Deposition of CuInS2 thin films using copper- and indium/sulfide-containing precursors through a two-stage MOCVD method

Copper indium disulfide (CuInS2; CIS) films were deposited on various substrates by two-stage metal-organic chemical vapor deposition (MOCVD) at relatively mild conditions, using Cu- and In/S-containing precursors without toxic H2S gas: first, a pure Cu thin film was prepared on glass or indium/tin oxide glass substrates by using a single-source precursor, bis(ethylbutyrylacetato)copper(II) or bis(ethylisobutyrylacetato)copper(II); second, on the resulting Cu film, tris(N,N-ethylbutyldithiocarbamato)indium(III) was treated to produce CIS films by a MOCVD method at 430 degrees C. In this process, their thicknesses and stoichiometries were found to be elaborately controlled on demand by adjusting the process conditions. The optical band gap of the stoichiometric CIS film was about 1.41 eV, which is in the near-optimal range for harvesting solar radiation energy.     

Single source molecular precursor routes to lead chalcogenides

The use of single-source molecular precursors for lead chalcogenide thin films by CVD or as nanoparticles by solution methods is reviewed. The potential applications of these materials in solar energy are discussed along with the relative advantages of the various methods.     

Single-Source III/V Precursors: A New Approach to Gallium Arsenide and Related Semiconductors

Until recently, the production of gallium arsenide, indium phosphide, and related compound semiconductors has fallen in the domain of the materials scientist and the electrical engineer. By clever use of classical chemistry, exemplified by the thermal reaction of Me₃Ga and AsH₃, it is possible to make semiconductors on a commercial scale. However, there are some drawbacks associated with the existing methodology, including the environmental and health hazards of handling pyrophoric and toxic starting materials as well as stoichiometry control problems and undesirable side reactions. Can the synthetic inorganic and organometallic chemist play a useful role in this important area by designing and developing new reagents for the production of semiconductor materials? We believe the answer is yes, and in this article we discuss a new approach to the preparation of GaAs and InP thin films based on single-source precursors. These compounds feature strong σ-bonding between the group III and V elements, together with substituents that are capable of facile thermal elimination. The III/V precursors are more stable toward air and moisture and considerably less toxic than either adducts or mixtures of group III and V compounds.     

The single molecular precursor approach to metal telluride thin films: imino-bis(diisopropylphosphine tellurides) as examples

Interest in metal telluride thin films as components in electronic devices has grown recently. This tutorial review describes the use of single-source precursors for the preparation of metal telluride materials by aerosol-assisted chemical vapour deposition (AACVD) and acquaints the reader with the basic techniques of materials characterization. The challenges in the design and synthesis of suitable precursors are discussed, focusing on metal complexes of the recently-developed imino-bis(diisopropylphosphine telluride) ligand. The generation of thin films and nanoplates of CdTe, Sb(2)Te(3) and In(2)Te(3) from these precursors are used as illustrative examples.     

Sol–gel processed indium zinc oxide thin film and transparent thin-film transistors

Indium–zinc oxide (IZO) thin films were fabricated by spin coating using acetate- and nitrate-based precursors, and thin film transistors (TFTs) were further fabricated employing the IZO films as the active channel layer. The impact of the indium concentration on the properties of the solutions, the structure and optical transmittance properties of the IZO films and the IZO TFTs device properties were researched in this article. The IZO films with amorphous structure were obtained when the annealing temperature is 500 °C. The transmittance could reach ~90 % (including glass substrate) during the visible region of 400–760 nm. Higher indium concentration can improve the IZO TFTs’ filed effect mobility. A I_on–I_off of 6.0 × 10⁶ and a mobility of 0.13 cm²/Vs were obtained when the indium concentration is 60 %. IZO TFTs’ performance could deteriorate when the indium concentration more than 60 %.     

