修车大队一品楼qm论坛51一品茶楼论坛,栖凤楼品茶全国楼凤app软件 ,栖凤阁全国论坛入口,广州百花丛bhc论坛杭州百花坊妃子阁

oe1(光电查) - 科学论文

过滤筛选

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） ▾

  • Evaluation of Low-Temperature Saturation Velocity in β -(Al?Ga???)?O?/Ga?O? Modulation-Doped Field-Effect Transistors

    摘要： We report on the high-field transport characteristics and saturation velocity in a modulation-doped β-(AlxGa1?x)2O3/Ga2O3 heterostructure. The formation of a 2-D electron gas (2DEG) in the modulation-doped structure was confirmed from the Hall measurements, and the 2DEG channel mobility increased from 143 cm2/V·s at room temperature to 1520 cm2/V·s at 50 K. The high electron mobility at 50 K made it feasible to achieve velocity saturation inside the channel. The saturation velocity was estimated based on both pulsed current–voltage measurements and small-signal radio frequency (RF) measurements. The measured velocity–field profile suggested a saturation velocity above 1.1 × 107 cm/s at 50 K. The small-signal RF characteristics were measured for the fabricated modulation-doped field-effect transistors with a Pt-based Schottky contact. The current gain cutoff frequency (ft) and maximum oscillation frequency (fmax) showed significant increases from 4.0/11.8 GHz at room temperature to 17.4/40.8 GHz at 50 K for the device with gate length of LG = 0.61 μm. The analysis of the low temperature ft based on device simulations indicated a peak velocity of 1.2 × 107 cm/s. The three-terminal off-state breakdown measurement further suggested an average breakdown field of 3.22 MV/cm. The high saturation velocity and high breakdown field in β-Ga2O3 make it a promising candidate for high-power and high-frequency device applications.

    关键词： mobility,β-Ga2O3,modulation-doped field-effect transistor (MODFET),2-D electron gas (2DEG),saturation velocity,high breakdown field

    更新于2025-09-23 15:22:29

  • First-principles study of the surface reparation of ultrathin InSe with Se-atom vacancies by thiol chemistry

    摘要： Utilizing first-principles calculations, the surface reparation of monolayer InSe with Se-atom vacancies by thiol chemistry was studied. The geometrical structures and electronic properties of monolayer InSe with Se-atom vacancies were evaluated before and after reparation by S atoms, benchmarked against defect-free case. The parameters of bond lengths, band gaps and carrier mobilities can be recovered to the standard of pristinely defect-free structure. Moreover, the interaction of S atom with complete part of monolayer InSe was also investigated. S atom cannot adsorb on the surface without Se-atom vacancies, while it can substitute Se atom or insert into the interior of monolayer InSe. And the insertion was able to induce a decrease by one order of magnitude. It was demonstrated that thiol chemistry was an effective method to repair Se-atom vacancies and maintain its oxidation resistance, while the insertion of S atom into the interior of monolayer InSe should be avoided.

    关键词： Indium selenides,Carrier mobility,Se-atom vacancies,Band gap,First-principles

    更新于2025-09-23 15:22:29

  • HMGB1 siRNA can reduce damage to retinal cells induced by high glucose in vitro and in vivo

    摘要： Background: Diabetic retinopathy (DR), one of the most common complications of late-phase diabetes, is associated with many risk factors, among which continuous low-grade inflammation is one of the principal ones. As such, lowering inflammation levels and maintain the viability of human retinal endothelial cells (HRECs) are critical for DR therapy. HMGB1 is a well-known proinflammatory cytokine. However, whether HMGB1 small interfering RNA (siRNA) can protect retina cells under a high-glucose environment from morphological changes and functional abnormalities remain undetermined. We aimed to investigate the effect of HMGB1 siRNA on retinal cells in DR. Materials and methods: A total of 80 adult Wistar rats were randomly divided into four groups (n=20 each): normal control, diabetes mellitus (DM), scrambled (Scr) siRNA, and HMGB1 siRNA. Rats in the DM, Scr siRNA, and siRNA groups were established by intraperitoneal injection of streptozotocin. At 16 weeks after injection, rats in the siRNA and Scr-siRNA groups were intravitreally injected with 2 μL HMGB1 siRNA and 2 μL Scr-siRNA, while rats in the control and DM groups were intravitreally injected with the same dose of sterile saline. At 1 week after injections, we performed the following experiments. Immunohistochemical staining and real-time quantitative polymerase chain reaction were performed to test HMGB1 protein and messenger RNA expression in retinas. We performed TUNEL assays to detect retinal cell apoptosis and electroretinography to detect retinal function. In HRECs treated with high glucose, proliferation, morphology, apoptosis, superoxide dismutase (SOD), and reactive oxygen species production were detected. Western blot was applied to determine the expressions of HMGB1 and its related protein and apoptosis protein. Results: Intravitreal injection of HMGB1 siRNA reduced protein and messenger RNA expression of HMGB1 (both P,0.05). Intravitreal injection of HMGB1 siRNA reduced apoptosis of retinal cells (P,0.05), protected morphological changes in the retina, and improved the function of the retina (P,0.05). In HRECs treated with high glucose, HMGB1 siRNA pretreatment increased cell viability, reduced cell apoptosis, and reduced oxidative damage to cells (all P,0.05). Western blot detection found that HMGB1 siRNA pretreatment can inhibit the expression of cleaved caspase 3 and improve the expression of BCL2 (P,0.05). HMGB1 and NFκB expression increased in a time-dependent manner in the high-glucose environment and IKKβ and NFκB protein expression decreased significantly after HMGB1 silencing. Conclusion: As a therapeutic target, HMGB1 siRNA can reduce retinal cell damage induced by high glucose in vitro and in vivo and delay DR progress through the HMGB1–IKKβ–NFκB signaling pathway.

