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Amorphous indium gallium zinc oxide is a popular semiconductor candidate for amorphous oxide semiconductor thin-film transistors in the field of flat-panel display. However, the existence of gallium component restricts the enhancement of mobility dramatically. In this study, we report a new praseodymium (Pr) dopant as a stabilizer in amorphous indium zinc oxide semiconductor (IZO) with high mobility and stability. Meanwhile, the PrIZO TFTs were fabricated to investigate the effects of Pr on electrical properties, stability and aging effect. The optimal PrIZO TFT exhibited a desired performance with a saturation mobility (μsat) of 25.8/32.6 cm2 V−1 s−1, an Ion/Ioff ratio of 3.5 × 107/5.4 × 107, a subthreshold swing value of 0.14/0.13 V dec−1 and a threshold voltage (Vth) of 2.9/2.1 V, respectively, before and after an air environment storage period of 90 days without passivation layer, which exhibits lower sensitivity of the channel region to oxygen/moisture from the atmosphere than IZO TFT. XRD analysis revealed that the Pr dopant had no effect on the amorphous state of IZO thin film with annealing up to 400 °C. XPS analyses suggested that the fraction of oxygen vacancy subpeak decreased significantly with Pr incorporated into IZO. The μ-PCD decay analyzation and the subgap density of states indicate that acceptor-like trap states induced by Pr ions lead to the suppression of ambient-induced excess carrier in conduction band. This work is anticipated to provide a kind of reliable stabilizer for amorphous oxide semiconductor without deteriorating mobility significantly. [ABSTRACT FROM AUTHOR]

In this work, a thin film transistor (TFT) with Zr-doped aluminum-zinc-tin oxide (Zr-AZTO) semiconductor as active layer was investigated. The Zr-AZTO thin films were co-sputtered by ZrO2 and AZTO targets (RF-Sputter) in Ar, and annealed at 350 °C in air atmosphere. With the discharge power of AZTO increasing from 100 W to 120 W, the content of Zr element decreases from 0.63 ± 0.01 at.% to 0.34 ± 0.01 at.%, and the oxygen vacancy decreases from (19.0 ± 0.1)% to (17.3 ± 0.8)%. The results of Zr-AZTO thin film show that the main factor is the co-sputter power of ZrO2 target. With the co-sputter power of ZrO2 increasing from 15 W to 45 W, the content of Zr element increases from 0.63 ± 0.01 at.% to 2.79 ± 0.01 at.%, the content of oxygen vacancy decreases from (19.0 ± 0.1)% to (14.1 ± 0.1)%, Eg increases from 2.76 eV to 2.86 eV, and the root mean square (RMS) roughness firstly decreases from 0.402 nm to 0.387 nm and then increases to 0.490 nm. The Micro Wave Photo Conductivity Decay (μ-PCD, LTA-1620SP) was used to measure the quality of Zr-AZTO thin film and the mean peak and D value decreases from 139.3 mV to 80.9 mV and from 1.54 to 0.77 as the co-sputter power of ZrO2 increases from 15 W to 45 W, which means it has highest localized states and defects in high ZrO2 co-sputter power. The devices prepared at 15 W (ZrO2)/100 W (AZTO) co-sputter show a best performance, with a μsat of 8.0 ± 0.6 cm2/(V∙S), an Ion/Ioff of (2.01 ± 0.34) × 106, and a SS of 0.18 ± 0.03 V/dec. The device of Sample B has a 0.5 V negative shift under −20 V NBS and 9.6 V positive shift under 20 V PBS. [ABSTRACT FROM AUTHOR]

The structural, optical, and electrical properties of Si‐doped SnO2 (STO) films were investigated in terms of their potential applications for flexible electronic devices. All STO films were amorphous with an optical transmittance of ~90%. The optical band gap was widened as the Si content increased. The Hall mobility and carrier density were improved in the SnO2 with 1 wt% Si film, which was attributed to the formation of donor states. Si (1 wt%) doped SnO2 thin‐film transistor exhibited a good device performance and good stability with a saturation mobility of 6.38 cm2/Vs, a large Ion/Ioff of 1.44 × 107, and a SS value of 0.77 V/decade. The device mobility of a‐STO TFTs at different bending radius maintained still at a high level. These results suggest that a‐STO thin films are promising for fabricating flexible TFTs. [ABSTRACT FROM AUTHOR]

High-quality (001) oriented epitaxial 0.9BiFeO 3 –0.1TbMnO 3 thin films were grown on La 2/3 Sr 1/3 MnO 3 and SrRuO 3 buffered SrTiO 3 substrate using pulsed laser deposition. X-ray diffraction showed that the films are single-phase perovskite without secondary impurity phases. Domain structures and upward ferroelectric self-poling phenomenon were distinctly observed in both films with compressive epitaxial strains. Furthermore, the upward self-poling disappears in polycrystalline 0.9BiFeO 3 –0.1TbMnO 3 thin film on Pt/TiO 2 /SiO 2 /Si substrates. Through local switching spectroscopy measurements, the evidence of enhanced ferroelectric switching and piezoelectric response characteristics have been provided. [ABSTRACT FROM AUTHOR]

