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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
  • electron-transparent membranes
  • micropump
  • field emission electron source
  • ion source
  • ion mobility spectrometry
应用领域
  • Optoelectronic Information Science and Engineering
机构单位
  • Wroclaw University of Science and Technology
209 条数据
?? 中文（中国） ▾

  • A new asymmetric anthracene derivative with high mobility

    摘要： An asymmetric anthracene derivative (4-HDPA) was designed and synthesized. With the optimization of proper scenario of fabrication process, top-contact thin film devices based on 4-HDPA exhibit mobility as high as 3.59 cm2 V–1 s–1, while its single-crystal devices exhibit mobility as high as 5.12 cm2 V–1 s–1, which is higher than the symmetrical counterpart of 4-HDPA in both single-crystal and thin film devices.

    关键词： organic field-effect transistor (OFET),mobility,asymmetric,anthracene derivative

    更新于2025-09-23 15:23:52

  • Influence of Pendant Group on Mobility of Organic Thin Film Transistor in Correlation with Reorganization Energy of Molecules

    摘要： Charge transport properties of common donor copolymers in organic photovoltaics, poly({4,8-bis[(2-ethylhexyl)oxy]benzo[1,2-b:4,5-b′]dithiophene-2,6-diyl}{3-fluoro-2-[(2-ethylhexyl)carbonyl]thieno[3,4-b]thiophenediyl}) (PTB7) and poly([2,6′-4,8-di(5-ethylhexylthienyl)benzo[1,2-b;3,3-b]dithiophene]{3-fluoro-2[(2-ethylhexyl) carbonyl]thieno[3,4-b]thiophenediyl}) (PTB7-Th), with molecular structures differing only in the pendant group, are studied. This is the first report of field-effect transistor mobility (μFET) of PTB7-Th (0.14 cm2 V?1 s?1) and the highest μFET for PTB7 (0.01 cm2 V?1 s?1). μFET of PTB7-Th is found to be almost one order of magnitude higher than PTB7. To understand the influence of molecular structure on charge transport, hole reorganization energy (λh) is calculated from first-principles. λh of PTB7-Th (≈150 meV) is found to be lower than PTB7 (≈346 meV). Further, the ratio of hopping rate versus square of charge transfer integral calculated from Marcus theory using λh for these systems is found to indicate a higher rate of hole transfer across dimers or homojunction interface for PTB7-Th. These results are supplemented by experimentally determined λ using bulk-heterojunction organic solar cells, where λPTB7-Th≈200 meV and λPTB7≈310 meV follow a similar trend. The effective hole-mobility estimation from BHJ devices correlates well with these λ values. This study provides understanding of charge transport properties via reorganization energy, as a function of pendant group without altering the backbone of the chains.

    关键词： OFET,mobility,reorganization energy,pendant groups

    更新于2025-09-23 15:23:52

  • In Situ Monitoring of Thermal Degradation of CH <sub/>3</sub> NH <sub/>3</sub> PbI <sub/>3</sub> Films by Spectroscopic Ellipsometry

    摘要： High mobility group A2 (HMGA2) is an architectural transcription factor that promotes human colorectal cancer (CRC) aggressiveness by modulating the transcription of target genes. The degradation of p53 is mediated by murine double minute 2 (MDM2) in a proteasome-dependent manner. Here we report that HMGA2 promotes cell cycle progression and inhibits apoptosis in CRC cells in vitro. We also developed an intestinal epithelial cell-specific Hmga2 knock-in (KI) mouse model. It revealed that the Hmga2 KI promoted chemical carcinogen-induced tumorigenesis in the intestine in vivo. In studying the underlying molecular mechanism, we found that HMGA2 formed a protein complex with p53. The tetramerization domain of p53 (amino acids 294–393) and the three AT-hook domains (amino acids 1–83) of HMGA2 were responsible for their direct interaction. We also found that HMGA2 directly bound to MDM2 and the central acidic and zinc finger domains of MDM2 (amino acids 111–360) were required for interaction with HMGA2. Furthermore, our results indicated that HMGA2 promoted MDM2-mediated p53 ubiquitination and degradation. Interestingly, Hmga2 overexpression in Hmga2 KI mice resulted in an increase in the accumulation of ubiquitinated p53. In addition, in two large CRC cohorts, it was demonstrated that high HMGA2 expression was predictive of an adverse outcome in the p53-negative subgroup of CRC patients. In summary, our data have established for the first time a novel mechanism by which HMGA2 functions with p53 and MDM2 to promote CRC progression.