Microstructural and optical characterizations of sol–gel based antimony doped indium oxide coatings on glass

Thin films of antimony doped indium oxide on glass has been developed by sol–gel dipping process. Four different Sb: In atomic ratios, 1:99, 4:96, 7:93, 10:90 were selected for the precursors. Pressure flow curve of the precursors were Newtonian which apparently developed homogeneous films baking at 500 °C in air. The EDS study restricted to the study of the films of only two Sb: In atomic ratios, namely 7:93, 10:90 as antimony sublimes during baking. Polycrystalline nature of the nanostructured films were revealed by X-ray diffractogram and SAED analysis. Transmission electron microscopy study shows the presence of nanoclusters of maximum average size, ~11 nm. The band gap evaluation from the absorption spectra suggested the presence of bulk indium oxide, nanoclustered indium oxide and antimony doped indium oxide. Presence of Sb(V) in the system was evidenced from the characteristic absorption spectra in the UV region. Visible transmissivity and electrical resistivity suggested the films to be prospective transparent conducting oxide material. The photoluminescence study exhibited the characteristic emissions for defect centres.     

石墨烯透明导电薄膜

石墨烯是一种新型二维晶体材料,它独特的单原子层结构显示出许多优异的物理化学性质。以石墨烯为原料制备的透明导电薄膜继承了石墨烯的优点,与氧化铟锡(ITO)薄膜相比,具有更好的力学强度、透光性以及化学稳定性,已逐渐成为全世界范围内的研究热点。本文首先介绍了石墨烯的光电性能,然后分别从石墨烯透明导电薄膜的前驱体和制备方法两个不同的角度,归纳总结了最近几年石墨烯透明导电薄膜的研究进展,就目前所面临的问题进行了讨论,并展望了石墨烯透明导电薄膜的未来发展。     

Electrodeposition and characterization of PbSe films on indium tin oxide glass substrates

Electrodeposition of lead selenide (PbSe) thin films on indium tin oxide (ITO) covered glass is described. While disodium salt of ethylenediaminetetraaceticacid was used to complex the lead ions, well crystallized, nearly stoichiometric and mirror-like PbSe films were deposited on ITO glass in potentiostatic mode using aqueous acidic electrolyte containing Pb and Se precursors at different bath temperature. The improvement of crystallinity of the PbSe films deposited at different temperature was studied using X-ray diffraction and Raman scattering. The morphology and composition of the films were characterized by scanning electron microscopy and energy disperse analysis by X-ray, respectively. The optical property of the film was studied by optical measurement techniques.     

MOCVD-derived highly transparent, conductive zinc- and tin-doped indium oxide thin films: precursor synthesis, metastable phase film growth and characterization, and application as anodes in polymer light-emitting diodes

Four diamine adducts of bis(hexafluoroacetylacetonato)zinc [Zn(hfa)(2).(diamine)] can be synthesized in a single-step reaction. Single crystal X-ray diffraction studies reveal monomeric, six-coordinate structures. The thermal stabilities and vapor phase transport properties of these new complexes are considerably greater than those of conventional solid zinc metal-organic chemical vapor deposition (MOCVD) precursors. One of the complexes in the series, bis(1,1,1,5,5,5-hexafluoro-2,4-pentadionato)(N,N'-diethylethylenediamine)zinc, is particularly effective in the growth of thin films of the transparent conducting oxide Zn-In-Sn-O (ZITO) because of its superior volatility and low melting point of 64 degrees C. ZITO thin films with In contents ranging from 40 to 70 cation % (a metastable phase) were grown by low-pressure MOCVD. These films exhibit conductivity as high as 2900 S/cm and optical transparency comparable to or greater than that of commercial Sn-doped indium oxide (ITO) films. ZITO films with the nominal composition of ZnIn(2.0)Sn(1.5)O(z)() were used in fabrication of polymer light-emitting diodes. These devices exhibit light outputs and current efficiencies almost 70% greater than those of ITO-based control devices.     

