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In this paper a performance based comparison of top and bottom contact organic thin film transistor (OTFT) device structures, using two dimensional numerical simulations has been carried out. In addition to this, investigations pe...
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In this paper a performance based comparison of top and bottom contact organic thin film transistor (OTFT) device structures, using two dimensional numerical simulations has been carried out. In addition to this, investigations pertaining to the estimation of contact resistance in these OTFTs were also performed. To estimate contact resistance the conventional transmission line method and modified transmission line method (M-TLM) were respectively invoked. Our simulation results clearly indicate that the latter is more accurate in the estimation of contact resistance compared to the conventional method. Furthermore, the M-TLM was used to estimate the gate voltage and film thickness dependence of the contact resistance for the two device structures. The observed results have been explained on the basis of the significantly lowered area of carrier injection and extraction regions, at the source/channel and channel/drain interface respectively, in bottom contact transistor that lead to its inferior performance over the top contact transistor.
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The transmission line method (TLM) is often used in characterizing the contact resistance of c-Si solar cells by cutting cells into strips parallel to the busbars. When applying this method to industrial solar cells, we found vari...
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The transmission line method (TLM) is often used in characterizing the contact resistance of c-Si solar cells by cutting cells into strips parallel to the busbars. When applying this method to industrial solar cells, we found various problems that have not been sufficiently explained in prior work. In this paper, we investigate different factors that influence the accuracy of this measurement, using both simulation and experimental methods. The following factors are shown to influence the extracted contact resistivity and are investigated in this work: (1) strip width; (2) edge shunting; (3) current flow through the intermediate unprobed fingers; (4) non-uniform contact resistance; and (5) non-uniform sheet resistance. In cases where the contact resistivity values determined from the TLM measurements and simulations were found to be inaccurate, we introduce correction procedures and measurement guidelines that reduce error. For example, when strip width is a factor, the measurement error of a 30 mm sample is reduced from 95.5% to 4.5% using a correction procedure validated by simulation. Furthermore, the methods are also shown to be very effective when applied to industrial solar cells. TLM measurements have an important role to play in both cell R&D and factory quality control, and this work can serve as a guide towards more accurate contact resistivity measurements. (C) 2017 Elsevier Ltd. All rights reserved.
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The characteristics of ruthenium (Ru) contact to boron doped diamond (BDD) have been investigated before and after annealing. The properties of as-deposited Ru contacts to BDD showed non-linear trend. Interestingly, the contact pr...
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The characteristics of ruthenium (Ru) contact to boron doped diamond (BDD) have been investigated before and after annealing. The properties of as-deposited Ru contacts to BDD showed non-linear trend. Interestingly, the contact properties of Ru/BDD exhibited ohmic contact behavior after post-annealing at 500 degrees C. The specific contact resistance (rho(c)) of Ru/BDD was 2.3 x 10(-4) Omega.cm(2) after annealing at 500 degrees C for 20 min in the argon (Ar) ambient. The contact barrier height was 0.075 eV +/- 0.14 eV after annealing at 500 degrees C, evaluated by X-ray photoelectron spectroscopy (XPS).
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To further improve the performance and power density of thermoelectric devices, the size of the device needs to be scaled down from macroscale to microscale. Different from the macroscale device, the specific contact resistivity r...
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To further improve the performance and power density of thermoelectric devices, the size of the device needs to be scaled down from macroscale to microscale. Different from the macroscale device, the specific contact resistivity rho (c) of the metal contact to the microscale device becomes a key point to the device's efficiency. In this study, a P type ZnSb thin film was deposited on glass substrate using a radio frequency magnetron sputtering system, followed by annealing at 325A degrees C in an Ar atmosphere. X-ray diffraction, scanning electron microscopy, and the Hall measurement system were utilized for characterization of the ZnSb. The ohmic contact properties of metallic Co and Mo on the annealed ZnSb thin films were investigated, indicating that metallic Co has a lower specific contact resistivity rho (c) to ZnSb. The effect of a diluted HCl-etch prior to Co electrode deposition was also studied. The results show that a HCl-etch is effective for the reduction of the rho (c). The dependence of rho (c) on the annealing temperature was also studied. Through HCl-etch and annealing at 200A degrees C, specific contact resistivity rho (c) as low as 10(-7) Omega cm(2) is successfully obtained on the Co electrode, providing a good method to fabricate a highly efficient ZnSb-based micro device.
