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1.
CdS nanocrystals were synthesized by hot injection method using EG as solvent, polyvinylpyrrolidone as dispersant, triethanolamine as stabilizing agent, Cd(NO3)2·4H2O and H2NCSNH2 as cadmium and sulfur sources respectively. The synthesized nanocrystals were washed and ultrasonically dispersed with absolute ethanol to prepare nanocrystal ink. CdS thin films were deposited by dip-coating glass substrates with the nanocrystal ink and annealed at 450 °C in Ar atmosphere. Crystalline phase, morphology and element stoichiometry of the CdS nanocrystals derived from different synthesis temperatures were investigated by XRD, TEM and EDS. Surface morphology, crystalline phase and optical absorption spectrum of the CdS films were characterized by SEM, XRD and UV-Vis. 相似文献
2.
Thin films of CuInSe2 have been evaporated onto glass substrates by flash evaporation. The as-deposited films are amorphous and annealing in selenium
atmosphere produces polycrystalline films. The films were characterized bytem and x-ray diffraction techniques. The optical absorption of the films shows three energy gaps of 1·03, 1·07 and 1·22 eV.
The crystal field and spin-orbit splitting are thus found to be 0·04 eV and 0·16 eV respectively. The percentaged-character of the valence band states is ∼35%. The Arrhenius plot of electrical conductivity of films showed impurity ionization
ofE
A
= 75 meV. 相似文献
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4.
Tadataka Edamura Jun'ichiro Muto 《Journal of Materials Science: Materials in Electronics》1994,5(5):275-279
CuInSe2 thin films were electrodeposited on an indium-tin-oxide glass substrate by a pulse-plating technique from an aqueous electrolyte solution, containing CuSO4, InCl3 and SeO2 with the pH adjusted to 1.5 at room temperature. The deposited and heat-treated films were characterized structurally using X-ray diffraction (XRD), scanning electron microscopy (SEM) and auger electron spectroscopy (AES) analysis. The optical and the electrical properties of the films were also examined. When the film was submitted to heat-treatment above 300 C in air for 1 h, the sample showed a chalcopyrite structure and n-type conductivity with a carrier concentration of ~ 1017 cm–3 and a band-gap (direct allowed transition) energy of 0.99 eV. 相似文献
5.
Indium tin oxide (ITO) thin films were prepared on quartz glass substrates by a dip-coating process. The starting solution was prepared by mixing indium chloride dissolved in acetylacetone and tin chloride dissolved in ethanol. The ITO thin films containing 0 20 mol% SnO2 were successfully prepared by heat-treatment at above 400 °C. Chemical stability of sol were investigated by using a FTIR spectrometer. The electrical resistivity of the thin films decreased with increasing heat-treatment temperature, that is carrier concentration increased, and mobility decreased with increasing SnO2 content. The ITO thin films containing 12 mol% SnO2 showed the minimum resistivity of =1.2 × 10–3 ( cm). It also showed high carrier concentration of N=1.2 × 1020(cm–3) and mobility H=7.0(cm2 V–1 s–1). 相似文献
6.
Hai-Bing Xie Wei-Feng Liu Xin-Yi Li Fei Yan Guo-Shun Jiang Chang-Fei Zhu 《Journal of Materials Science: Materials in Electronics》2013,24(2):475-482
CuInSe2 thin films have been synthesized by selenization of co-sputtered Cu-In precursors using rapid thermal processing (RTP). Heat treatments from 400 to 450 °C for periods between 1 min and 10 min were carried out on (Cu-In)/Se precursors. Phase evolution as function of reaction temperature and holding time was analyzed according to XRD and SEM results. Severe Se loss during RTP was proved in our experiments and has been reported by many other researchers. To solve the problem, a new effective way of reducing Se loss was presented, which is based on low temperature heat treatment at 250 °C before high temperature annealing. Nearly single-phase CuInSe2 thin films have been achieved by annealing precursors at 250 °C for 5 min then 450 °C for 1 min. Se loss can be significantly reduced via low temperature heat treatment by the fact that under 250 °C, Se is evaporated mildly and largely consumed as Cu-Se and In-Se binary selenides. 相似文献
7.
