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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） ▾

  • Synergistic enhancement in the microelectronic properties of poly-(dioctylfluorene) based Schottky devices by CdSe quantum dots

    摘要： This paper reports the potential application of cadmium selenide (CdSe) quantum dots (QDs) in improving the microelectronic characteristics of Schottky barrier diode (SBD) prepared from a semiconducting material poly-(9,9-dioctylfluorene) (F8). Two SBDs, Ag/F8/P3HT/ITO and Ag/F8-CdSe QDs/P3HT/ITO, are fabricated by spin coating a 10 wt% solution of F8 in chloroform and 10:1 wt% solution of F8:CdSe QDs, respectively, on a pre-deposited poly(3-hexylthiophene) (P3HT) on indium tin oxide (ITO) substrate. To study the electronic properties of the fabricated devices, current-voltage (I–V) measurements are carried out at 25 °C in dark conditions. The I–V curves of Ag/F8/P3HT/ITO and Ag/F8-CdSe QDs/P3HT/ITO SBDs demonstrate asymmetrical behavior with forward bias current rectification ratio (RR) of 7.42 ± 0.02 and 142 ± 0.02, respectively, at ± 3.5 V which confirm the formation of depletion region. Other key parameters which govern microelectronic properties of the fabricated devices such as charge carrier mobility (μ), barrier height (φb), series resistance (Rs) and quality factor (n) are extracted from their corresponding I–V characteristics. Norde’s and Cheung functions are also applied to characterize the devices to study consistency in various parameters. Significant improvement is found in the values of Rs, n, and RR by 3, 1.7, and 19 times, respectively, for Ag/F8-CdSe QDs/P3HT/ITO SBD as compared to Ag/F8/P3HT/ITO. This enhancement is due to the incorporation of CdSe QDs having 3-dimensional quantum confinement and large surface-to-volume area. Poole-Frenkle and Richardson-Schottky conduction mechanisms are also discussed for both of the devices. Morphology, optical bandgap (1.88 ± 0.5 eV) and photoluminescence (PL) spectrum of CdSe QDs with a peak intensity at 556 nm are also reported and discussed.

    关键词： poly-(9,9-dioctylfluorene),charge carrier mobility,Schottky barrier diode,microelectronic properties,CdSe quantum dots

    更新于2025-09-23 15:19:57

  • [IEEE 2019 IEEE International Conference on Mechatronics and Automation (ICMA) - Tianjin, China (2019.8.4-2019.8.7)] 2019 IEEE International Conference on Mechatronics and Automation (ICMA) - Optimization of Spectroscope Parameters for Single-beam Pulsed Laser Scanning Circumferential Detection System

    摘要： In this paper, we have extensively investigated the impact of anode recess on the reverse leakage current, forward voltage (VF), and dynamic characteristics of Au-free AlGaN/GaN Schottky barrier diodes with a gated edge termination (GET-SBDs) on 200-mm silicon substrates. By increasing the number of atomic layer etching (ALE) cycles for anode recessing, we have found that: 1) the reverse leakage current is strongly suppressed due to a better electrostatic control for pinching off the channel in the GET region; a median leakage current of ～1 nA/mm and an ION/IOFF ratio higher than 108 have been achieved in GET-SBDs with six ALE cycles; 2) the forward voltage (～1.3 V) is almost independent of the ALE cycles, taking into account its statistical distribution across the wafers; 3) when the remaining AlGaN barrier starts to be very thin (in the case of six ALE cycles), a spread of the ON-resistance, mainly attributed to the GET region, can occur due to the difficult control of the remaining AlGaN thickness and surface quality; and 4) the dynamic forward voltage of GET-SBDs shows a mild dependence on the ALE process in pulsed I–V characterization, and a more ALE-dependent dynamic ON-resistance is observed.

    关键词： leakage,diode,AlGaN/GaN,GET-SBD,metal–insulator–semiconductor high-electron mobility transistor (MISHEMT),200-mm,atomic layer etching (ALE)

    更新于2025-09-23 15:19:57

  • The origin of distorted intensity pattern sensed by a lens and antenna coupled AlGaN/GaN-HEMT terahertz detectors

    摘要： Here, we report artefacts in the intensity pattern of a focused terahertz beam around 1 THz by scanning photocurrents as a function of the beam location and the frequency. Although the exact distortion is found with our specific antenna design, we believe similar artefacts could be commonplace in antenna-coupled FET terahertz detectors when the beam spot becomes comparable with the antenna size. To eliminate such artefact, new antenna designs are welcomed to achieve strong asymmetry in the terahertz field distribution under the gate while maintaining a more symmetric radiation pattern for the whole antenna.

