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Simultaneous Monitoring and Evaluation of Current and Mass Transients with the QCMB in the Millisecond Range
Author(s) -
Geißler D.,
Hartig P.,
Wünsche M.,
Meyer H.,
Schumacher R.
Publication year - 1999
Publication title -
electroanalysis
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.574
H-Index - 128
eISSN - 1521-4109
pISSN - 1040-0397
DOI - 10.1002/(sici)1521-4109(199905)11:6<412::aid-elan412>3.0.co;2-z
Subject(s) - millisecond , monolayer , resonator , chemistry , analytical chemistry (journal) , electrode , resolution (logic) , materials science , optoelectronics , physics , biochemistry , chromatography , astronomy , artificial intelligence , computer science
An experimental set‐up is described which allows the simultaneous recording of current and mass transients with millisecond resolution by using 5 MHz quartz resonators operated in a liquid environment. At the same time a mass resolution of a few nanograms is realized. It is demonstrated that this set‐up allows the application of fast potential pulses to electrochemically deposit/strip copper adlayers. The results proved that the obtained frequency response of the QCMB of 1 ms due to a sudden mass change has to be regarded as an upper limit and is independent on the type of oscillator circuit used. Thus, this technique allows monitoring and evaluation of fast electrode processes such as copper deposition/stripping by comparing current and mass transients recorded simultaneously. With this technique the integral sensitivity E i for quartz resonators contacted with one face to a liquid was reinvestigated on the basis of charge and frequency changes associated with absolute mass changes spanning from the monolayer regime up to more than one hundred atomic layers. An unexpected sensitivity drop is observed in the lower monolayer regime which is related to interfacial processes that occur due to shear elongations at the phase boundary solid/liquid.