组分具有贫Cu、富Zn特性,且薄膜表面无孔隙。     

Selenization of electrodeposited copper–indium alloy thin films for solar cell applications

Copper–Indium (Cu–In) alloys with sulfur and selenium have technological importance in the development of thin film solar cell technology. We have used potentiostatic electrochemical technique with three-electrode geometry for the deposition of Cu–In alloy thin films in an aqueous electrolyte. Cathodic voltammetry (CV) was thoroughly studied to optimize the electrodeposition parameters. The deposition potential for Cu–In alloy was found to be in the range ?0.70 to ?0.85 V versus Ag/AgCl reference electrode. Polycrystalline Cu_xIn_y thin films were electrodeposited from aqueous bath at room temperature and 45 °C. Effect of concentration of citric acid was extensively studied by CV measurements. The as-deposited Cu–In films were characterized with a range of characterization techniques to study the structural, morphological, compositional and electrical properties. Thin layers of Cu–In were selenized in a homemade tubular furnace at 400 ^°C, which reveals the formation of polycrystalline CuInSe₂ (CISe) thin films with tetragonal structure. The band gap of CISe thin film was estimated ~1.05 eV by optical absorption spectroscopy. Nearly stoichiometric CISe thin film, Cu = 25.25 %, In = 26.48 % and Se = 48.27 % was obtained after selenization. The linear behavior of current density–voltage (J–V) was observed for Cu–In alloy thin films whereas, the selenized Cu–In alloy films (CISe) possess rectifying properties.     

Preparation of Cu3SnS4 film with single ceramic target magnetron sputtering for Pt-free counter electrode of dye-sensitized solar cell

Journal of Materials Science: Materials in Electronics - Cu3SnS4 (CTS) films were successfully prepared on FTO glass via DC magnetron sputtering by using a single ceramic target. The CTS/FTO glass...     

Diffusion and adhesion properties of Cu films on polyimide substrates

Copper thin films were prepared on polyimide (PI) substrates by physical vapor deposition (PVD) and chemical vapor deposition (CVD). Titanium nitride (TiN) diffusion barrier layers were deposited between the copper films and the PI substrates by PVD. Auger electron spectroscopy compositional depth profile showed that TiN barrier layer was very effective in preventing copper diffusion into PI substrate even after the Cu/TiN/PI samples were annealed at 300 °C for 5 h. For the as-deposited CVD-Cu/PI, CVD-Cu/TiN/PI, and as-deposited PVD-Cu/PI samples, the residual stress in Cu films was very small. Relatively larger residual stress existed in Cu films for PVD-Cu/TiN/PI samples. For PVD-Cu/TiN/PI samples, annealing can increase the peeling strength to the level observed without a diffusion barrier. The adhesion improvement of Cu films by annealing treatment can be attributed to lowering of the residual tensile stress in Cu films.     

N掺杂Cu2O薄膜的低温沉积及快速热退火研究

采用氧化亚铜(Cu_2O)陶瓷靶,利用射频磁控溅射沉积法在氮气和氩气的混合气氛下制备了N掺杂Cu_2O(Cu_2O∶N)薄膜,并在N_2气氛下对薄膜进行了快速热退火处理,研究了N_2流量和退火温度对Cu_2O∶N薄膜的生长行为、物相结构、表面形貌及光电性能的影响。结果显示,在衬底温度300℃、N_2流量12sccm条件下生长的薄膜为纯相Cu_2O薄膜;在N_2气氛下对预沉积薄膜进行快速热退火处理不影响薄膜的物相结构,薄膜的结晶质量随退火温度(450℃)的升高而显著改善;快速热退火处理能改善薄膜的结晶质量和缺陷,降低光生载流子的散射,增强载流子的传输,预沉积Cu_2O∶N薄膜经400℃退火处理后展示出较好的电性能,薄膜的霍尔迁移率(μ)为27.8cm~2·V~(-1)·s~(-1)、电阻率(ρ)为2.47×10~3Ω·cm。研究表明低温溅射沉积和快速热退火处理能有效改善Cu_2O∶N薄膜的光电性能。     

