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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 voltage-transient method for characterizing traps in GaN HEMTs

    摘要： Trapping e?ects in GaN HEMTs still limit their performance. The current-transient methodology has shown advantages in characterizing traps in the device. However, the voltage drift may cause errors in measurements with high accuracy requirements. In this paper, we present a methodology to characterize traps in GaN HEMTs using the voltage-transient measurements. We demonstrate the advantages of this method in terms of simplicity and e?ectiveness. In particular, it avoids the said problem due to the optimized measuring circuit. With this method, we have identi?ed the time constants and energy levels of traps in the AlGaN barrier layer and the GaN bu?er layer, respectively, in the devices. Their trapping and de-trapping mechanisms were also demonstrated at various temperature measurements. A classic exponential dependence of the degradation rate on the channel current was identi?ed.

    关键词： Trapping e?ect,GaN,Voltage transient,High electron mobility transistors (HEMTs)

    更新于2025-09-23 15:22:29

  • Towards fast and highly responsive SnSe <sub/>2</sub> based photodiode by exploiting the mobility of the counter semiconductor

    摘要： In photodetection, the response time is mainly controlled by the device architecture and electron/hole mobility, while the absorption coefficient and the effective separation of the electrons/holes are the key parameters for high responsivity. Here, we report an approach towards the fast and highly responsive infra-red photodetection using n-type SnSe2 thin film on p-Si (100) substrate keeping the overall performance of the device. The I-V characteristics of the device show a rectification ratio of ~147 at ± 5 V and enhanced optoelectronic properties under 1064 nm radiation. The responsivity is 0.12 A/W at 5 V and the response/recovery time constants were estimated as ~ 57±25/34±15 μs respectively. Overall, the response times are shown to be controlled by the mobility of the constituent semiconductors of a photodiode. Further, our findings suggest that n-SnSe2 can be intergrated with well established Si technology with enhanced opto-electronic properties and also pave the way in the design of fast response photodetectors for other wavelengths as well.

    关键词： Selenisation,DC sputtering,IR-Photodiode,SnSe2,Mobility

    更新于2025-09-23 15:22:29

  • Design and Mechanism of Embedding Specific Carbon Nanotubes in Sputtered Sandwiched InGaZnO Thin Film Transistors

    摘要： Amorphous indium gallium zinc oxide (a-IGZO) thin film transistors (TFTs) with high mobility are highly desirable to achieve high-speed operation in active-matrix displays and large-area sensors. Only a few works provided potential solutions. In this work, we have embedded carbon nanotubes (CNTs) into sputtered a-IGZO film to form a-IGZO/CNT/a-IGZO (ACA) sandwiched channel. In the ACA channel, the CNT percolation networks connected by the a-IGZO film work as high-speed carrier paths to enable faster transport of carriers during the on state while it does not degrade the leakage performance during the off state. The type and the embedding location of the CNT percolation network are critical to determine the ACA device performance, which is analyzed and verified by experiment and simulation. The optimum ACA design has approximately doubled the mobility and the on current density of the TFT. The design owns relatively better uniformity and provides a high-speed TFT solution for the advanced electronics.

    关键词： mobility,amorphous indium gallium zinc oxide,carbon nanotube,thin film transistor,sandwiched structure

    更新于2025-09-23 15:22:29

  • Effects of Trapped Charges in Gate Dielectric and High-k Encapsulation on Performance of MoS? Transistor

    摘要： The effects of trapped charges in gate dielectric and high-k encapsulation layer on the performance of MoS2 transistor are investigated by using SiO2 with different thicknesses as the gate dielectric and HfO2 as the encapsulation layer of the MoS2 surface. Results indicate that the positive trapped charges in SiO2 can increase the electrons in MoS2 for screening the scattering of charged impurity (CI) in SiO2 and at the SiO2/MoS2 interface to increase the carrier mobility. However, the CI scattering becomes stronger for thicker gate dielectric with more trapped charges and can dominate the electron screening effect to reduce the mobility. On the other hand, with the HfO2 encapsulation, the OFF-currents of the devices greatly increase and their threshold voltages shift negatively due to more electrons induced by more positive charges trapped in HfO2. Moreover, the screening effect of these electrons on the CI scattering results in a mobility increase, which increases with the magnitude of the CI scattering. A 51% improvement in mobility is obtained for the sample suffering from the strongest CI scattering, fully demonstrating the effective screening role of high-k dielectric on the CI scattering.

    关键词： Charged impurity (CI) scattering,mobility,high-k encapsulation,trapped charges,MoS2 FET

    更新于2025-09-23 15:22:29

  • Crystallisation Phenomena of In2O3:H Films

    摘要： The crystallisation of sputter-deposited, amorphous In2O3:H films was investigated. The influence of deposition and crystallisation parameters onto crystallinity and electron hall mobility was explored. Significant precipitation of metallic indium was discovered in the crystallised films by electron energy loss spectroscopy. Melting of metallic indium at ~160 °C was suggested to promote primary crystallisation of the amorphous In2O3:H films. The presence of hydroxyl was ascribed to be responsible for the recrystallization and grain growth accompanying the inter-grain In-O-In bounding. Metallic indium was suggested to provide an excess of free electrons in as-deposited In2O3 and In2O3:H films. According to the ultraviolet photoelectron spectroscopy, the work function of In2O3:H increased during crystallisation from 4 eV to 4.4 eV, which corresponds to the oxidation process. Furthermore, transparency simultaneously increased in the infrared spectral region. Water was queried to oxidise metallic indium in UHV at higher temperature as compared to oxygen in ambient air. Secondary ion mass-spectroscopy results revealed that the former process takes place mostly within the top ~50 nm. The optical band gap of In2O3:H increased by about 0.2 eV during annealing, indicating a doping effect. This was considered as a likely intra-grain phenomenon caused by both (In0)O?? and (OH?)O? point defects. The inconsistencies in understanding of In2O3:H crystallisation, which existed in the literature so far, were considered and explained by the multiplicity and disequilibrium of the processes running simultaneously.

