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Pulsed laser deposited Al-doped ZnO thin films for optical applications

Recent advances in oxide thermoelectric materials and modules

Organic-inorganic halide perovskite (OIHP) compounds are very interesting materials for device application in, for example, solar cells, electro-optics, and electronic circuits. In this report, we ...

Enhanced Crystallinity in Organic–Inorganic Lead Halide Perovskites on Mesoporous TiO2 via Disorder–Order Phase Transition

Effect of annealing temperature on the structure and optical properties of In-doped ZnO thin films

Improved thermoelectric properties of Aluminum Zinc Oxide (AZO) thin films deposited by radio frequency (RF) and pulsed Direct Current (DC) magnetron sputtering at room temperature are reported. In both techniques films were deposited using sintered and non-sintered targets produced from nano-powders. It is confirmed that both the Al doping concentration and film thickness control the thermoelectric, optical and structural properties of these films. Seebeck coefficients up to −134 μV K−1 and electrical conductivities up to 4 × 104 (Ω m)−1 lead to power factors up to 4 × 10−4 W mK−2, which is above the state-of-the-art for similar materials, almost by a factor of three. The thermoelectric I–V response of an optimized AZO element with a planar geometry was measured and a maximum power output of 2.3 nW, for a temperature gradient of 20 K near room temperature, was obtained. Moreover, the low thermal conductivity (<1.19 W mK−1) yields a ZT value above 0.1. This is an important result as it is at least three times higher than the ZT found in the literature for AZO, at room temperature, opening new doors for applications of this inexpensive, abundant and environmental friendly material, in a new era of thermoelectric devices.

Transparent aluminium zinc oxide thin films with enhanced thermoelectric properties

In this study, high quality of Al-doped ZnO (AZO) thin films were deposited at different oxygen argon ratio by direct current (DC) reactive magnetron sputtering using a Zn target (99.99%) containing Al of 1.5%. The obtained films were characterized and analyzed by X-ray diffraction (XRD) and ultraviolet–visible and infrared light spectrophotometer. The electrical properties had been investigated by van der Pauw method. It was also found that oxygen argon (O 2 /Ar) ratio had great influence on the properties. The results show that AZO thin films are polycrystalline with a preferred (0 0 2) orientation. The film stress increases with increasing O 2 /Ar ratio. The lowest resistivity of 1.306×10 −3  Ω cm was obtained for the AZO thin films prepared at O 2 /Ar ratio of 0.3/27. Hall mobility decreases with increasing the O 2 /Ar ratio. With increasing O 2 /Ar ratio, the transmittance of the AZO thin films has no evident changes. There is a strong absorption in the ultraviolet region. The optical absorption edge is found to shift to the longer wavelength with the increase of O 2 /Ar ratio. The measurements show that there is a striking Seebeck effect in the AZO thin films, and their thermoelectromotive force is linearly increased with increasing temperature difference (Δ T ). With increasing O 2 /Ar ratio and resistance of samples, thermoelectric power (TEP) decreases.

Influence of oxygen argon ratio on the structural, electrical, optical and thermoelectrical properties of Al-doped ZnO thin films

A new two-dimensional material B2S2 has been successfully synthesized for the first time and validated using first-principles calculations, with fundamental properties analyzed in detail. B2S2 has a similar structure as transition-metal dichalcogenides (TMDs) such as MoS2, and the experimentally prepared free-standing B2S2 nanosheets show a uniform height profile lower than 1 nm. A thickness-modulated and unique oxidation-level dependent band gap of B2S2 is revealed by theoretical calculations, and vibration signatures are determined to offer a practical scheme for the characterization of B2S2. It is shown that the functionalized B2S2 is able to provide favorable sites for lithium adsorption with low diffusion barriers, and the prepared B2S2 shows a wide band photoluminescence response. These findings offer a feasible new and lighter member for the TMD-like 2D material family with potential for various aspects of applications, such as an anode material for Li-ion batteries and electronic and optoelectronic devices.

Experimental Realization and Computational Investigations of B2S2 as a New 2D Material with Potential Applications.

A highly-stable new structural phase of monoelemental two-dimensional boron sheet is discovered. Such new material is acquired by removing the metal atom layers from quasi-layered boride material AlMgB14, inspired by...

S.J. Feng

Papers

Influence of oxygen argon ratio on the structural, electrical, optical and thermoelectrical properties of Al-doped ZnO thin films

Experimental Realization and Computational Investigations of B2S2 as a New 2D Material with Potential Applications.

A novel highly-stable two-dimensional boron phase with promising potentials in the energy fields