Open AccessElectron transport in discontinuous metal thin films
Author(s) -
James E. Morris
Publication year - 2022
Publication title -
nano express
Language(s) - English
Resource type - Journals
ISSN - 2632-959X
DOI - 10.1088/2632-959x/ac550c
Subject(s) - quantum tunnelling , thermal conduction , conduction electron , electron , materials science , metal , substrate (aquarium) , thin film , nanoparticle , nanotechnology , yield (engineering) , electron transport chain , condensed matter physics , chemical physics , optoelectronics , chemistry , composite material , physics , metallurgy , biochemistry , oceanography , quantum mechanics , geology
The structure and basic experimental electrical properties of vacuum evaporated discontinuous (island) metal thin films of discrete metal nanoparticles on insulating substrates are briefly reviewed. Then the widely accepted Neugebauer and Webb (N&W) electrostatically activated electron tunneling conduction model is covered (with enhancements) before the numerous discrepancies between this model and experimental observations are identified, e.g. minimal substrate bias effect, non-linear field distribution, anomalous AC effects, asymmetrical contact effects, and switching. A modified model, based on contact electron injection and extraction, and computer simulations are introduced which explain these discrepancies at a qualitative level. However, quantitative experimental verification of the model is not possible without stable, reproducible films of known structures. The paper concludes with a review of possible preparation techniques which could yield satisfactory samples, especially self-assembly of organically protected metal nanoparticles. One of these has already demonstrated electrostatically activated conduction.