    关键词： high mobility group AT-hook 2,colorectal cancer,p53

    更新于2025-09-23 15:23:52

  • [IEEE 2018 IEEE International Conference on Electron Devices and Solid State Circuits (EDSSC) - Shenzhen (2018.6.6-2018.6.8)] 2018 IEEE International Conference on Electron Devices and Solid State Circuits (EDSSC) - Analysis of 1/f Noise for Organic TFTs Considering Mobility Power-Law Parameter

    摘要： Based on carrier number fluctuation model, 1/f noise is analyzed for organic thin-film transistors (TFTs) at low drain voltage. The carrier mobility is gate-voltage-dependent, and is described by a power-law function. The mobility power-law parameter α determines the relationship between drain current noise power spectral density (PSD) SIDS and drain current IDS, and it is found that SIDS /I 2 DS when α = 1. It is different from the well-known rule for the MOSFETs with the constant carrier mobility: When SIDS /I 2 DS , Hooge’s mobility fluctuation model dominates the 1/f noise.

    关键词： carrier mobility,Thin-film transistor (TFT),analytical model,low frequency noise

    更新于2025-09-23 15:23:52

  • Thermal Analysis of AlGaN/GaN High-Electron-Mobility Transistors with Graphene

    摘要： A thermal analysis of AlGaN/GaN high electron mobility transistors (HEMTs) with Graphene is investigated using Silvaco and Finite Element Method. Two thermal management solutions are adopted; first of all, graphene is used as dissipation material between SiC substrate and GaN buffer layer to reduce thermal boundary resistance of the device. At the same time, graphene is also used as a thermal spread material on the top of the source contacts to reduce thermal resistance of the device. The thermal analysis results show that the temperature rise of device adopting graphene decreases by 46.5% in transistors operating at 13.86 W/mm. Meanwhile, the thermal resistance of GaN HEMTs with graphene is 6.8 K/W, which is much lower than the device without graphene, which is 18.5 K/W. The thermal management solutions are useful for integration of large-scale graphene into practical devices for effective heat spreading in AlGaN/GaN HEMT.

    关键词： AlGaN/GaN,Thermal Management,High-Electron-Mobility Transistors (HEMTs),Graphene

    更新于2025-09-23 15:23:52

  • Asymmetric Pentacenes for Solution-Processed Organic Field-Effect Transistors

    摘要： Background: Symmetrically substituted pentacenes have been traditionally used as semiconductors for solution-processed p-channel Organic Field Effect Transistors (OFETs). The aims of this paper are to introduce asymmetrically substituted pentacenes in the active layer and to examine the impact of the polyaromaticity of the pendant groups on the device characteristics. Methods: Research and online content related to asymmetrically substituted pentacenes is reviewed, the synthesis of the different pentacenes is described and the procedure used to introduce these semiconductors in devices is detailed. Comparison with a reference material is provided. Results: Extension of the polyaromaticity of the pendant group of pentacene greatly contributes to enhance the device performances. Impact of the pendant group on the morphology of the active layer is evidenced by the roughness decreasing with the increase of aromatic ring in the substituent. Conclusion: We demonstrate the extension of the π-conjugation of the aromatic end-group to drastically impact both ON/OFF ratio and charge carrier mobilities, mainly due to various degree of crystal formation characteristics in the film. Best results were obtained with the most extended one, namely the anthracene moiety which showed a mobility comparable to that of the benchmark TIPS-pentacene with OFETs that used hexamethyldisilazane as the gate dielectric passivation layer.

    关键词： solution-process,semiconductor,organic materials,OFET,Mobility,TIPS-pentacene

    更新于2025-09-23 15:23:52

  • An adapted method for analyzing 4H silicon carbide metal-oxide-semiconductor field-effect transistors

    摘要： Silicon carbide (SiC) metal-oxide-semiconductor field-effect transistors (MOSFETs) are key devices for next-generation power electronics. However, accurate determination of device parameters from 3-terminal characteristics is hampered by the presence of interface traps. Here we present a method that, in contrast to previous evaluation schemes, explicitly considers those defects. A well-tractable parametrization of the SiC/SiO2-specific interface trap spectrum is introduced that reflects the body of known data. With this ingredient, we develop an analysis that targets for an accurate determination of device parameters from simple 3-terminal characteristics. For its validation, we investigate MOSFETs with significantly different defect densities. The resulting parameters – charge carrier density, mobility and threshold voltage – are in excellent agreement with Hall effect investigations on the very same devices, avoiding systematic errors inherent to conventional evaluation techniques. With this adapted scheme, 4H-SiC power MOSFETs, even packaged, can be meaningfully characterized, speeding up innovation cycles in energy-saving power electronics.

