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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
175 条数据
?? 中文（中国） ▾

  • Glass-forming derivatives of 2-cyano-2-(4H-pyran-4-ylidene) acetate for light-amplification systems

    摘要： A series of 2-cyano-2-(4H-pyran-4-ylidene) acetate derivatives with triphenyl and 9H-carbazole moieties were synthesized and investigated, mostly for potential applications in organic solid state lasers. Synthesized compounds show remarkable amorphous film formation ability, tunable thermal properties (thermal stability varies from 190 °C to 387 °C and glass transition temperature from 94 °C up to 141 °C) with light absorption from 400 nm to 600 nm and photoluminescence from 600 nm up to 800 nm. Dyes with incorporated mono-styryl-electron donating fragment (KTB, KTBC and KTB3K) showed higher photoluminescence quantum yield (PLQY) (from 16% up to 23%), significantly lower amplified spontaneous emission (ASE) excitation threshold values (24–52 μJ/cm2) in pure thin films comparing to bis-styryl- electron donating fragment containing molecules (Bis-K4C, Bis-K5C and Bis-K4CK) with PLQY of 5–7% and ASE excitation threshold between 165 and 223 μJ/cm2. Some of the investigated KTB-type laser dyes could be perspective materials for organic lasers as well as for laser technology investigation and applications.

    关键词： 4H-pyran-4-ylidene,Laser dyes,2-cyanoacetates,Amplified spontaneous emission,Amorphous materials

    更新于2025-09-23 15:21:21

  • Influence of Passivation Layers on Positive Gate Bias-Stress Stability of Amorphous InGaZnO Thin-Film Transistors

    摘要： Passivation (PV) layers could effectively improve the positive gate bias-stress (PGBS) stability of amorphous InGaZnO (a-IGZO) thin-film transistors (TFTs), whereas the related physical mechanism remains unclear. In this study, SiO2 or Al2O3 films with different thicknesses were used to passivate the a-IGZO TFTs, making the devices more stable during PGBS tests. With the increase in PV layer thickness, the PGBS stability of a-IGZO TFTs improved due to the stronger barrier effect of the PV layers. When the PV layer thickness was larger than the characteristic length, nearly no threshold voltage shift occurred, indicating that the ambient atmosphere effect rather than the charge trapping dominated the PGBS instability of a-IGZO TFTs in this study. The SiO2 PV layers showed a better improvement effect than the Al2O3 because the former had a smaller characteristic length (~5 nm) than that of the Al2O3 PV layers (~10 nm).

    关键词： thin-film transistor (TFT),positive gate bias stress (PGBS),passivation layer,characteristic length,amorphous InGaZnO (a-IGZO)

    更新于2025-09-23 15:21:21

  • Li Permeability Increase in Nano-Sized Amorphous Silicon Layers

    摘要： Li permeation through nano-sized amorphous Si layers is investigated for temperatures up to 500°C (773 K) as a function of layer thickness between 12 and 95 nm. For the experiments the Si layers are embedded between 6Li and 7Li isotope enriched oxide based Li reservoirs and the thermally induced isotope exchange (through silicon layers and interfaces) is analyzed by Secondary Ion Mass Spectrometry in order to calculate Li permeabilities. The experiments reveal that the interface between silicon and the Li metal oxide does not hinder Li permeation and Li diffusion in silicon controls the overall process. The determined Li permeability increases drastically by orders of magnitude with decreasing silicon layer thickness, accompanied by a decrease in the activation enthalpy of Li permeation. These results can be explained by a gradual transition of trap-limited slow Li diffusion at high silicon thicknesses to interstitial fast Li diffusion at low Si thicknesses.

    关键词： Li permeation,nano-sized layers,Li permeability,trap-limited diffusion,amorphous silicon,Secondary Ion Mass Spectrometry,isotope exchange,interstitial diffusion

    更新于2025-09-23 15:21:21

  • Efficient broadband light absorption in thin-film a-Si solar cell based on double sided hybrid bi-metallic nanogratings

