A Resistivity Model For Ultrathin Films And Sensors

Keywords

Conductivity; gold thin films; modeling; palladium thin films; thin film hydrogen sensors; thin film modeling; thin film sensors; thin films; titanium thin films; ultra-thin films

Abstract

Gas sensors have been demonstrated based on the conductivity changes in ultrathin films. These sensors operate in a regime where three different physical phenomena determine the total resistivity of the film; quantum mechanical coupling between metallic islands, bulk material conductivity of the islands, and network resistivity. We present a lumped parameter model that simulates thin-film growth and calculates the total film resistance during the growth process accounting for these three phenomena. The model contains four free parameters and yields a good agreement with experimental data presented for palladium, titanium, and gold. The primary benefit of this model is that it shows the relative contribution of each source of conductivity during the growth process providing insight into the operation of ultrathin films as gas sensors. We then model an ultrathin-film palladium-based hydrogen sensor and show that the sensing mechanism is primarily due to variations in quantum tunneling.

Publication Date

4-1-2015

Publication Title

IEEE Sensors Journal

Volume

15

Issue

4

Number of Pages

2412-2418

Document Type

Article

Personal Identifier

scopus

DOI Link

https://doi.org/10.1109/JSEN.2014.2379012

Socpus ID

84923233312 (Scopus)

Source API URL

https://api.elsevier.com/content/abstract/scopus_id/84923233312

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