Electrochemiluminescence by tunnel emission of hot electrons into aqueous solution is a sensitive method for detection of luminophores e.g. rare-earth chelates, which may be used as labels in bioassays. Electrons are injected into solution from an insulating film-coated working electrode, working against a platinum counter electrode. Conductive silicon electrodes with various tunnel dielectric materials e.g. thermal oxide have been used in previous work. In this paper we explore the use of metal thin film electrodes on silicon and glass substrates, using tunneling dielectrics of aluminum oxide and silicon dioxide made by the low-temperature processes of atomic layer deposition or plasma-enhanced chemical vapor deposition. (C) 2010 Elsevier B.V. All rights reserved.