CuO/SiO2复合薄膜的微观结构和发光特性分析

采用射频磁控共溅射法在硅衬底上沉积Cu/SiO₂ 复合薄膜,然后在N₂保护下高温退火,再于空气中自然冷却氧化,制备出低维CuO纳米结构,并对其微观结构和光致发光进行研究. 退火温度为1100℃时样品中主晶相为立方晶系的CuO（200）晶面,薄膜样品表面出现纳米线状结构,表面组分主要包括Cu、O元素,冷却氧化形成CuO/SiO₂复合薄膜. 该温度下退火后,光致发光谱中出现紫外光和紫光,这是由于复合薄膜中CuO的导带底到Cu空穴缺陷能级的跃迁导致的.     

Strain-mediated photoresponse of Fe–ZnO/rGO heterojunction photodetector by magnetic-field-assisted interface engineering

Journal of Materials Science: Materials in Electronics - Magnetic field-modulated interface engineering has been attained in Fe doped zinc oxide/reduced graphene oxide (rGO) layered thin films,...     

Interface stress induced hardness enhancement and superelasticity in polytetrafluoroethylene/metal multilayer thin films

Polytetrafluoroethylene (PTFE)/Al, PTFE/Cu, and PTFE/Ti multilayer thin films have been deposited in order to investigate effects of interface energy on mechanical properties. PTFE, which has a low surface energy of 19.2 mJ/m², was used to introduce a large interface energy into multilayer thin films. PTFE thin film was deposited by rf magnetron sputtering using a PTFE sheet target. Al, Cu, and Ti were deposited by dc magnetron sputtering. The multilayer thin films were fabricated sequentially without breaking vacuum. Substrate used was aluminosilicate glass. The modulation period was changed from 6.7 to 200 nm. The total thickness was about 200 nm for all samples. The internal stress of metal layers changed from tensile to compressive and increased with decreasing modulation period for all of PTFE/Al, PTFE/Cu, and PTFE/Ti. Both hardness enhancement and superelasticity were observed in the results of nanoindentation measurements. The energy dissipated during nanoindentation process (one load and unload cycle) decreased with decreasing modulation period. The minimum value of the ratio of dissipated/loaded energy was < 40%, which is smaller than the values obtained for monolithic PTFE or metal films (about 73% for PTFE and 87% for Al, 72% for Cu, and 71% for Ti, respectively). This meant that the PTFE/metal nano-multilayer thin films became more elastic with decreasing modulation period. The tendency of change in the mechanical properties strongly correlated to internal stress. Mechanisms involved in anomalous behaviors in film hardness and elasticity were discussed based on the relationship to interface energy, interface stress, and internal stress, induced by multilayering of the films. It is concluded that a large compressive stress introduced in the thin films increased the energy needed to deform elastically or plastically the thin film during indentation, resulting in the increase in hardness and elasticity. The nanoindentation analysis of the multilayer thin films emphasized that in PTFE/metal multilayer thin films mechanical properties of the films depend on interface stress induced by the accumulated interface energy, being independent of bulk materials properties composing thin films, resulting in increase in hardness and elasticity.     

Cu/Sn比率对Cu2SnSe3薄膜若干物理性质的影响

利用射频(RF)磁控溅射在玻璃基片上共溅射沉积Cu-Sn预制膜。采用固态硒化法,制备Cu/Sn化学计量比在1.87～2.22之间的Cu2SnSe3薄膜。研究了Cu/Sn比率对Cu2SnSe3薄膜的晶体结构、微结构、光学性能以及电学性能的影响。X射线衍射(XRD)结果表明,所制备的Cu2SnSe3薄膜为立方晶体结构,具有(111)择优取向;贫铜的Cu2SnSe3薄膜光学带隙Eg随着Cu/Sn比率增大而增大;富铜的Cu2SnSe3薄膜光学带隙Eg随着Cu/Sn比率增大而不变。薄膜电阻率为1.67～4.62mΩ.cm。