    关键词： small interfering RNA,diabetic retinopathy,human retinal endothelial cells,inhibitor of nuclear factor κB,nuclear factor κB,high-mobility group box 1

    更新于2025-09-23 15:22:29

  • Improvement of electrical characteristics in regrown AlGaN/GaN MOSFETs by suppression of the residual interface charge

    摘要： In this paper, the influence of a regrown interface on the electrical properties of AlGaN/GaN heterostructure was investigated for recessed-gate MOSFETs fabricated by selective area regrowth. The electron mobility of the two-dimensional electron gas (2DEG) on regrown AlGaN/GaN structures was degraded when the 2DEG was near the regrown interface. The regrown interface had high carrier concentrations and Si impurities that caused degradation of the electron mobility of the 2DEG. Unintentional carrier generation at the regrown interface was eliminated by ultraviolet (UV) treatment before regrowth. A regrown AlGaN/GaN MOSFET device was then fabricated using the UV treatment. The device exhibited good performance such as normally-off operation without hysteresis or leaks. Improvement of the electrical characteristics of AlGaN/GaN MOSFETs was thus achieved by suppression of regrown interface charge.

    关键词： B2. Semiconducting gallium compounds,B3 High electron mobility transistors,A1. Interfaces,A3. Metalorganic vapor phase epitaxy,B1. Nitride

    更新于2025-09-23 15:22:29

  • InAs/GaSb thin layers directly grown on nominal (001)-Si substrate by MOVPE for the fabrication of InAs FINFET

    摘要： We demonstrated the fabrication of a densely packed InAs fins network for nanoelectronic applications. High crystalline quality GaSb/InAs layers have been grown directly on 300 mm nominal (001)-Si substrate. The InAs was then processed by etching step using a lithographic mask based on block copolymer to obtain sub-20nm width fins. This block copolymer has been optimized to self-assemble into lamellar structure with a period of 30nm, standing perpendicular to the substrate thanks to a neutral layer. STEM-HAADF characterization displays vertical sidewalls InAs fins with a width as low as 15nm spaced by almost 10nm. Early electrical characterizations exhibit a current flow through the connected fins.

    关键词： B3 High electron mobility transistors,B3 Field effect transistors,A3 Organometallic vapor phase epitaxy,A1 Etching,B2 Semiconducting III-V materials

    更新于2025-09-23 15:22:29

  • Investigation of Trap-Induced Threshold Voltage Instability in GaN-on-Si MISHEMTs

    摘要： It is shown that an EC–0.90 eV trap in commercial AlGaN/GaN MISHEMTs grown on a Si (111) substrate is responsible for a ?1.8-V threshold voltage (VT) instability using a combination of defect spectroscopy and double-pulsed current–voltage measurements. The EC ? 0.90 eV trap is located in the GaN buffer and is emptied by high drain biases in pinch-off, which raises the trap above the Fermi level in the GaN buffer. This trap also exhibits both fast and slow recovery processes that are explained by the availability of free electrons throughout the depth of the GaN buffer and the trapping process that depletes the free electron concentration. TCAD modeling is used to demonstrate this process and also to show why there is not a significant increase in buffer leakage current after the large negative VT shift due to this trap. This demonstrates that optimizing buffer designs are critical for ideal device performance.