    关键词： high mobility,In2O3:H,thin films,TCO,crystallisation

    更新于2025-09-23 15:22:29

  • Passive Optical Network Based Mobile Backhaul Enabling Ultra-Low Latency for Communications Among Base Stations

    摘要： Low latency is of key importance for mobile networks to support emerging time-critical applications, such as road traffic safety and efficiency. Meanwhile, a passive optical network (PON) is widely recognized as a promising solution for mobile backhaul networks thanks to its high capacity and low energy consumption. In the conventional PON-based mobile backhaul network, where base stations (BSs) are co-located with optical network units, the traffic between the neighboring BSs that are mainly caused by user mobility has to be first sent to the optical line terminal and even further, e.g., edge nodes of mobile core networks, resulting in high latency, although the adjacent BSs are geographically located close to each other. In this paper, a novel PON-based architecture is proposed for mobile backhaul to enhance the connectivity between neighboring BSs. Meanwhile, a tailored medium access control protocol and dynamic bandwidth allocation algorithm are introduced to support fast inter-BS communications. The results reveal that a low latency (less than 1 ms packet delay) for communications among any adjacent BSs can be achieved in the proposed PON-based mobile backhaul network, demonstrating great potential to support future time-critical applications.

    关键词： Low latency,Mobile backhaul,Passive optical network,User mobility,Inter-base station communications

    更新于2025-09-23 15:22:29

  • [IEEE 2018 Argentine Conference on Automatic Control (AADECA) - Buenos Aires, Argentina (2018.11.7-2018.11.9)] 2018 Argentine Conference on Automatic Control (AADECA) - Design and Calculation of a Solar Charge Station for Light Electric Vehicles

    摘要： This article presents the first advances of the Sustainable Electric Mobility project (MovES), within the framework of an institutional project of the National University of Rafaela (UNRaf), which consist of the calculation and design of a Off-Grid solar charging station that will supply a small fleet of light electric vehicles. There is also a brief review of the context of the EPACs and the existing regulations. The article concludes with the results obtained from the calculation that will be used for a future real implementation.

    关键词： E-Bike,Station,Charging Station,Solar Energy,Mobility

    更新于2025-09-23 15:22:29

  • Two-dimensional Kagome Lattices Made of Hetero Triangulenes are Dirac Semimetals or Single-Band Semiconductors

    摘要： Here we discuss, based on first-principles calculations, two-dimensional (2D) kagome lattices composed of polymerized hetero-triangulene units, planar molecules with D3h point group containing a B, C or N center atom and CH2, O or CO bridges. We explore the design principles for a functional lattice made of 2D polymers, which involves control of π-conjugation and electronic structure of the knots. The former is achieved by the chemical potential of the bridge groups, while the latter is controlled by the heteroatom. The resulting 2D kagome polymers have a characteristic electronic structure with a Dirac band sandwiched by two flat bands and are either Dirac semimetals (C center), or single-band semiconductors - materials with either exclusively electrons (B center) or holes (N center) as charge carriers of very high mobility, reaching values of up to ~8×103 cm2V-1s-1, which is comparable to crystalline silicon.

    关键词： high mobility,charge carriers,single-band semiconductors,hetero-triangulene units,Dirac semimetals,two-dimensional kagome lattices

    更新于2025-09-23 15:21:21

  • Gate Conduction Mechanisms and Lifetime Modeling of p-Gate AlGaN/GaN High-Electron-Mobility Transistors

    摘要： The gate conduction mechanisms in p-gallium nitride (GaN)/AlGaN/GaN enhancement mode transistors are investigated using temperature-dependent dc gate current measurements. In each of the different gate voltage regions, a physical model is proposed and compared to experiment. At negative gate bias, Poole–Frenkel emission (PFE) occurs within the passivation dielectric from gate to source. At positive gate bias, the p-GaN/AlGaN/GaN “p-i-n” diode is in forward operation mode, and the gate current is limited by hole supply at the Schottky contact. At low gate voltages, the current is governed by thermionic emission with Schottky barrier lowering in dislocation lines. Increasing the gate voltage and temperature results in thermally assisted tunneling (TAT) across the same barrier. An improved gate process reduces the gate current in the positive gate bias region and eliminates the onset of TAT. However, at high positive gate bias, a sharp increase in current is observed originating from PFE at the metal/p-GaN interface. Using the extracted conduction mechanisms for both devices, accurate lifetime models are constructed. The device fabricated with the novel gate process exhibits a maximum gate voltage of 7.2 V at t1% = 10 years.

    关键词： time-dependent breakdown (TDB),p-GaN gate,high-electron-mobility transistor (HEMT),enhancement mode,gallium nitride (GaN),Conduction mechanism

    更新于2025-09-23 15:21:21

  • [IEEE 2018 31st International Vacuum Nanoelectronics Conference (IVNC) - Kyoto, Japan (2018.7.9-2018.7.13)] 2018 31st International Vacuum Nanoelectronics Conference (IVNC) - MEMS ion source for ion mobility spectrometry

    摘要： This paper describes a miniature, silicon-glass, electron-impact ion source, in which a field emission cathode is separated from the external atmosphere by a vacuum semi-transparent Si3N4 membrane. High necessary for the proper operation of the ion source is generated on chip by an integrated micropump.

    关键词： electron-transparent membranes,micropump,field emission electron source,ion source,ion mobility spectrometry

    更新于2025-09-23 15:21:21