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Gallium Nitride, in the form of epitaxial HEMT transistors on silicon carbide substrates is now almost universally acknowledged as the replacement for silicon bipolar, power MOSFET, high power devices in the RF, microwave, and mmW arenas. This is particularly true for GaN-on-SiC based MMIC's which enable state-of-the-art high frequency performance and bandwidth to be extended into Ku-Band and Ka-Band...
A metallic-target reactive co-sputtering technology is used to fabricate zinc tin oxide (ZTO) thin-film transistors (TFTs). The effect of the O2/(Ar+O2) flow rate ratio on the performance of the resulting TFTs is investigated in detail. It is found that an O2/(Ar+O2) ratio of 11%–12% produces devices with the best performance, including a linear mobility of 8.6 cm2/Vs, subthreshold swing of 0.36 V/decade,...
We propose a theoretical study on dual-frequency conformai antenna made by carbon nanotubes (CNTs) which is suitable to be printed on commercially available paper substrate. According to the simulation result, it is found that the radius of the conformal cylindrical surface and the conductivity of CNTs contribute little to the antenna performance. By further integrated onto the textile substrate,...
We present a study on multi-gate field-effect transistors that allow adjusting the potential landscape in semiconducting nanowires/tubes on the nanoscale. To this end, a damascenelike process is employed that allows fabricating a large number of gate structures that are contacted individually and exhibit lengths and inter-gate distances well below 10nm enabling to realize potential landscapes within...
In this work, a typical two-dimensional (2D) material WS2 on a dielectric substrate is measured by terahertz time-domain spectroscopy (THz-TDS) and analyzed using the Drude conductivity model. The transmittance and sheet conductivity of monolayer WS2 have been obtained. This technology can be used to measure the thin film 2D materials in THz frequency regions.
Complex surface conductivity at THz frequencies allowing the propagation of relatively slow plasmonic modes results from the unique electronic band structure of graphene, which is followed by a drastically reduced electrical size of the array unit cell and thereby reconfigurable performance. The reflectarray element based on silicon dioxide substrate and Boron Nitride substrate has been developed...
Temperature dependent substrate ramp measurements on AlGaN/GaN power high-electron-mobility transistors (HEMTs) are used to extract information on charge redistribution in the buffer structure as a function of substrate bias. The measurements are compared to a theoretical model, representing the ideal capacitive buffer stack. It is found that at room temperature some negative charge is stored in the...
Ohmic contacts to polycrystalline diamond thin films were formed using Au-Ti metal structure. The current-voltage characteristics of all contacts are linear and symmetric. Measured values of contact resistivity are less than 1 % of semiconductor resistivity. Essential variation of electrophysical parameters was not observed after rapid thermal annealing at 800 °C with 60 seconds duration. The thermionic...
Nanostructured pristine lead sulfide and copper iodide semiconductor films as well as copper doped lead sulfide and iodine-enriched copper iodide layers were obtained on solid and flexible substrates via Chemical Bath Deposition (CBD) and Successive Ionic Layer Adsorption and Reaction (SILAR) methods. Crystal structures, optical, electric and thermoelectric properties of the layers have been studied...
The knowledge of thermal properties of materials is important for many fields of technology such as thermal management for microelectronics, for the selection of interface or filler materials as well as for thermal simulations. We developed, designed and fabricated a characterization chip for the measurement of the thermal conductivity and diffusivity of, e.g., pastes, gels, fluids, polymers and bulk...
In this paper, Ti-doped GaZnO (GTZO) quaternary alloys were used as the transparent conductive oxides (TCOs) for Cu(In, Ga)SeSe2 (CIGS) solar cell application. These thin films are highly favorable for solar power systems. Photoluminescence measurement and X-ray diffraction were employed to investigate the GTZO thin films. Advantageous crystal quality was produced by radio-frequency magnetron sputtering...
In this work, a typical two-dimensional (2D) material MoS2 on a dielectric substrate is measured by terahertz time-domain spectroscopy (THz-TDS) and analyzed using the Drude model. The transmittance and sheet conductivity of monolayer MoS2 have been obtained. This technology can be used to measure the thin film 2D materials in THz frequency regions.
In this paper, a new packaging structure was proposed to reduce the heat accumulation of high-power UV-LEDs using silicone encapsulant with high thermal conductivity. The simulations for the thermal behavior of the traditional and proposed structures had been performed using finite element analysis (FEA). It was obtained that the improvement of temperature distribution was obviously enhanced as the...
Recently, we presented a multiscale model of field emission (FE) from carbon nanotube fibers (CBFs) taking into account Joule heating within the fiber and radiative cooling and the Nottingham effect at the tip of the individual carbon nanotubes in the array located at the fiber tip [1]. The model was used to predicts the fraction of carbon nanotubes (CNTs) being destroyed as a function of the applied...
This paper will discuss the fundamental study on nano-silver pastes newly developed with a unique approach using MO (Metallo-organic) technology. MO technology provides a low-temperature sintering capability. The nano-silver pastes show high electrical and thermal performance. However, degradation of die shear strength has been found by thermal cycling test due to the fragility of porous sintered...
We demonstrate electron transport characteristics of newly synthesized NiO nanoparticles on p-type Si substrate using scanning tunneling microscopy (STM). The resistivity and conductivity were determined to be 1.7×104 Ω.cm and 5.8×10−5 Ω.cm for Ni(OH)2 and 3.1×105 Ω.cm and 3.2×10−6 Ω.cm for NiO, respectively. Additionally, we also exemplify the characteristics features of graphene flakes with NiO...
Quasi-monocrystalline germanium (QMC Ge) is investigated for potential applications in high-efficiency, low-cost multi-junction solar cell design. The morphology and electrical resistivity of QMC Ge is characterized and computer simulations of MJSCs on Si substrates using QMC Ge interface layer are developed.
This paper presents the methodology for realisation of stretchable interconnects based on hybrid thin film stack of spray-coated conductive polymer PEDOT: PSS and evaporated gold (Au) film. The PEDOT: PSS film, with its properties in electrical conductivity and mechanical softness, serves as a stress release buffer in the layered hybrid structure. With the serpentine-shape design, the stretchable...
Graphene synthesis technology on substrates is promising, as is compatible with existing CMOS-technology. Knowledge about how to affect the substrate of choice for structural and electronic properties of graphene is important and opens up new opportunities in targeted influence on the properties of this unique material. Specialized measuring system was established to measure the galvanomagnetic characteristics...
The control of diamond nucleation and the early stages of diamond growth are essential for control of the diamond properties that are sensitive to or directly depend on the film anisotropy, grain size, and microscopic voids in the film. This phenomenon particularly affects the thermal conductivity of thin diamond films. Measuring the thermal conductivity/thermal diffusivity of material like diamond...
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