    关键词： deep-level transient spectroscopy (DLTS),isothermal,GaN-on-Si,threshold voltage instability,metal-insulator-semiconductor high electron mobility transistors (MISHEMTs),Capture process,trap

    更新于2025-09-23 15:22:29

  • Temperature Dependent Electrical Transport Properties of High Carrier Mobility Reduced Graphene Oxide Thin Film Devices

    摘要： We confirm variable electrical transport properties of high mobility reduced graphene oxide (RGO) thin films fabricated by pulse laser deposition. The temperature dependent (5K–350K) four terminal electrical transport property measurements range hopping and thermally activated transport mechanism of the charge carriers at low (5K–210K) and high temperature (210K–350K) regions, respectively. The calculated localization length, the density of states near the Fermi level (EF), hopping energy, and Arrhenius energy gap provide useful information to explain the excellent electrical properties of the RGO films. Hall mobility measurement confirms p-type characteristics of the thin films. The charge carrier Hall mobility can be engineered by tuning the growth parameters, and the measured maximum mobility was 1596 cm2v-1s-1. The optimization of the improved electrical property is well supported by structural properties such as the defect density, average size of sp2 clusters and degree of reduction, which were investigated by Raman spectroscopy and X-ray diffraction analysis.

    关键词： PLD,variable range hopping,and Raman spectroscopy,hall mobility,Reduced graphene oxide,localization length

    更新于2025-09-23 15:22:29

  • Strain-Engineered Ultrahigh Mobility in Phosphorene for Terahertz Transistors

    摘要： Carrier mobility is a key parameter for the operation of electronic devices as it determines the ON state current and switching speed/frequency response of transistors. 2D phosphorene is considered as a potential candidate for field-effect transistors due to its high mobility. Here it is proposed to further enhance the carrier mobility of phosphorene and device performance via strain engineering. A systematic ab initio investigation on the anisotropic electronic structure of few-layer phosphorene reveals that the monolayer under 7.5–10% strain along zigzag direction shows an exceptional carrier mobility of ≈106 cm2 V?1 s?1, which is 10 times higher than the strain-free case. The simulated device performance shows that strain-engineered phosphorene–based field-effect transistors demonstrate a cut-off frequency of ≈1.14 THz with a gate length of 1.0 micron and 112 THz with a sub-10 nm gate length.

    关键词： carrier mobility,density functional theory,phosphorene,transistors,strain-engineered electronics

    更新于2025-09-23 15:22:29

  • Carbon nanotubes assisting interchain charge transport in semiconducting polymer thin films towards much improved charge carrier mobility; 碳纳米管辅助共轭聚合物薄膜链间载流子传输以提高迁移率;

    摘要： Conjugated polymers attracted much attention in the past few decades due to their wide applications in various optoelectronic devices and circuits. The charge transport process in conjugated polymers mainly occurs in the intrachain and interchain parts, where the interchain charge transport is generally slower than intrachain transport and may slow down the whole charge transport properties. Aiming at this issue, herein we employ semiconducting single-walled carbon nanotubes (s-SWNTs) as efficient charge-transporting jointing channels between conjugated polymer chains for improving the charge transport performance. Taking the typical conjugated polymer, ploy-N-alkyl-diketopyrrolo-pyrrole-dithienylthieno[3,2-b]thiophene (PDPP-TT) as an example, polymer thin film transistors (PTFTs) based on the optimized blended films of PDPP-TT/s-SWNTs exhibit an obviously increasing device performance compared with the devices based on pure PDPP-TT films, with the hole and electron mobility increased from 2.32 to 12.32 cm2 V?1 s?1 and from 2.02 to 5.77 cm2 V?1 s?1, respectively. This result suggests the importance of forming continuous conducting channels in conjugated polymer thin films, which can also be extended to other polymeric electronic and optoelectronic devices to promote their potential applications in large-area, low-cost and high performance polymeric electronic devices and circuits.

    关键词： connected conducting channel,conjugated polymer,s-SWNTs,carrier mobility

    更新于2025-09-23 15:22:29

  • Transport models in disordered organic semiconductors and their application to the simulation of thin-film transistors

    摘要： Relevant organic thin-film transistor (OTFT) simulation software must account for the main specificities of organic semiconductors (OSC) in term of free carriers’ density of states, transport mechanisms, and injection/collection properties from/to the device contacts. Among the parameters impacting the OTFT performance the carrier mobility is a key parameter. Usual methods to extract the mobility from current-voltage (I-V) measurements lead to obtained only an apparent, or effective, mobility. The value of the apparent mobility is different of the intrinsic channel organic semiconductor mobility. Despite this effective mobility actually determines most of a given device performance, therefore providing a very useful technology benchmark, it does not describe the intrinsic organic semiconductor material transport properties, and may even be misleading in the route to improve the OTFT fabrication process. To obtain a better understanding of the transport properties in OSCs using OTFT electrical characterization, implementing an appropriate physical mobility model in an OTFT I-V simulation software is a good way. The present paper gives a review of the carrier mobility models which can be implemented in OTFT simulation software. The review is restricted to the analytical and semi-analytical physical models taking into account the temperature, the carrier concentration and the electric field dependence of the carrier mobility in disordered OSCs.

    关键词： mobility,transport,modeling,organic semiconductors,Organic thin-film transistor (OTFT)

    更新于2025-09-23 15:22:29