    关键词： mobility,Silicon carbide,Hall effect,interface traps,threshold voltage,MOSFET

    更新于2025-09-23 15:23:52

  • Native mass spectrometry reveals the conformational diversity of the UVR8 photoreceptor

    摘要： UVR8 is a plant photoreceptor protein that regulates photomorphogenic and protective responses to UV light. The inactive, homodimeric state absorbs UV-B light, resulting in dissociation into monomers, which are considered to be the active state and comprise a β-propeller core domain and intrinsically disordered N- and C-terminal tails. The C terminus is required for functional binding to signaling partner COP1. To date, however, structural studies have only been conducted with the core domain where the terminal tails have been truncated. Here, we report structural investigations of full-length UVR8 using native ion mobility mass spectrometry adapted for photoactivation. We show that, while truncated UVR8 photoconverts from a single conformation of dimers to a single monomer conformation, the full-length protein exists in numerous conformational families. The full-length dimer adopts both a compact state and an extended state where the C terminus is primed for activation. In the monomer the extended C terminus destabilizes the core domain to produce highly extended yet stable conformations, which we propose are the fully active states that bind COP1. Our results reveal the conformational diversity of full-length UVR8. We also demonstrate the potential power of native mass spectrometry to probe functionally important structural dynamics of photoreceptor proteins throughout nature.

    关键词： intrinsically disordered proteins,plant photoreception,UVR8,native mass spectrometry,ion mobility

    更新于2025-09-23 15:23:52

  • Theoretical Investigation on Electron Mobility in AlInGaN/InGaN Heterostructures

    摘要： The dependences of electron mobility in AlInGaN/InGaN heterostructure on the barrier and channel alloy compositions and on temperature are investigated including six scattering processes: acoustic deformation potential (DP) scattering, piezoelectric field (PE) scattering, polar optical phonons (PO) scattering, dislocation impurity (DIS) scattering, interface roughness (IRF) scattering, and alloy disorder (ADO) scattering. The results show that ADO scattering is the most important scattering mechanism, and specifically channel alloy disorder gets severer than barrier alloy disorder except for InGaN channels with very low indium content (near 0) or extremely high indium mole fraction (near 1). The variations of the barrier strain, two-dimensional electron gas (2DEG) density, 2DEG mobility, and conductivity in AlInGaN/In0.04Ga0.96N heterostructure with full barrier alloy composition are summarized. The results indicate that relatively large aluminum content and small indium mole fraction are desired for higher conductivity. By comparing the temperature-dependent transport properties of Al0.83In0.13Ga0.04N/InGaN heterostructures with different InGaN compositions, we find that it is the ADO scattering and PO scattering that determine 2DEG mobility change and the mobility exhibits a weaker dependence on temperature with increasing indium mole fraction in InGaN channel.

    关键词： scattering mechanisms,mobility,temperature,two-dimensional electron gas

    更新于2025-09-23 15:23:52

  • Uniform Cs2SnI6 Thin Films for Lead-Free and Stable Perovskite Optoelectronics via Hybrid Deposition Approaches

    摘要： Herein, we synthesized uniform Cs2SnI6 films by two kinds of hybrid deposition methods by considering volume expansion involved during phase transformations. First, oblique thermal evaporation for CsI followed by SnI4 spin-coating resulted in uniform Cs2SnI6 films free of impurity phases. The rapid expansion (within 10 s of spin-coating) from CsI to Cs2SnI6 (ΔV = 106%) was accommodated by porous CsI films inhibiting crack formation. Excess SnI4 on the Cs2SnI6 after spin-coating was effectively removed by toluene washing without any damages to Cs2SnI6, and optimum deposition parameters were suggested in terms of carrier mobility. Second, annealing CsI with SnI4 vapor at 250 °C and post-annealing in the SnI4 and I2 vapor at 300 °C produced Cs2SnI6 film with complete coverage. The slow reaction (70 min for a complete conversion) provided sufficient time for complete diffusion of SnI4 into CsI without crack formation even with compact CsI. The nonradiative recombination path in Cs2SnI6 was suppressed by post-annealing in the SnI4- and I2-atmosphere, as confirmed from the enhanced photoluminescence.

    关键词： Lead-free perovskite,Cs2SnI6,Electrical mobility,Oblique thermal deposition

    更新于2025-09-23 15:23:52