title: Electron transport in gold colloidal nanoparticle-based strain gauges.
abstract: A systematic approach for understanding the electron transport mechanisms in resistive strain gauges based on assemblies of gold colloidal nanoparticles (NPs) protected by organic ligands is described. The strain gauges were fabricated from parallel micrometer wide wires made of 14 nm gold (Au) colloidal NPs on polyethylene terephthalate substrates, elaborated by convective self-assembly. Electron transport in such devices occurs by inter-particle electron tunneling through the tunnel barrier imposed by the organic ligands protecting the NPs. This tunnel barrier was varied by changing the nature of organic ligands coating the nanoparticles: citrate (CIT), phosphines (BSPP, TDSP) and thiols (MPA, MUDA). Electro-mechanical tests indicate that only the gold NPs protected by phosphine and thiol ligands yield high gauge sensitivity. Temperature-dependent resistance measurements are explained using the 'regular island array model' that extracts transport parameters, i.e., the tunneling decay constant β and the Coulomb charging energy E(C). This reveals that the Au@CIT nanoparticle assemblies exhibit a behavior characteristic of a strong-coupling regime, whereas those of Au@BSPP, Au@TDSP, Au@MPA and Au@MUDA nanoparticles manifest a weak-coupling regime. A comparison of the parameters extracted from the two methods indicates that the most sensitive gauges in the weak-coupling regime feature the highest β. Moreover, the E(C) values of these 14 nm NPs cannot be neglected in determining the β values.
authors: Université de Toulouse, LPCNO, INSA-CNRS-UPS, 135 avenue de Rangueil, Toulouse, 31077, France.
authors: Helena
authors: H
authors: Moreira
authors: Jérémie
authors: J
authors: Grisolia
authors: Neralagatta M
authors: NM
authors: Sangeetha
authors: Nicolas
authors: N
authors: Decorde
authors: Cosmin
authors: C
authors: Farcau
authors: Benoit
authors: B
authors: Viallet
authors: Ke
authors: K
authors: Chen
authors: Guillaume
authors: G
authors: Viau
authors: Laurence
authors: L
authors: Ressier