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A series of Zn-Sb thin films were deposited by direct current (DC) magnetron co-sputtering through fixing the sputtering power of Zn target while varying the sputtering power of Sb target. The deposited thin films were annealed at 673 K under Ar atmosphere for 1 h. X-ray diffraction (XRD) results show that the prepared thin film gradually transforms from β phase Zn 4 Sb 3 to ZnSb phase with increasing Sb sputtering power. It is found that the thermoelectric properties of the prepared Zn-Sb thin films are related to the phase transformation. Firstly, the carrier concentration decreases while the Hall mobility increases with increasing Sb sputtering power until 20 W, and then with further increasing Sb sputtering power, the carrier concentration increases while Hall mobility decreases. The thin films prepared by the Sb sputtering power of 20 W shows a mixed phase of ZnSb and Zn 4 Sb 3 and its Seebeck coefficient has a higher value than the samples with single β-Zn 4 Sb 3 or ZnSb phase. Through optimizing the ratio of β-Zn 4 Sb 3 to ZnSb phase in the mixed Zn-Sb thin film, an enhanced power factor of 1.91 × 10 −3 W/m K 2 can be obtained with a high Seebeck coefficient of 360 μV K −1 and a low resistivity of 6.79 × 10 −5 Ω m at 573 K. X-ray photoelectron spectroscopy (XPS) was used to investigate the binding energy of Zn and Sb in the thin film with a power factor of 1.91 × 10 −3 W/m K 2 and it is suggested that the weak bonding of the thin film could be one of the reasons resulting in enhanced thermoelectric performance.

Al-doped ZnO (AZO) has practical applications in the industry for thermoelectric generation, owing to its nontoxicity, low-cost and stability at high temperatures. In this study, AZO thin films with high quality were deposited on BK7 glass substrates at room-temperature by direct current reactive magnetron sputtering using Zn–Al alloy target. The deposited thin films were annealed at various temperatures ranging from 623 K to 823 K with a space of 50 K. It is found that the absolute value of Seebeck coefficient of AZO thin film annealed at 723 K increases stably with increasing of measuring temperature and reaches a value of ∼60 μV/K at 575 K. After that, Al-doping content was varied to further optimize the thermoelectric properties of AZO thin films. The power factor of AZO thin films with Al content of 3 wt% increased with increase of measuring temperature and the maximum power factor of 1.54 × 10−4 W m−1K−2 was obtained at 550 K with the maximum absolute values of Seebeck coefficient of 99 μV/K, which is promising for high temperature thermoelectric application.

N-type bismuth telluride (Bi2Te3) thermoelectric thin films were deposited by co-sputtering simple substance Te and Bi targets. The deposited films were annealed under various temperatures. The composition ratio, micro-structure and thermoelectric properties of the prepared films were systematically investigated by energy dispersive spectrometer, X-ray diffraction, four-probe method and Seebeck coefficient measurement system. When the annealing temperature is 400 °C, the stoichiometric N-type Bi2Te3 film is achieved, which has a maximum thermoelectric power factor of 0.821 × 10−3 W m−1 K−2. Furthermore, the dependence of Seebeck coefficient, electrical conductivity and power factor of the stoichiometric N-type Bi2Te3 film annealed at film 400 °C on the applied temperature ranging from 25 °C to 315 °C was investigated. The results show that a highest power factor of 3.288 × 10−3 W m−1 K−2 is obtained at the applied temperature of 275 °C. The structural and thermoelectric properties of the deposited bismuth telluride thin films are greatly improved by annealing and the Seebeck coefficient, electrical conductivity and power factor increase with the applied temperature rising, which are helpful and could be guidance for preparing the high-performance thin film thermoelectric materials for thermoelectric application.

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 304 cm −1 and 606 cm −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 0.76 nm. Optical transmission and absorption spectroscopy measurement reveal high absorption and energy band gap is of about 2.32 eV. The CdS thin film is of n-type conductivity and the resistivity is found to be in the order of 10 4 Ω cm. The CdS films annealed at 100 °C were demonstrated to be improvement in structural, electrical and optical properties.

HfO2 is one of the most important high refractive index materials for depositing high power optical mirrors. In this research, HfO2 thin films were prepared by dual-ion beam reactive sputtering method, and the laser-induced damage thresholds (LIDT) of the sample were measured in 1-on-1 mode for laser with 1064 nm wavelength. The results indicate that the LIDT of the as-grown sample is only 3.96 J/cm(2), but it is increased to 8.98 J/cm(2) after annealing under temperature of 200 degrees C in atmosphere. By measuring the laser weak absorption and SIMS of the samples, we deduced that substoichiometer is the main reason for the low LIDT of the as-grown sample, and the experiment results were well explained with the theory of electronic-avalanche ionization. (C) 2008 Elsevier B.V. All rights reserved.