Contact resistance

About: Contact resistance is a research topic. Over the lifetime, 15262 publications have been published within this topic receiving 232144 citations. The topic is also known as: electrical contact resistance & ECR.

A review of micro-contact physics for microelectromechanical systems (MEMS) metal contact switches

Abstract: Innovations in relevant micro-contact areas are highlighted, these include, design, contact resistance modeling, contact materials, performance and reliability. For each area the basic theory and relevant innovations are explored. A brief comparison of actuation methods is provided to show why electrostatic actuation is most commonly used by radio frequency microelectromechanical systems designers. An examination of the important characteristics of the contact interface such as modeling and material choice is discussed. Micro-contact resistance models based on plastic, elastic-plastic and elastic deformations are reviewed. Much of the modeling for metal contact micro-switches centers around contact area and surface roughness. Surface roughness and its effect on contact area is stressed when considering micro-contact resistance modeling. Finite element models and various approaches for describing surface roughness are compared. Different contact materials to include gold, gold alloys, carbon nanotubes, composite gold-carbon nanotubes, ruthenium, ruthenium oxide, as well as tungsten have been shown to enhance contact performance and reliability with distinct trade offs for each. Finally, a review of physical and electrical failure modes witnessed by researchers are detailed and examined.

Effect of Ag Particle Size in Thick-Film Ag Paste on the Electrical and Physical Properties of Screen Printed Contacts and Silicon Solar Cells

Abstract: The impact of the Ag particle (metal powder in the screen printed paste) size on the quality of Ag thick-film ohmic contacts to high-sheet-resistance emitters of Si solar cells is investigated. Spherical particle size wasvaried in the range of 0.10-10 μm (ultrafine to large). Even though ultrathin glass regions are achieved for the large particle paste, giving low specific contact resistance (ρ c ), secondary ion mass spectroscopy measurements showed a higher Ag concentration (>10 1 5 cm - 3 ) at the p-n junction that increased the junction leakage current (J o 2 ) and decreased the V o c by ∼7 mV and fill factor (FF) by ∼0.02. Pastes with ultrafine Ag particles generally produced a thick glass layer at the Ag-Si contact interface, which increased ρ c and series resistance (R s ) (≥ 1 Ω cm 2 ), and lowered the FF by ∼0.03. Small to medium size Ag particles in the paste produced thin glass regions and many regularly distributed Ag crystallites at the contact interface. This resulted in low R s (< 1 Ω cm 2 ), high shunt resistance (60,558 Ω cm 2 ), low J o 2 (∼20 nA/cm 2 ), and high FF (0.781). Cell efficiencies of ∼17.4% were achieved on untextured float zone Si with 100 Ω/□ emitter by rapid firing of screen printed contacts in a lamp-heated belt furnace.

Well-aligned molybdenum oxide nanorods on metal substrates: solution-based synthesis and their electrochemical capacitor application

Abstract: In this work, we have successfully developed a mild solution-based route to elaborate well-aligned MoO3 and MoO2 nanorods as the electrode active materials directly on metallic current collectors for the first time. Prior to nanostructure growth, an incubation layer, containing peroxomolybdate precursors is deposited on the selected Cu foil, which has been found to play a crucial role on the oriented alignment of molybdenum oxide nanorods. The nanorod arrays are generated on the pre-treated Cu substrate by initial heterogeneous nucleation and subsequent growth from an aqueous or ethanol solution of a peroxomolybdate precursor. A good electrical transport and interaction with nanorod–Cu metal contacts are revealed by the current–voltage characteristics in this work. While such molybdenum oxide array films adhering to copper foil were employed directly as an integrative working electrode, the capacitive behaviors indicate that both molybdenum oxide array electrodes possess high specific capacitance and excellent cycle retention for electrochemical supercapacitor applications, which are investigated in detail by cyclic voltammetry and galvanostatic charge–discharge measurements at different current densities. Such enhancements are predominantly attributed to the direct lengthways electronic pathways, increased effective surface area and low contact resistance between the aligned nanorods and the Cu current collector junctions.

Effects of local Joule heating on the reduction of contact resistance between carbon nanotubes and metal electrodes

Abstract: We report here a practical application of known local Joule heating processes to reduce the contact resistance between carbon nanotubes and metallic electrical contacts. The results presented in this study were obtained from a series of systematic Joule heating experiments on 289 single-walled carbon nanotubes (SWCNTs) and 107 multiwalled carbon nanotubes (MWCNTs). Our experimental results demonstrate that the Joule heating process decreases the contact resistances of SWCNTs and MWCNTs to 70.4% and 77.9% of their initial resistances, respectively. The I-V characteristics of metallic nanotubes become more linear and eventually become independent of the gate voltages (Vgs). For semiconducting nanotubes, the contact resistance has a similar decreasing tendency but the dependency of source-drain current (Ids) on Vgs does not change with the Joule heating process. This suggests that the reduction of the contact resistance and the decrease of the transport potential barrier are largely attributed to the thermal...