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In conventional thin film thermoelectric generators, heat flow running vertical to film surface is used. The hot side and the cold side are just separated by the thickness of the films and to maintain the temperature difference between both sides remains a key challenge. Here, we demonstrate the properties of our designed thin film thermoelectric generators with heat flow running parallel to film surface, where a larger temperature difference between both sides is maintained. The maximum output power of our generator can reach 19.13 μW at the temperature difference of 85 K.

ZnO:Fe films with various piezoelectric coefficient d33 were employed to fabricate high frequency surface acoustic wave (SAW) filters on Si by conventional photolithography technology. Comparing with the SAW filters on undoped ZnO films, the electromechanical coupling factor and bandwidth, respectively, increases 75.7% and 14.8%, while the insertion loss decreases 20.3% when using Zn0.988Fe0.012O films with a d33 of ∼127 pC/N. Through annealing demonstration, d33 is considered as the intrinsic factor determining the SAW properties of filters, and the properties are improved by O2 annealing. ZnO:Fe films with enhanced d33 is promising for high frequency, low-loss, and wideband SAW applications.

A multi-channel readout ASIC for pixelated CZT detectors has been developed for gamma-ray spectroscopy applications. Each channel consists of a low noise dual-stage charge sensitive amplifier (CSA), a CR-(RC)4 semi-Gaussian shaper and a class-AB output buffer. The equivalent noise charge (ENC) of input PMOS transistor is optimized for 5 pF input capacitance and 1 μs peaking time using gm/ID design methodology. The gain can be adjusted from 100 mV/fC to 400 mV/fC and the peaking time can be adjusted from 1 μs to 4 μs. A 16-channel chip has been designed and fabricated in 0.35 μm 2P4M CMOS technology. The test results show that the chip works well and fully satisfies the design specifications. The ENC was measured to be 72 e + 26 e/pF at 1 μs peaking time and 86 e + 20 e/pF at 4 μs peaking time. The non-uniformity of the channel gain and ENC was less than ±12% and ±11% respectively for 16 channels in one chip. The chip was also tested with a pixelated CZT detector at room temperature. The measured energy resolution at 59.5 keV photopeak of 241Am and 122 keV photopeak of 57Co were 4.5% FWHM and 2.8% FWHM for the central area pixels, respectively.

Single-phase Bi5Ti3FeO15 and Bi6Ti3Fe2O18 ceramics have been synthesized by solid state reaction. The ferroelectric transition of the compounds was studied by differential scanning calorimetry, high-temperature x-ray diffraction, and temperature-dependent dielectric measurements. Two solid-state structural transitions were observed in both compounds, one is the orthorhombic↔tetragonal transition (ferroelectric transition) at 1021 K for Bi5Ti3FeO15 and 973 K for Bi6Ti3Fe2O18, and the other is accompanied by an abrupt lattice expansion of the tetragonal phase at about 1110 K for Bi5Ti3FeO15 and about 1090 K for Bi6Ti3Fe2O18.

A multi-channel readout electronics system for GEM and MICROMEGAS has been developed. It consists of a front-end ASIC, a multi-channel ADC and a FPGA to sample the signal waveforms in real time. The gain of the front-end ASIC can be programmable from 1 mV/fC to 19 mV/fC and the output pulse width can be adjusted from 200 ns to 800 ns. The ENC is measured to be below 2000 e for Cin < 20 pF and below 5000 e for Cin < 60 pF. Detailed circuit performance and test results with detectors will be described in this paper.

The influence of Cr-doping on the microstructure and properties of aluminum nitride (AlN) films has been investigated by means of x-ray diffraction, transmission electron microscopy, x-ray absorption near edge structure, piezoelectric force microscopy and x-ray photoelectron spectroscopy. The results indicate that Cr3+ steadily substitutes for Al3+ in AlN wurtzite lattice without any precipitated secondary phase formation. Moderate Cr-doping has a profound influence on the enhancement of (0 0 2) texture and crystallinity of Cr : AlN films. The residual stress for the Cr : AlN films changes from tension to compressive stress with increasing Cr concentration. The Al0.937Cr0.063N film is almost stress-free and has a piezoelectric constant of −7.1 pm V−1 which is 73% higher than that of the undoped AlN film (−4.1 pm V−1). Besides the enhancement of (0 0 2) texture and crystallinity of the Cr : AlN films, the decrease in Al-polarity regions and the resultant increase in the net polarity orientation by Cr-doping also contribute to the increase in AlN piezoelectric response.

Zn1−xVxO films (x = 0, 1.3, 1.9, 2.6, 3.5, 4.3 and 6.2 at%) were prepared on glass substrates via the direct current reactive magnetron co-sputtering method. The microstructure, band gap, photoluminescence and Raman scattering of these films have been systematically investigated. The structural and chemical state characterizations indicate that the crystallinity of Zn1−xVxO films (x 2.6 at%) can be improved by V incorporation into the ZnO wurtzite lattice, but excess V will precipitate as V clusters when x 4.3 at%, resulting in the deterioration of crystal quality. The defects in Zn1−xVxO films (x 2.6 at%) can be suppressed by V doping, which induces the enhancement of the near band edge (NBE) emission. However, when x 4.3 at%, defects adjacent to the V dopant quench the NBE emission. On the other hand, the band gap of the films gradually increases with the increase in V concentration, which is accompanied by the blue shift of the NBE emission. (Some figures in this article are in colour only in the electronic version)

Single-phase samples of Bi(Fe1−xCrx)O3 with x=0, 0.1, and 0.2 were synthesized by a combustion method. X-ray diffraction reveals that the lattice parameters of Bi(Fe1−xCrx)O3 perovskites decrease linearly with the Cr content, indicating that Cr ions substitute for Fe ions to form a solid solution. X-ray photoelectron spectroscopy investigation shows that Cr ions have the Cr3+ valence state in Bi(Fe1−xCrx)O3. The frequency dependence of dielectric constants was investigated at room temperature. Magnetic measurements show hysteresis loops at both 5 and 300K and the substitution of Cr for Fe enhances the magnetization.

Ice accretion on economically valuable and strategically important surfaces poses significant challenges. Current anti-/de-icing techniques often have critical issues regarding their efficiency, convenience, long-term stability, or sustainability. As an emerging ice mitigation strategy, the thin-film surface acoustic wave (SAW) has great potentials due to its high energy efficiency and effective integration on structural surfaces. However, anti-/de-icing processes activated by SAWs involve complex interfacial evolution and phase changes, and it is crucial to understand the nature of dynamic solid-liquid-vapor phase changes and ice nucleation, growth, and melting events under SAW agitation. In this study, we systematically investigated the accretion and removal of porous rime ice from structural surfaces activated by SAWs. We found that icing and de-icing processes are strongly linked with the dynamical interfacial phase and structure changes of rime ice under SAW activation and the acousto-thermally induced localized heating that facilitate the melting of ice crystals. Subsequently, interactions of SAWs with the formed thin water layer at the ice/structure interface result in significant streaming effects that lead to further damage and melting of ice, liquid pumping, jetting, or nebulization.