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Graphene is the most promising contender for the future generation of electronic and photonic devices, based on its extraordinary properties. The effect of the metal interface with graphene, however, which completely alters its pr...
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Graphene is the most promising contender for the future generation of electronic and photonic devices, based on its extraordinary properties. The effect of the metal interface with graphene, however, which completely alters its properties, is of great importance. The effects of the substrate supporting the graphene matrix, the graphene/metal contact resistance and the overall metal oxide semiconductor capacitors (MOSCAP) for possible CMOS circuitry have been thoroughly investigated in this research work. We have fabricated a structure with pertinent deposition techniques and performed a detailed electrical analysis to obtain the transport characteristics. Nickel (Ni) is chosen as the transition metal which makes the chemisorption bonding with graphene while qualifying as an interface. We present an analysis of the metal contacts, a study of the metal resistivity at various planes, a study of the graphene (carbon) atom's resistance at the atomistic scale, the graphene based MOSCAP leakages, the necessary charge accumulation at the metal-graphene interface and the charge inversion just beneath the oxide layer.
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Abstract This paper details the fabrication and characterization of field-effect transistors (FETs) and photodetector devices based on few-layered palladium disulfide (PdS2) films. PdS2 is an emerging member of the transition meta...
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Abstract This paper details the fabrication and characterization of field-effect transistors (FETs) and photodetector devices based on few-layered palladium disulfide (PdS2) films. PdS2 is an emerging member of the transition metal dichalcogenide family that has not been extensively studied. In this study, we evaluated various characteristics of PdS2 by fabricating FET devices and measured the contact resistance using the transmission line method to be 114 MΩ ?documentclass[12pt]{minimal} usepackage{amsmath} usepackage{wasysym} usepackage{amsfonts} usepackage{amssymb} usepackage{amsbsy} usepackage{mathrsfs} usepackage{upgreek} setlength{oddsidemargin}{-69pt} begin{document}$$bullet$$end{document} μm. We evaluated the electron transport properties of the fabricated FETs to confirm their n-type behavior and measured their capacitance–voltage (C–V) curves. The field-effect mobility of the few-layered PdS2 FETs fabricated through transmission line patterning was investigated at room temperature (300?K) and found to be 2.85 cm2?V?1?s?1.
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W artykule omówiono metodę i wyniki pomiarów kontaktów omowych prowadzone za pomocą kołowych struktur c-TLM. Obliczono teoretyczne zależności oporu właściwego r_c od parametrów kontaktu i struktury pomiarowej a do weryf...
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W artykule omówiono metodę i wyniki pomiarów kontaktów omowych prowadzone za pomocą kołowych struktur c-TLM. Obliczono teoretyczne zależności oporu właściwego r_c od parametrów kontaktu i struktury pomiarowej a do weryfikacji wyników posłużono się kontaktami na bazie niklu do SiC. Struktury 4H-SiC miały postać warstw epitaksjalnych o grubości 3 μm i koncentracji nośników n =5.10~(16) + 10~(19) cm~(-3) wyhodowanych na wysoko-oporowych podłożach (0001) 4H-SiC. Metalizacje kontaktowe Ni i Ni/Si wytwarzane były metodą magnetronowego rozpylania katodowego z tar-getów Ni(4N) i Si(4N) w atmosferze argonu i poddawane obróbce termicznej metodą impulsową w przepływie argonu w temperaturze 900..1100℃. Przeanalizowano wyniki obliczeń r_c kontaktów n-SiC/Ni_2Si i n-SiC/Ni z zastosowaniem teorii c-TLM oraz jej form uproszczonych.
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