Polymer-assisted preparation of nanoscale films of thermoelectric PbSe and PbTe and of lead chalcogenide-polymer composite films

Polymer films of polyethyleneoxide (PEO) or poly(L-lactide) (PLLA) containing a single-source precursor for either PbSe or PbTe were used to produce films of nanoparticles of these thermoelectric materials. The monomeric homoleptic chalcogenolates lead(II) bis-(2,4,6-trifluoromethylphenylselenolate) Pb[SeC(6)H(2)(CF(3))(3)](2) and lead(II) bis-[tris(trimethylsilyl)silyl-tellurolate] Pb[TeSi(SiMe(3))(3)](2) were used as single-source precursors for the thermolytic formation of the lead chalcogenides. The thickness and the quality of as-obtained thin films depended decisively on the spin-coating conditions, on the polymer, on the precursor concentration in the composite film before thermolysis and on the annealing time. Thin layers of particles of 30-50 nm size and high crystallinity were obtained. They were characterized by X-ray diffraction, thermal analysis and electron microscopy.     

MOCVD生长铁电氧化物薄膜MO源研究进展

高性能铁电氧化物薄膜是当今功能材料的研究热点之一.随着新型MO源的不断研究与开发,利用MOCVD技术制备高质量铁电薄膜材料得到了快速的发展.本文在分析金属醇盐和金属β-二酮化合物等MO源的结构与其物性依赖关系基础上,分类综述了近年来在用于MOCVD方法生长铁电氧化物薄膜的新型MO源研究和开发方面的发展动态与趋势,为MOCVD方法制备铁电薄膜材料MO源的选择提供有用的参考与借鉴.     

Ultraviolet-Laser-Induced Crystallization of Sol-Gel Derived Indium Oxide Films

Modification of sol-gel derived indium oxide thin films using ultraviolet lasers was investigated. Irradiation by an ArF excimer (6.4 eV) and the fourth harmonic generation of a Nd : YAG laser (4.7 eV) was found to be effective in crystallization with a loss of hydroxyl groups and a decrease in the sheet resistance of the sol-gel films. Transparent crystalline indium oxide films were successfully obtained by 6.4 eV laser irradiation at fluences below 20 mJ/(cm2·shot), whereas degradation of the films was induced by a relatively high-fluence beam.     

Microstructure analysis of sol‐gel‐derived nanocrystalline ITO thin films

The technique for ITO (Tin‐doped indium oxide) thin films by sol‐gel process is presented in this paper. After annealing at 500° for 15 min, ITO gel films get transformed into nanocrystallined indium tin oxide films. We studied the microstructure of ITO thin film which is closely related to optical and electrical properties. The microstructure of ITO thin film can be observed through high‐resolution transmission electronic spectroscopy (HRTEM) and the Fast Fourier Transform (FFT) technique. The film is nanocrystallite with grain sizes about 20 nm. Also, the surface chemical components were studied by XPS spectra. The transmission and the resistivity of ITO films is 97.0% and 3.5 × 10^?3 Ω?cm, respectively. Copyright © 2010 John Wiley & Sons, Ltd.     

水溶液法制备图案化TiO2薄膜

从硫酸钛Ti(SO4)2的水溶液出发, 采用化学浴沉积和电沉积法来制备图案化TiO2薄膜. 通过硫酸和双氧水来稳定Ti4+, 配制了pH=1.0的硫酸钛溶液和pH=1.6的过氧硫酸钛溶液. 结合微接触印刷术在硅基底上制得自组装膜预图案, 再化学浴沉积TiO2即可得规则图纹. 无机配体对钛溶液的稳定性和TiO2的晶型均有影响, 溶液的酸度关系到所得图案的质量. 过氧硫酸钛溶液同样适用于电沉积, 在导电玻璃基底上旋涂光刻胶后选择性曝光、显影, 通过控制阴极电位可获得高差达200 nm的清晰图案.     