    摘要： Thin film solar cells (TFSCs) suffer from poor light absorption due to their small thickness, which limits most of their practical applications. Surface plasmons generated by plasmonic nanoparticles offer an opportunity for a low-cost and scalable method to optically engineer TFSCs. Here, a systematic simulation study is conducted to improve the absorption efficiency of amorphous silicon (a-Si) by incorporating double sided plasmonic bi-metallic (Al–Cu) nanogratings. The upper pair of the gratings together with an antireflection coating are responsible for minimizing the reflection losses and enhancing the absorption of low wavelength visible light spectrum in the active layer. The bottom pairs are accountable for increasing the absorption of long wavelength photons in the active layer. In this way, a-Si, which is a poor absorber in the long wavelength region, is now able to absorb broadband light from 670–1060 nm with an average simulated absorption rate of more than 70%, and improved simulated photocurrent density of 22.30 mA cm?2, respectively. Moreover, simulation results show that the proposed structure reveals many other excellent properties such as small incident angle insensitivity, tunability, and remarkable structural parameters tolerance. Such a design concept is quite versatile and can be extended to other TFSCs.

    关键词： amorphous silicon,Thin film solar cells,plasmonic nanoparticles,bi-metallic nanogratings,light absorption

    更新于2025-09-23 15:21:01

  • High-performance amorphous BeZnO-alloy-based solar-blind ultraviolet photodetectors on rigid and flexible substrates

    摘要： In this study, the bandgap of ternary alloy BeZnO was modulated to make the material applicable to solar-blind ultraviolet (UV) radiation detection. This was done by preparing amorphous films with high Be doping contents on rigid c-sapphire and flexible polyethylene terephthalate (PET) and polyethylene naphthalene (PEN) substrates. After depositing a pair of parallel Al electrodes, amorphous BeZnO-alloy-based solar-blind UV photodetectors (PDs) with peak responsivity occurring at around 230 nm were constructed and their cut-off wavelengths are less than 284 nm. The PDs constructed on three substrates exhibit extremely low dark currents of 58.7 pA, 2.9 pA, and 1.8 pA, respectively. Time-dependent photoresponse cycling confirmed devices reproducible, and sensitive to solar-blind UV radiation. More importantly, the devices exhibited fast response speeds with rise times of approximately 40 ms and particularly fast recovery speeds with decay times of approximately 10 ms. Our research provides a method of constructing high-performance PDs on various substrates. And constructing amorphous solar-blind UV PDs on flexible substrate in this work is expected to be guiding significance to the design of PDs with deformability.

    关键词： Amorphous BeZnO alloy,Fast recovery speed,Solar blind photodetectors,Flexible substrate,High Be content

    更新于2025-09-23 15:21:01

  • Laser-induced graphitized periodic surface structure formed on tetrahedral amorphous carbon films

    摘要： Femtosecond laser-induced periodic surface structure (LIPSS), graphitization and swelling observed on ultra-hard, hydrogen-free tetrahedral amorphous carbon (ta-C) films are examined and compared with those on hydrogenated amorphous carbon (a-C:H) films, nitride films, and glassy carbon plates. The threshold fluence for LIPSS formation on ta-C is approximately twice as high as that for other specimens, and the LIPSS period Λ near the threshold is very fine at ca. 80 nm. Λ gradually increases with increasing fluence, and rapidly increases to ca. 600 nm at a high fluence. The ablation rate also increases rapidly at this fluence. In addition, ta-C and a-C:H are graphitized by irradiation and expand in volume. The surface layer of ta-C film changes to nanocrystalline graphite as the fluence increases and the crystallinity is improved; however, at higher fluence, the crystallinity deteriorates suddenly similar to that at low fluence. At high fluence, the rapid increase in Λ and the ablation rate, and the sudden deterioration in crystallinity are determined as common phenomena for these disordered carbons. LIPSS formation and swelling over a large area by scanned spot irradiation produces submicron height flat hills with conductivity and surface functionality on the insulating surface.

    关键词： Graphitization,Swelling,Laser-induced periodic surface structure,Femtosecond-laser processing,Nanocrystalline graphite,Tetrahedral amorphous carbon

    更新于2025-09-23 15:21:01

  • Influence of Focused Pulsed Laser Radiation on the Properties of Amorphous FeSi6B16 Metal Alloy

    摘要： The effect of focused pulsed laser radiation (number of pulses and power density) on an amorphous FeSi6B16 metal film is studied. The states of the alloy before and after laser irradiation are analyzed using methods of atomic force microscopy, X-ray photoelectron spectroscopy, X-ray diffraction, and microhardness measurements. Focused laser radiation in any exposure mode is established to cause high-temperature heating of the surface of an amorphous alloy in the irradiation zone. The result of such heating is melting of the material surface and propagation of the heat wave front from the strongly heated surface to its inner layers, which induces the redistribution of elements in the Fe–Si–B system, a change in the structure, and an increase in the microhardness.