Abstract: Heat recovery of air ventilation is a means of energy conversation in buildings. In the present paper, a plastic film heat recovery ventilator that works under cross-flow mode was developed. The thin film vibrates when airflow passes through the channels, which enhances heat exchange performance. Experiments, as well as theoretical analyses, were carried out to study the performance of such a unit. Results show that the effectiveness of the heat exchanger varies from 0.65 to 0.85 with airflow rate and the pressure drop is less than 20.0 Pa. Film vibration induced by airflow can improve heat transfer. The extent of the enhancement is proportional to film vibration intensity that increases with airflow rate while decreases with film thickness. [ABSTRACT FROM AUTHOR]

Solution-processed indium oxide is an ideal transparent semiconductor material with wide band gap. Zirconium is an element characterized by a strong binding ability to oxygen which can inhibit the formation of oxygen vacancies and reduce the surface defect state. In this paper, zirconium doped indium oxide (InxZryO) thin films were prepared by the solution method, with indium oxide being doped with zirconium in order to tune the relative number of oxygen vacancies. The influence of the Zr doping concentration and the post-annealed temperature on the properties of the InxZryO thin films was investigated. The results show that the doping process improves the crystallinity and relative density of the obtained films. A novel nondestructive method named microwave photoconductivity decay (μ-PCD) was used to evaluate the quality of InxZryO thin films by simply measuring their response under laser irradiation. The relative number of oxygen vacancies and the minority carrier concentration achieved minimum values at 10 at.% Zr doping concentration. Furthermore, InxZryO thin films with optimal properties from an electrical point of view were obtained at 10 at.% Zr doping concentration, annealed at 400 °C. Characterized by an average transmittance above 90% in the visible range, the obtained InxZryO thin films can be used as active layer materials in the fabrication of high-performance thin film transistor (TFT) devices. [ABSTRACT FROM AUTHOR]

Tungsten doped stannic oxide transparent conductive thin films (W-doped SnO 2) have been prepared via a solution process. We use stannous chloride, preoxotungstic acid (PTA), hydrogen peroxide and anhydrous ethanol to prepare precursor solution which is stable and colorless. By investigating the effects of tungsten doping ratio and annealing temperature on properties of tungsten doped stannic oxide films, it is found that the amounts of pores on surface can be reduced by increasing annealing temperature. Amorphous SnO 2 begins to transform into crystalline SnO 2 when annealed at 300 °C. The resistivity of 2 at.% W-doped SnO 2 achieves 2.94 × 10−2 Ω cm annealed in air at 500 °C. The transmittance of W-doped SnO 2 films (around 87%) is better than that of pure SnO 2 films (around 83%) in visible range contrasted with blank quartz glass. The optical band gaps of both doped and pure SnO 2 films are over 3.7 eV. • The preoxotungstic acid is used as the dopant for preparing W-doped SnO 2 film. • Adding H 2 O 2 to achieve uniform dissolution of preoxotungstic acid in precursor. • Introducing W6+ into SnO 2 lattice enhances the transmittance and conductivity. • The transmittance of W-doped SnO 2 films is around 87%. • The most efficient doping ratio is 2 at.%. [ABSTRACT FROM AUTHOR]

We developed a new type of lead-free ferroelectric film: Ba(Ti 0.89 Sn 0.11 )O 3 (BTS) with a chemical constituent at its quasi-quadruple point in the phase diagram of BaTiO 3 – x BaSnO 3 . The BTS film was prepared on Pt(1 1 1)/Ti/SiO 2 /Si(1 0 0) substrate by means of the sol–gel method. The results show that the as-prepared BTS thin film has a perovskite structure with preferred (1 1 0) orientation; a highly converse piezoelectric coefficient of d 33 ∼135 pm/V; and dielectric permittivity and dielectric loss of ∼2000 and ∼0.04, respectively, indicating that this new type of lead-free BTS film can probably be used to replace the conventional BaSrTiO 3 and PbZrTiO 3 films. [ABSTRACT FROM AUTHOR]

In this paper, bottom-gate inverted-staggered Ga doped ZnO (GZO) thin film transistors were fabricated by pulsed laser deposition (PLD) at room temperature, and all of results demonstrated that the oxygen pressure has a huge effect on the electrical properties of the device during the preparation of the active layer. As the oxygen pressure increases from 0 Pa to 1.6 Pa, the performances of the TFTs increase first and then decrease. And GZO-TFTs exhibit the best properties with a μ sat of 12.32 cm2/V·s, an I on /I off of 9.17 × 106, a V th of 4.93 V, and a SS of 1.53 V/decade when oxygen pressure is 1.0 Pa. The GZO films were characterized by XPS, XRD, AFM to investigate this phenomenon. The XPS spectra of O 1s and Ga 2p indicated that moderate oxygen can improve the quality of GZO films due to the filled oxygen vacancies, but excess oxygen will bring out the receptor complexes and weaken the performance of TFTs. Furthermore, the best GZO film is amorphous and has a low roughness of 0.78 nm. GZO-TFT has a great potential in the large-area preparation. • Thin film transistors have been prepared by PLD at room temperature with Ga doped ZnO (GZO) active layer. • As the oxygen pressure increases, the performance of the TFT rises first and then decreases. • The properties of GZO films are characterized by a series of methods in order to to explore the mechanism of oxygen pressure. • The active layer is amorphous and has a low roughness of 0.78 nm. [ABSTRACT FROM AUTHOR]