CO-sensing properties of undoped and doped tin oxide thin films prepared by electron beam evaporation

Undoped thin films of tin oxide and those doped with indium oxide and nickel oxides were deposited by electron beam evaporation. The effects of the film thickness and preparation conditions (films prepared with or without the presence of oxygen environment during deposition) on the optical and carbon monoxide sensing properties of the films were studied. The films were characterized using X-ray diffraction and X-ray photoelectron spectroscopy and optical spectroscopy techniques. All the films were found to be amorphous. It was found that the sensitivity of the films to CO increased with the thickness and the porosity of the films. It was found that their selectivity to CO gas relative to CO₂ and SO₂ gases could be improved upon doping the films with indium (or nickel) oxide.     

Synthesis and thermodynamic characteristics of aluminum, gallium, and indium pivalates

Aluminum, gallium and indium pivalates, which are the most promising precursors for fabrication of oxide films in chemical vapor deposition, were synthesized. Their main thermodynamic characteristics were determined and discussed.     

Coordination Chemistry of Aluminum,Gallium, and Indium at Transition Metals

The current upswing in the interest in organoelement chemistry of Group 13 metals is attributed not least to the establishment of the coordination chemistry of R_aE fragments (E=Al, Ga, In; a=1, 2) at d-block metals (M). Recently the availability of low-valent organoelement compounds as building blocks for synthesis has substantially enriched the structure chemistry of this class of compounds. The M–E bonding conditions and the question of the significance of M(d_π)-E(p_π) backbonding as well as potential applications in materials science, for example, as single-source precursors for the deposition of thin intermetallic films by chemical vapor deposition, are discussed.     

DSC of as-deposited thin films dip-coated on the substrate

The formation process of a ceramic (indium oxide) thin film (thickness: approximately 20 nm to several microns) was investigated by thermal analyses. Thermal changes of an organic precursor, indium(III) 2-ethylhexanoate, dip-coated on a glass substrate was successfully detected by DSC in air. Exothermic phenomena were observed at marked lower temperatures for the thin films than for the bulk material; thinner films had slightly lower peak temperatures. The reaction mechanism is discussed with reference to mass spectra of the evolved gases.     

Charge transport and optical properties of MOCVD-derived highly transparent and conductive Mg- and Sn-doped In2O3 thin films

Mg- and Sn-doped In2O3 (MgIn(x)Sn(y)O(z), 6.0 < x < 16.0; 3.0 < y < 8.0) thin films were grown by low-pressure metal-organic chemical vapor deposition using the volatile metal-organic precursors tris(2,2,6,6-tetramethyl-3,5-heptanedionato)indium(III) [In(dpm)3], bis(2,4-pentanedionato)tin(II) [Sn(acac)2], and bis(2,2,6,6-tetramethyl-3,5-heptanedionato)(N,N,N',N'-tetramethylethylenediamine)magnesium(II) [Mg(dpm)2(TMEDA)]. Films in this compositional range retain the cubic In2O3 bixbyite crystal structure. The highest conductivity is found to be approximately 1000 S/cm for an as-grown film with a nominal composition MgIn14.3Sn6.93O(z). Annealing of such films in a vacuum raises the conductivity to approximately 2000 S/cm. The optical transmission window of the present films is significantly wider than that of typical indium tin oxide (ITO) films from 300 to 3300 nm, and the transmittance is also greater than or comparable to that of commercial ITO films.     

An investigation of the microstructure,optical and electrical properties of ZITO thin film using the sol–gel method

The multi-compound ZITO transparent conductive oxide (TCO) thin films were synthesized using the sol–gel method. The ZITO thin films with various volume ratios of ZnO to ITO (1:1, 2:1 and 9:1) were crystallized at different temperatures (600–700 °C). The results showed that the crystalline characteristics and optical transmittance were mainly dependent on ITO content and crystallization. Notably, the 650 °C Z₉ITO film not only had better conductivity but also possessed excellent optical transmittance. In addition, the surface roughness of the ZITO films and optoelectric properties of IZO (indium doped ZnO) films were analyzed to confirm the contribution of indium dopants on the optical transmittance. Also, the ZITO films were subjected to the effects of indium and tin dopants and this improved the related characteristics of ZnO films.