Flash-evaporated technique has been developed for deposition of CuInSe2 thin films. A control over the stoichiometry and chemical composition of the films has been obtained by varying the deposition
parameters. Single phase chalcopyrite structure films with optical gap ∼ 1·15 eV have been obtained. The electronic properties
of the films have been tailored for solar cell applications. 相似文献
8.
《Materials Letters》1988,7(4):131-133
Knowledge of impurities in thin films is important for fabrication and characterization of photovoltaic devices. The lightimpurity distribution in electrodeposited CuInSe2 thin films has been investigated by an elastic recoil detection method using a 30 MeV 35Cl beam and identifying the recoil masses using a time-of-flight technique. It was found that both oxygen and hydrogen were present and distributed uniformly throughout the thickness studied. Upper limits for carbon and nitrogen were also established. The energy spectra for oxygen and hydrogen were deconvolved to obtain the relative concentrations as a function of depth. Using the same technique, the compositional uniformity of Cu, In and Se was also determined, yielding results qualitatively consistent with that obtained by secondary ion mass spectroscopy. 相似文献
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A. Kumar A. L. Dawar P. K. Shishodia G. Chauhan P. C. Mathur 《Journal of Materials Science》1993,28(1):35-39
Films of CulnSe2 have been grown using a technique similar to close-spaced vapour transport. The effect of substrate temperature and the distance of the substrate from the source have been optimised to grow well-oriented chalcopyrite phase of CuInSe2. D.c. conductivity and Hall coefficient studies have been made in the temperature range 77–300 K. The films grown at a substrate temperature of 350 °C have an electron mobility of 3.4×103 cm2V–1 s–1 at 77 K. 相似文献
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Indium tin oxide (ITO) thin films with well-controlled layer thickness were produced by dip-coating method. The ITO was synthesized by a sol-gel technique involving the use of aqueous InCl3, SnCl4 and NH3 solutions. To obtain stable sols for thin film preparation, as-prepared Sn-doped indium hydroxide was dialyzed, aged, and dispersed in ethanol. Polyvinylpyrrolidone (PVP) was applied to enhance the stability of the resulting ethanolic sols. The transparent, conductive ITO films on glass substrates were characterized by X-ray diffraction, scanning electron microscopy and UV-Vis spectroscopy. The ITO layer thickness increased linearly during the dipping cycles, which permits excellent controllability of the film thickness in the range ~ 40-1160 nm. After calcination at 550 °C, the initial indium tin hydroxide films were transformed completely to nanocrystalline ITO with cubic and rhombohedral structure. The effects of PVP on the optical, morphological and electrical properties of ITO are discussed. 相似文献
13.
Films of spinel-type ferrite, MFe2O4 (M=Ni, Co, Mg, Li0.5Fe0.5) have been prepared by a dip-coating method from the sol-gel process. Ferric nitrate, nickel nitrate, cobalt nitrate and lithium nitrate were used as raw materials, and glycerol and formamide were used as solvents. A film was prepared by dipping a silica glass plate. The spinel-type ferrite was obtained by heat-treatment at 700–900°C for 2 h in air. The film thickness was about 0.8 m. The saturation magnetization, r, of the film and powder with composition 50NiO·50Fe2O3 was 196 emu cm–3 and 29.1 emu g–1, respectively, and the coercive force,H
c, was 140 and 95 Oe, respectively, after heat-treatment at 800°C for 2 h. In particular, the films were shown to have a much largerH
c than the powder. The grain growth of spinel ferrite may be subject to restriction because it is in progress above an amorphous base-plate. The crystals are therefore aligned with the base-plate and have uniaxial anisotropy. 相似文献
14.
A. Ashour 《Journal of Materials Science: Materials in Electronics》2006,17(8):625-629
Semiconducting thin films of CuInSe2 have been grown by thermal annealing in air of evaporated layers of Cu, In and Se on glass substrates. The structure of the
films has been studied using the X-ray diffraction (XRD). The films were polycrystalline and showed mixture phases (binary
and ternary) depending on the annealing temperature. The electrical properties revealed resistivity range of 101–104Ωcm, respectively. The resistivity influenced with the annealing temperature and decreased with increasing temperature. The
films have been analyzed for optical band gap. 相似文献
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16.