    关键词： high electron mobility transistor,terahertz detector,self-mixing,local electrical field

    更新于2025-09-23 15:19:57

  • Simple Route to Interconnected, Hierarchically Structured, Porous Zn2SnO4 Nanospheres as Electron Transport Layer for Efficient Perovskite Solar Cells

    摘要： Constructing electron transport layer (ETL) with higher carrier mobility and suitable bandgap is of key importance as it greatly influences the photovoltaic performance of perovskite solar cells (PSCs). Zn2SnO4 (ZTO) carries a high electron mobility of 10–30 cm2 V-1 s-1, an order of magnitude over the widely used TiO2 ETL in perovskite solar cells (PSCs), rendering it an excellent alternative to TiO2 ETL. Herein, we report a simple yet robust polymer-templating route to interconnected, hierarchically structured, porous ZTO nanospheres as an efficient ETL for high-performance organolead halide PSCs. The porous ZTO nanospheres ETL, composed of an assembly of 4.5-nm ZTO nanoparticles on the surface of porous nanosphere possessing 80-100 nm cavity, renders markedly improved light absorption, enhanced electron extraction, facilitated charger transportation, and suppressed carrier recombination in the resulting PSCs, which exhibit a power conversion efficiency (PCE) of 17.14%, greatly outperforming the device based on the ZTO nanoparticles (14.02%; i.e., without porosity). As such, the strategy for crafting porous yet hierarchically structured semiconductors with high carrier mobility may open up an avenue to create robust ETL, and by extension, hole transport layer (HTL) for high-performance optoelectronics.

    关键词： Zn2SnO4,perovskite solar cells,high electron mobility,hierarchical nanostructure,Electron transport layer

    更新于2025-09-23 15:19:57

  • High-responsivity turbostratic stacked graphene photodetectors using enhanced photogating

    摘要： High-responsivity graphene photodetectors were fabricated using turbostratic stacked graphene, which provided enhanced photogating. Photogating is a promising means of increasing the responsivity of graphene photodetectors, and this effect is proportional to carrier mobility. Turbostratic stacked graphene exhibits higher carrier mobility than conventional monolayer graphene because it has the same band structure as monolayer graphene while preventing scattering by the underlying SiO2 layer. The photoresponse of these devices at a wavelength of 642 nm was approximately twice that obtained for a conventional monolayer graphene photodetector. The results reported show the feasibility of producing high-responsivity graphene-based photodetectors using a simple fabrication technique.

    关键词： turbostratic stacked graphene,photogating,photodetectors,graphene,carrier mobility

    更新于2025-09-23 15:19:57

  • Photoelectric properties of SnO2: Ag/Pa??Si heterojunction photodetector

    摘要： N-type Tin dioxide thin films with thickness (350 nm) prepared by thermal evaporation method. The thin film SnO2 was doped with Ag by the rate (0.01, 0.02 and 0.03). Atomic Force Microscopic (AFM) was adopted to determine the grain size and roughness of the film surface. The electrical properties were determined by mean of Hall Measurement system and mobility was calculated. SnO2: Ag/P–Si photodetectors demonstration the highest described visible responsivity of (0.287 A/W) with the Ag ratio of (0.03). I–V characteristics with different power density were measured. The best sensitive value of the spectral response, specific detectivity and quantum efficiency at wavelength (422 nm).

    关键词： Ag/P–Si,Quantum efficiency,Detector,SnO2,Mobility

    更新于2025-09-23 15:19:57

  • Noise characteristics of Ni/GaN Schottky barrier IMPATT diode based on polar- and nonpolar-oriented wurtzite GaN for terahertz application

    摘要： This paper reports a study investigating the noise performance of Ni/GaN Schottky barrier impact-ionization-avalanche-transit-time (IMPATT) diodes based on the polar- and nonpolar-oriented wurtzite GaN by a numerical simulation. Results show that the nonpolar IMPATT diode exhibits a significant wider and higher frequency-band corresponding to the low noise measure (NM). The upper limit of the low-noise frequency-band of the IMPATT diode shifts from 159.2 GHz to 184.3 GHz, from 183.4 GHz to 245.7 GHz and from 212.2 GHz to 285.6 GHz when J0 ? 1 kA/cm2, 10 kA/cm2 and 100 kA/cm2, respectively, comparing the polar with the nonpolar IMPATT diodes. Our analysis proves that the mechanism comes from excellent properties of the Negative Differential Mobility (NDM) characteristic in the nonpolar orientation wurtzite GaN. In particular, the nonpolar diode still demonstrates better unity between the noise and RF power performances and can significantly improve the stability of IMPATT diodes at terahertz frequency.

