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oe1(光电查) - 科学论文

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出版时间
  • 2018
研究主题
  • thin-film transistors
  • N2O plasma treatment.
  • amorphous InGaZnO
  • gate-bias stress
  • stability
应用领域
  • Electronic Science and Technology
机构单位
  • Peking University
567 条数据
?? 中文（中国） ▾

  • Influence of thermal annealing on structural and optical properties of RF-sputtered LiTaO <sub/>3</sub> thin films

    摘要： Near stoichiometric ratio lithium tantalate (LiTaO3) thin film possesses unique performance advantages compared with bulk LiTaO3 single crystal in applying in thermal sensors and detectors. Here, LiTaO3 thin film is prepared on Pt/Ti/SiO2/Si(100) substrate by the method of RF magnetron sputtering. The authors conduct research on the structure and optical properties of LiTaO3 thin film under the conditions of annealing temperatures varying from 550 °C to 700 °C. Besides, the authors also study on optical constants of the LiTaO3 thin film which includes refractive indices, extinction coefficients and optical band gap energy by spectroscopic ellipsometry. The results show that optical band gap energy Eg will increase along with the grain size’s increase. Moreover, the results demonstrate that the best annealing temperature is 600 °C. Under the best annealing condition, the obtained refractive index, extinction coefficient k and optical band gap energy Eg is 2.05, 2×10?5 and 3.82 eV, respectively. These values are consistent with that of lithium tantalate single crystal. All results above mentioned proving that lithium tantalate (LiTaO3) thin film prepared by RF magnetron sputtering possesses a good crystallinity and ordered structure.

    关键词： optical constants,lithium tantalate thin film,RF magnetron sputtering,optical band gap Eg

    更新于2025-09-10 09:29:36

  • Effects of ultraviolet photon irradiation and subsequent thermal treatments on solution-processed amorphous indium gallium zinc oxide thin films

    摘要： Effects of exposure to ultraviolet (UV) photons and thermal treatments on solution-processed amorphous indium gallium zinc oxide (a-IGZO) films were investigated by X-ray photoelectron spectroscopy (XPS) and photoluminescence (PL) spectroscopy. As a result, oxygen vacancies obviously become more abundant in the films sintered at 250 or 300 ?C by the exposure to 7.21 eV photons and less abundant by the subsequent thermal treatment at 250 ?C in air. The drain current also clearly becomes smaller in a thin film transistor fabricated using the IGZO film in a manner opposite to the abundance of oxygen vacancies. That is, the drain current becomes smaller by the UV irradiation and returns to the original high value by the subsequent thermal treatment. This indicates that oxygen vacancies act as trapping centers or scattering centers of electrons. In addition, the reversible change of the drain current with the cycle of UV irradiation and the thermal treatment opens the possibility of the use of the IGZO films as a UV sensor.

    关键词： oxygen vacancies,amorphous indium gallium zinc oxide,thin film transistor,UV irradiation,thermal treatment

    更新于2025-09-10 09:29:36

  • Thermal Treatments and Photoluminescence Properties of ZnO and ZnO:Yb Films Grown by Magnetron Sputtering

    摘要： This work is on ZnO and ZnO:Yb (0.3 at%) films prepared on (100) Si substrates by magnetron sputtering and deals with their structural and photoluminescence evolutions upon annealing at different temperatures from 873 to 1173 K during 1 h under N2 atmosphere. The microstructural characterizations reveal that, for both sample series, annealing treatment improves the crystallinity of ZnO of the upper part of the films. However, (002) textured ZnO columnar growth is only observed for ZnO films. For annealing temperatures higher than 973 K, rare earth and Si diffusions toward the film/substrate interface are observed resulting in the appearance of a zinc silicate phase for ZnO films and a composite material made of nanoscale ZnO grains surrounded by an amorphous phase for ZnO:Yb films. In addition, photoluminescence measurements show that Yb doping in ZnO results in a lower integrated photoluminescence intensity compared to that of ZnO films and the photoluminescence response in the visible spectral range is also modified most probably due to the presence of dopant. Furthermore, the PL intensity at 980 nm originating from electronic transitions between 2F5/2 and 2F7/2 levels of Yb3+ ion increased with temperature. At last, the evolutions of the PL emissions with temperature from the ZnO defects are discussed.