    关键词： microhardness,nonequilibrium state,X-ray photoelectron spectroscopy,atomic-force microscopy,surface,laser radiation,amorphous alloys

    更新于2025-09-23 15:21:01

  • Electroluminescence from amorphous GIZO/p-GaN heterojunction light-emitting diodes

    摘要： The electroluminescence from the amorphous gallium-indium-zinc oxide (a-GIZO)/p-GaN heterojunction light-emitting diodes (LEDs) were demonstrated. The heterojunction LEDs showed a current flow under both forward and reverse bias voltages. The light emissions were observed at around 410 nm (originating from p-GaN) and ~450–800 nm (originating from interfacial layer and/or from a-GIZO), which were particularly pronounced under reverse bias condition. As a result, the standard white light with the chromaticity coordinate of (0.2899, 0.3034) was obtained.

    关键词： Light emitting diode,Gallium-indium-zinc oxide,Heterojunction,Amorphous

    更新于2025-09-23 15:21:01

  • Optimization of laser-patterning process and module design for transparent amorphous silicon thin-film module using thin OMO back electrode

    摘要： Transparent hydrogenated amorphous silicon thin-film solar modules are fabricated using oxide-metal-oxide (OMO) electrodes as the back electrode for building-integrated photovoltaic applications. The outer aluminum-doped zinc oxide and inner silver layers constitute a thin OMO electrode (~110 nm thick), exhibiting a sheet resistance of 6.8 Ω/□ and an average transmittance of ~88% in the visible range of 400–800 nm. The external quantum efficiency and average transmittance of the cell were investigated for the absorber-layer thickness using the finite-difference time-domain method, and it was found that the optical loss in the cell was mainly due to the absorption of the front electrode in the ultra-violet region and free-carrier absorption of the OMO in the infrared region. Fabrication issues are introduced for a 532 nm short-pulse high-power laser patterning process for transparent modules with thin OMO electrodes. Optimization of the laser power for the P2 and P3 laser processes is demonstrated by observing the profiles and measuring the shunt resistance of the laser-patterned edges. Furthermore, the cell width is optimized based on an equivalent circuit model using PSpice simulation. The highest module efficiency and average transparency achieved in the range of 500–800 nm were 5.6% and 15.2%, respectively. The short-circuit current density, fill factor, and open-circuit voltage per cell of the module were found to be 10.8 mA/cm2, 62.7%, and 0.830 V, respectively.

    关键词： Laser patterning,Transparent amorphous silicon photovoltaic,Equivalent circuit,Building integrated photovoltaic,Cell geometry,Oxide-metal-oxide electrode

    更新于2025-09-23 15:21:01

  • Transparent Thin-Film Silicon Solar Cells for Indoor Light Harvesting with Conversion Efficiencies of 36% without Photo-degradation

    摘要： With the development of the Internet of Things (IoT), indoor photovoltaics are attracting considerable interest owing to their potential to benefit various IoT-related fields. Therefore, this study investigates the use of transparent hydrogenated amorphous silicon (a-Si:H) solar cells for a broad range of applications, including indoor light harvesting. High gap triple-layers were employed in the a-Si:H solar cells to obtain a high shunt resistance and high short-circuit current, JSC, and open-circuit voltage, VOC, under indoor illumination. Additionally, multiple color-adjusting layers were added without noticeable costs to the conversion efficiency. The maximum efficiency of 36.0% was obtained at a transmittance of 20.44% under white LED light (3,000 lx and 0.92 mW cm-2). Furthermore, the fabricated transparent solar cells show excellent long-term performance, sustaining over 99% of original efficiency under continuous indoor light illumination for 200 h. These cells could accelerate the progress of energy harvesting in IoT applications and facilitate the construction of integrated photovoltaics.

    关键词： amorphous silicon solar cells,thin film silicon solar cells,transparent solar cells,indoor photovoltaics,colored solar cells

    更新于2025-09-23 15:21:01