    关键词： Negative differential mobility,Ni/GaN,Polarization,Noise measure,Negative resistance

    更新于2025-09-23 15:19:57

  • Nanoscale Interfaces of Janus Monolayers of Transition Metal Dichalcogenides for 2D Photovoltaic and Piezoelectric Applications

    摘要： Using first-principles calculations, we demonstrate a combination of two emergent fields, type-II van der Waal heterostructures and Janus structures, for the purpose of optimizing the harvesting of solar and nanoelectromechanical energy. The most stable stacking order in these nanoscale heterobilayers comprising of Janus monolayers of transition metal dichalcogenides has been ascertained based on the interlayer binding energies. The binding energies in WSeTe/WSTe and MoSeTe/WSTe heterobilayers are found to be -27.93 and -25.67 meV/?2 at an equilibrium interlayer layer distance of 3.25 ? and 3.32 ? respectively, indicating the exothermicity in the process of heterobilayer formation and hence, its experimental feasibility. The mechanical and dynamical stabilities have also been confirmed for these heterobilayers using the Born Huang stability criteria and phonon dispersion calculations. Our results unveil the mechanism underlying the electronic, piezoelectric, photocatalytic properties and carrier mobility in these Janus heterobilayers. Power conversion efficiency in the 2D ultrathin excitonic solar cells constituted by some of the heterobilayers studied in this work, has been found to lie in the range of 15-20%. Moreover, a very high carrier mobility (>200 cm2/V.s) together with a large visible light absorption coefficient (α ~ 105 cm-1) has been observed in these hetero-bilayers. The piezoelectric coefficients in these ultrathin heterobilayers (d33 = 13.91 pm/V) is found to reach close to the values obtained in multilayer/bulk structures built from Janus monolayers of Mo-based dichalcogenides. Our findings highlight the promising applications of these heterobilayers in ultrathin excitonic solar cells, nanoelectronics and nanopiezotronics.

    关键词： van der Waals heterostructures,transition metal dichalcogenides,photovoltaic applications,Janus monolayers,piezoelectricity,carrier mobility

    更新于2025-09-23 15:19:57

  • With PBDB-T as the Donor, the PCE of Non-Fullerene Organic Solar Cells Based on Small Molecule INTIC Increased by 52.4%

    摘要： At present, most high-performance non-fullerene materials are centered on fused rings. With the increase in the number of fused rings, production costs and production difficulties increase. Compared with other non-fullerenes, small molecule INTIC has the advantages of easy synthesis and strong and wide infrared absorption. According to our previous report, the maximum power conversion efficiency (PCE) of an organic solar cell using PTB7-Th:INTIC as the active layer was 7.27%. In this work, other polymers, PTB7, PBDB-T and PBDB-T-2F, as the donor materials, with INTIC as the acceptor, are selected to fabricate cells with the same structure to optimize their photovoltaic performance. The experimental results show that the optimal PCE of PBDB-T:INTIC based organic solar cells is 11.08%, which, thanks to the open voltage (VOC) increases from 0.80 V to 0.84 V, the short circuit current (JSC) increases from 15.32 mA/cm2 to 19.42 mA/cm2 and the fill factor (FF) increases from 60.08% to 67.89%, then a 52.4% improvement in PCE is the result, compared with the devices based on PTB7-Th:INTIC. This is because the PBDB-T:INTIC system has better carrier dissociation and extraction, carrier transportation and higher carrier mobility.

    关键词： polymer solar cells (PSCs),synthesize easily,carrier transportation and extraction,carrier mobility,strong and wide infrared absorption,non-fullerene small molecule acceptor

    更新于2025-09-23 15:19:57

  • [IEEE 2019 3rd International Symposium on Multidisciplinary Studies and Innovative Technologies (ISMSIT) - Ankara, Turkey (2019.10.11-2019.10.13)] 2019 3rd International Symposium on Multidisciplinary Studies and Innovative Technologies (ISMSIT) - Concentrated Photovoltaic Solar Power Investigation in Space Application

    摘要： In this paper, we consider a network in which lower power nodes (LPNs) are deployed jointly within macrocells. However, there are significant differences between the transmit power levels, coverage areas, and deployment densities of these two types of base stations. Such disparities lead to an unfair load distribution, as well as a lower throughput for picocells’users equipments (UEs). A good solution to such issues is the exploitation of the cell range expansion (CRE) technique. Although CRE has widely proven its effectiveness, it may degrade the network capacity if the cell bias is not chosen properly. In fact, it may generate severe intercell interference at extended region cell (ERC) UEs, which leads to a deterioration of their throughput. We thus propose a downlink coordinated cell range expansion for mobility management (CCREMM) strategy that analytically computes the joint optimal bias at picocells and macrocells. CCREMM mitigates the interference at ERC-UEs by accounting for their maximum tolerable interference. Moreover, CCREMM reaches the load balancing and the UE QoS satisfaction by accounting for additional parameters. It will be proven that our strategy which is associated with the maximum throughput scheduling technique, results in a cell load-balancing improvement, fairness, and a 50–90% UE throughput enhancement. These performance figures are shown to surpass those achieved by alternative approaches proposed in the existing literature.

    关键词： HetNets,load balancing,QoS,resource allocation,mobility management

    更新于2025-09-23 15:19:57