    关键词： ZnO,thin film,magnetron sputtering,Yb doping

    更新于2025-09-09 09:28:46

  • Flexible dual-mode SAW strain sensor based on crystalline LiNbO3 thin film

    摘要： This work presents the development of flexible dual-mode surface acoustic wave (SAW) sensor based on single crystalline thin film lithium niobate (TF-LN). Numerical modeling is conducted to investigate the SAW propagation and the effects on strain sensitivity. The dependence of strain sensitivity on angles between the applied strain and SAW propagation direction is analyzed numerically and experimentally, showing that the maximum strain sensitivity is at 45° rather than longitudinal direction. 128° Y-cut TF-LN (~50 μm), obtained by micromachining technique, is utilized as the piezoelectric substrate to fabricate the SAW strain sensors with dual mode, namely Rayleigh mode and thickness shear mode (TSM). The sensor has excellent flexibility and demonstrates remarkable capability for an ultra-wide range strain measurement up to ±3000 με. Temperature effects on resonant frequency and strain sensitivity are investigated in the range of 25 ~ 100 ℃, and similar temperature characteristics are observed for the dual modes. A method of beat frequency between the dual modes is introduced which is able to eliminate the temperature effect on strain sensing, an on-chip temperature influence removing capability. All the results clearly show that this sensor exhibits great potential for applications in flexible electronics and microsystems.

    关键词： dual-mode,temperature cancellation,flexible strain sensor,LiNbO3 thin film,surface acoustic wave

    更新于2025-09-09 09:28:46

  • Superconducting electrode capacitor based on double-sided YBCO thin film for wireless power transfer applications

    摘要： A high-temperature superconducting (HTS) electrode capacitor (HTS capacitor) has been reported for the first time in the form of a superconductor–insulator–superconductor structure. Double-sided HTS thin film might be inherently suitable for the raw material choice of an HTS capacitor. In terms of electrode material, HTS thin film has a much lower surface resistance than normal conductors, and, as a dielectric medium, its substrate generally has a larger dielectric constant but a smaller loss tangent than the dielectric layers of some conventional capacitors. Thus, it is possible to fabricate a high-quality capacitor based on double-sided HTS thin film. This type of HTS capacitor could play a role in wireless power transfer (WPT) technology, since the WPT efficiency depends on the quality factors of both the coil and capacitor. Numerous studies have been performed to optimize the WPT system with HTS coil. In contrast, we develop an HTS capacitor based on double-sided YBCO film for WPT applications and investigate its effect on the WPT system. It is found that the HTS capacitor can provide a high quality factor, enhance WPT efficiency, and work normally with an HTS coil at 77 K, avoiding the dilemma between an HTS coil and a normal capacitor.

    关键词： superconducting electrode capacitor,double-sided YBCO thin film,wireless power transfer

    更新于2025-09-09 09:28:46

  • Tunable multi-color luminescence and white emission in lanthanide ion functionalized polyoxometalate-based metal–organic frameworks hybrids and fabricated thin films

    摘要： In this paper, luminescent hybrid material systems are prepared with porous polyoxometalate-based metal-organic framework (POM-based MOF)[La(H2O)4(pdc)]4}[SiMo12O40]$2H2O (1) through the introduction of lanthanide ions (Ln3+, Ln = Eu, Tb, Sm, Dy, Eu/Tb, Dy/Eu) by a solvothermal approach. The POM-based MOF serves as a host for protecting the luminescence of Ln3+ cations. The structure, thermal stability, ultraviolet absorption and visible light emission of the target hybrid materials are determined with powder X-rays diffraction patterns (PXRD), Fourier transform infrared spectra (FTIR), thermal-gravimetric analysis (TGA), inductively coupled plasma-mass spectrometry (ICP-MS) analysis, energy dispersive spectrometer (EDS), ultraviolet visible diffusion reflections spectra (UV-vis DRS) and especially luminescence spectra. The final luminescence of the Ln3+ hybrids can be adjusted by changing the composition of Ln3+ cations or converting the excitation wavelengths of them. Among [La0.95Dy0.045Eu0.005(H2O)4(pdc)]4}[SiMo12O40]$2H2O (Dy3+/Eu3+@1) emits white luminescence under the excitation at 295 nm and the Commission Internationale de L'Eclairage (CIE) chromaticity coordinate of it is (0.361, 0.3408). Moreover, we manufacture POM-based MOF thin films by using ethyl methacrylate (EMA) to assemble the POM-based MOF on a quartz plate as substrate. The hybrid thin films based on {La0.95Eu0.05(H2O)4(pdc)]4}[SiMo12O40]$2H2O (Eu3+@1) and La0.95Eu0.04Tb0.01(H2O)4(pdc)]4}[SiMo12O40]$2H2O (Eu3+/Tb3+@1) can also achieve white-light. The CIE chromaticity coordinates of them are (0.3425, 0.2548) and (0.3857, 0.3377), respectively.

