Search

p-Type antimony telluride (Sb 2Te 3) thermoelectric thin films were deposited on BK7 glass substrates by ion beam sputter deposition using a fan-shaped binary composite target. The deposition temperature was varied from 100°C to 300°C in increments of 50°C. The influence of the deposition temperature on the microstructure, surface morphology, and thermoelectric properties of the thin films was systematically investigated. x-Ray diffraction results show that various alloy composition phases of the Sb 2Te 3 materials are grown when the deposition temperature is lower than 200°C. Preferred c-axis orientation of the Sb 2Te 3 thin film became obvious when the deposition temperature was above 200°C, and thin film with single-phase Sb 2Te 3 was obtained when the deposition temperature was 250°C. Scanning electron microscopy reveals that the average grain size of the films increases with increasing deposition temperature and that the thin film deposited at 250°C shows rhombohedral shape corresponding to the original Sb 2Te 3 structure. The room-temperature Seebeck coefficient and electrical conductivity range from 101  μV K −1 to 161  μV K −1 and 0.81 × 10 3 S cm −1 to 3.91 × 10 3 S cm −1, respectively, as the deposition temperature is increased from 100°C to 300°C. An optimal power factor of 6.12 × 10 −3 W m −1 K −2 is obtained for deposition temperature of 250°C. The thermoelectric properties of Sb 2Te 3 thin films have been found to be strongly enhanced when prepared using the fan-shaped binary composite target method with an appropriate substrate temperature. [ABSTRACT FROM AUTHOR]

In this work, a simple method for fabricating Cu 2 ZnSnSe 4 (CZTSe) thin film by ion-beam sputtering without post-selenization is proposed. The influence of annealing temperature on the composition, the micro-structure, the morphology, the electrical and optical properties of CZTSe thin films has been established. The relatively low annealing temperature of 400 °C is considered as very positive for obtaining the optimized Cu-poor and Zn-rich CZTSe films with pure CZTSe phase, high crystallinity, P-type conduction and ideal optical band-gap. These interesting features have been used in the prototype photovoltaic devices with a conversion efficiency of 4.67%. These are the first results concerning the use of ion-beam sputtering CZTSe films for photovoltaic application and further improvement of device performance is expected. [ABSTRACT FROM AUTHOR]

Measurements of electronic structure, microstructure and thermoelectric properties of zinc antimonide thin films prepared by direct current magnetron co-sputtering were carried out. The as-deposited zinc antimonide thin film had a very high resistivity similar to insulating ceramics, which was due to a low binding energy of both zinc and antimony, with the electron scattering increases and impedes the current transport. With the increase in annealing temperature, the films became more crystalline and the thermoelectric properties were also improved. The resistivity of the film decreased rapidly with its crystallinity when the annealing temperature was above 350 °C. The Seebeck coefficients of the thin films were positive, indicating that the films were P-type. The Seebeck coefficient of those samples increased with increasing annealing temperature. The thin film annealed at 400 °C has an optimal power factor of 1.87 × 10 −3 Wm −1 K −2 with a Seebeck coefficient of 300 μVK −1 and a resistivity of 4.82 × 10 −5 Ωm at 573 K. [ABSTRACT FROM AUTHOR]

Antimonide cobalt thin films were deposited on BK7 glass substrates at various substrate temperatures by ion beam sputtering deposition with a fan-shape target. The influence of deposition temperature on the microstructure and thermoelectric properties of antimonide cobalt thin films were systematically investigated. It is found that the Seebeck coefficient of the thin film increases at first and then decreases with the increasing deposition temperature. The Seebeck coefficient of the sample deposited at 250 °C has maximum value and increases stably when the measuring temperature increased from room-temperature to 600 K. The electrical conductivity of the thin film increases significantly to 5.6 × 10 4 S cm −1 when the deposition temperature was 450 °C and then decreases greatly when the temperature increased to 500 °C and 550 °C. The behavior of electrical conductivity of the sample deposited at 250 °C changes from metallic to semiconducting after the measuring temperature exceeded 540 K. The power factor of antimonide cobalt thin film deposited at 250 °C has a maximum value of 0.93 × 10 −4 W m −1 K −2 at room-temperature and then increases to 3.5 × 10 −4 W m −1 K −2 when the measuring temperature was 540 K. [ABSTRACT FROM AUTHOR]

Highlights: [•] Using DC and RF co-sputtering to deposit bismuth telluride thin films. [•] Sputtering Bi and Te target respectively instead of the traditional Bi2Te3 target. [•] Influences of annealing temperatures on thermoelectric properties and micro-structure. [•] Dependence of thermoelectric properties on the applied temperature. [ABSTRACT FROM AUTHOR]

Abstract: Deposition of cadmium sulfide (CdS) thin film on BK7 glass substrates has been prepared by a dry and in situ fabrication process with ion-beam sputtering deposition at room temperature. The structural, optical and electrical properties of CdS thin film were investigated. X-ray diffraction (XRD) analysis indicates the formation of polycrystalline CdS film with the mixed structure of cubic and hexagonal wurtzite phase. The Raman peaks are observed at 304cm−1 and 606cm−1, and these peaks are identified as the first and second order LO optical phonons form of the CdS film. Energy dispersive X-ray Spectrometer (EDS) shows no other impurity elements, except Cd and S. The as-deposited film exhibits good transfer of the sintered target material with almost the same Cd/S ratio. Scan electron microscopy (SEM) and atomic force microscopy (AFM) reveal that the CdS thin film has a smooth surface and exhibited an obvious columnar growth indicating the c-axis preferred orientation. The detected room-mean-square (RMS) roughness by AFM is 0.76nm. Optical transmission and absorption spectroscopy measurement reveal high absorption and energy band gap is of about 2.32eV. The CdS thin film is of n-type conductivity and the resistivity is found to be in the order of 104 Ωcm. The CdS films annealed at 100°C were demonstrated to be improvement in structural, electrical and optical properties. [Copyright &y& Elsevier]

Abstract: CuInSe2 (CIS) thin films were prepared by ion beam sputtering deposition of copper layer, indium layer and selenium layer on BK7 glass substrates followed by annealing at different temperatures for 1h in the same vacuum chamber. The influence of annealing temperature (100–400°C) on the structural, optical and electrical properties of CIS thin films was investigated. X-ray diffraction (XRD) analysis revealed that CIS thin films exhibit chalcopyrite phase and preferential (112) orientation when the annealing temperature is over 300°C. Both XRD and Raman show that the crystalline quality of CIS thin film and the grain size increase with increasing annealing temperature. The reduction of the stoichiometry deviation during the deposition of CIS thin films is achieved and the elemental composition of Cu, In and Se in the sample annealed at 400°C is very near to the stoichiometric ratio of 1:1:2. This sample also has an optical energy band gap of about 1.05eV, a high absorption coefficient of 105 cm−1 and a resistivity of about 0.01Ωcm. [Copyright &y& Elsevier]