This study involves the characterization of thin films of copper indium diselenide (CuInSe2) deposited on soda-lime glass substrates using a two-step process. In this technique electron-beam-evaporated Cu-In precursor layers were reacted with an atmosphere containing H2Se gas. The morphological and structural aspects of the CuInSe2 layers were studied (by scanning electron microscopy and X-ray diffraction) as a function of the Cu-In film morphology and the selenization temperature profile and exposure time. It was found that the Cu-In precursor morphology has a significant influence on the structural properties of the final CuInSe2 film. Selenization of the Cu-In alloys (irrespective of the structure considered) directly at high temperature resulted in films with poor structural properties. However, a vast improvement in the adhesion properties and morphology of the CuInSe2 films were observed when the Cu-In films were exposed to a reactive selenium atmosphere while ramping the temperature between 150 C and 400 C. Selenization of triple-layer structures (Cu/In/Cu and In/Cu/In) resulted in films with good structural properties and excellent compositional uniformity. 相似文献
17.
Davoud Dastan Seyedeh Leila Panahi Nandu B. Chaure 《Journal of Materials Science: Materials in Electronics》2016,27(12):12291-12296
A dip-coating technique was employed to prepare anatase phase of titania thin films. Fluorine doped tin oxide substrates were used to prepare titania thin films. The samples were annealed at 550 °C for 18 h. X-ray diffraction results revealed the amorphous and anatase phases of TiO2 for as-synthesized and annealed samples, respectively. The crystallite size of anatase TiO2 thin films was almost 25 nm for annealed samples. UV–visible confirmed the energy band gap 3.86 and 3.64 eV for as-prepared and calcinated titania thin films. The reduction in the energy band gap could be due to the change in crystallization and agglomeration of small grains after calcination. The morphology of the prepared films was investigated by field emission scanning electron microscopy which demonstrated the agglomeration of spherical particles of TiO2 with average particle size of about 30 nm. The molecular properties (chemical bonding) of the samples were investigated by means of Fourier Transform Infrared (FTIR) spectroscopy. FTIR analysis exhibited the formation of titania, functional group OH, hydroxyl stretching vibrations of the C–OH groups, bending vibration mode of H–O–H, alkyl C–H stretch, stretching band of Ti–OH, CN asymmetric band stretching, and C=O saturated aldehyde. 相似文献
18.
Yasutaka Takahashi Masaaki Kanamori Hiroyuki Hashimoto Yoshimitsu Moritani Yoshihiro Masuda 《Journal of Materials Science》1989,24(1):192-198
Low-pressure organometallic chemical vapour deposition (OMCVD) and dip-coating of VO2 films using vanadyl tri(isobutoxide) as the starting material were investigated. In OMCVD, discontinuous VO2 films, which were composed of fine needle crystals, formed under very limited conditions, around 600° C with a flow rate of oxygen gas of 0.2 to 0.5 cm3 sec–1. However, very uniform and tightly packed VO2 films were grown by deposition at 300 to 700° C in the absence of oxygen gas and subsequent annealing in nitrogen at 500° C for 2 h. The films exhibited a sharp semiconductor to metal transition at 60 to 70° C, accompanied by a change in the resistivity by four to five orders of magnitude. In dip-coating with two-step heat-treatments (300° C for 1 h in nitrogen and subsequently 500° C for 2 h in nitrogen), of the gel films formed from VO(O-i-Bu)3-H2O-i-PrOH system, uniform (0 1 1) oriented VO2 films were formed. A transition in the electrical conductivity by two to two and a half orders of the magnitude was found to occur around 60° C. Before and after the transition, no distinct variation in the XRD pattern was observed. 相似文献
19.
CuInSe2 thin films were prepared by electrodeposition from aqueous solution, containing CuSO4, InCl3 and SeO2 under d.c. step pulse-voltage on d.c., and pulse-plating conditions. The films were characterized by scanning electron microscopy, energy dispersive spectrometry and X-ray diffraction. The influence of deposition technique on film composition, morphology and structure were studied. Heat treatment of pulse-plated films under vacuum resulted in the formation of CuInSe2 with single-phase chalcopyrite structure. 相似文献