    关键词： Thin film,Lanthanide functionalization,Photofunctional hybrid material,Polyoxometallate based metal-organic frameworks,Luminescence

    更新于2025-09-09 09:28:46

  • Mg doped CdO thin films grown on glass substrate by spray pyrolysis method

    摘要： The undoped and various magnesium (Mg) doped cadmium oxide (CdO) thin films were synthesized by spray pyrolysis technique. Structural, optical and morphological examinations of the samples were carried out via various instruments. X-ray diffraction (XRD) and Raman spectroscopic measurements of the samples were performed to obtain structural properties. Ultraviolet (UV)-visible and photoluminescence (PL) spectroscopy measurements as well as scanning electron microscopy (SEM) were employed to characterize optical and morphological properties of the undoped and Mg doped CdO thin film. XRD measurements revealed that both the undoped and Mg doped CdO thin films demonstrated a cubic structure and had preferential orientations along the (200) plane. In the Raman spectrum, it was observed that the peak (266 cm?1) of the first peak belonging to the CdO thin film disappeared and the second main peak (908 cm?1) shifted to higher energies with the Mg dopant. As a result of the absorbance measurements, the band range of the samples showed a shift of the band gap from 2.15 eV to 2.43 eV with the Mg dopant, and the Burstein-Moss effect indicated a shift to gray scale and decreased from 67% to 59% in transmittance measurements. The PL results exhibited that both the undoped and Mg doped CdO thin films had a UV emission of 394 nm (3.15 eV), blue emission of 434 nm (2.86 eV), blue-yellow emission of 540 nm (2.30 eV), 735 nm (1.69 eV) and emission of 782 nm (1.59 eV). The SEM measurements indicated that the CdO thin films changed from pyramidal structures to random shape with Mg dopant.

    关键词： optical properties,Mg dopant,CdO thin film

    更新于2025-09-09 09:28:46

  • THz Sensing With Anomalous Extraordinary Optical Transmission Hole Arrays

    摘要： Subwavelength hole array (HA) metasurfaces support the so-called extraordinary optical transmission (EOT) resonance that has already been exploited for sensing. In this work, we demonstrate the superior performance of a different resonant regime of HA metasurfaces called anomalous EOT, by doing a thorough numerical and experimental study of its ability in thin-film label-free sensing applications in the terahertz (THz) band. A comprehensive analysis using both the regular and anomalous EOT resonances is done by depositing thin layers of dielectric analyte slabs of different thicknesses on the structures in different scenarios. We carry out a detailed comparison and demonstrate that the best sensing performance is achieved when the structure operates in the anomalous EOT resonance and the analyte is deposited on the non-patterned side of the metasurface, improving by a factor between 2 and 3 the results of the EOT resonance in any of the considered scenarios. This can be explained by the comparatively narrower linewidth of the anomalous EOT resonance. The results presented expand the reach of subwavelength HAs for sensing applications by considering the anomalous EOT regime that is usually overlooked in the literature.

    关键词： metasurface,thin film,anomalous EOT,sensing,terahertz

    更新于2025-09-09 09:28:46

  • Multioutputs single-stage gate driver on array with wide temperature operable thin-film-transistor liquid-crystal display for high resolution application

    摘要： A hydrogenated amorphous silicon (a‐Si:H) thin‐film transistor (TFT) gate driver with multioutputs (eight outputs per stage) for high reliability, 10.7‐inch automotive display has been proposed. The driver circuit is composed of one SR controller, eight driving TFTs (one stage to eight outputs) with bridging TFTs. The SR controller, which starts up the driving TFTs, could also prevent the noise of gate line for nonworking period. The bridging TFT, using width decreasing which connects between the SR controller and the driving TFT, could produce the floating state which is beneficial to couple the gate voltage, improves the driving ability of output, and reaches consistent rising time in high temperature and low temperature environment. Moreover, 8‐phase clocks with 75% overlapping and dual‐side driving scheme are also used in the circuit design to ensure enough charging time and reduce the loading of each gate line. According to lifetime test results, the proposed gate driver of 720 stages pass the extreme temperature range test (90°C and ?40°C) for simulation, and operates stably over 800 hours at 90°C for measurement. Besides, this design is successfully demonstrated in a 10.7‐inch full HD (1080 × RGB×1920) TFT‐liquid‐crystal display (LCD) panel.

    关键词： thin film transistor (TFT),wide temperature,high reliability,gate driver,amorphous silicon (a‐Si)

    更新于2025-09-09 09:28:46

  • Distributed Strain Sensing Using Electrical Time Domain Reflectometry With Nanocomposites

    摘要： The objective of this study is to validate distributed strain sensing using electrical time domain reflectometry (ETDR) with multi-walled carbon nanotube (MWCNT)-based thin film sensing elements. The proposed ETDR sensor composed of two types of transmission lines: parallel-wire-type transmission line and parallel-plate-type transmission line with MWCNT-based sensing elements. The hypothesis was that the greater strain-induced impedance changes of the nanocomposite would enhance ETDR sensing performance. In this paper, four different types of ETDR sensing elements were subjected to one-cycle uniaxial tensile strains to validate strain sensing. Three sensing elements were then integrated in an ETDR setup, and strain patterns were applied for validating their distributed strain sensing behavior.

    关键词： transmission line,Carbon nanotubes,thin film,strain sensing,electrical time domain reflectometry

    更新于2025-09-09 09:28:46