Doctoral dissertation: Hot electrons and atomic layer deposition –miniature chemical analysis
09.01.2012
M.Sc. Antti J. Niskanen’s doctoral dissertation examines two microfabricated chemical sensors. Hot electron induced electrochemiluminescence (HECL) sensors can be used to attain extremely high sensitivities in bio and immunoanalysis, such as in the analysis of TSH hormone levels that regulate the hormonal output of the thyroid gland. Like regular electrochemiluminescence (ECL), HECL is also based on the electrochemical emission of light, but it has certain benefits over the regular ECL, such as better sensitivity with a broader range of analytes and the possibility to measure several analytes at a time while using relatively simple equipment and methods.
HECL is a relatively new analysis method and Niskanen’s doctoral dissertation examines how suitable various materials and production methods are for the electrodes that are used to produce hot electrons in the solution being examined. Niskanen also developed an integrated, single-use sensor component that facilitates and accelerates the analysis.
Microfabricated gas sensors are commonly used to detect toxic gases near processes or equipment that require the use of such gases, in the environment and at accident scenes. Niskanen’s doctoral dissertation examines the use of atomic layer deposited (ALD) thin films in microfabricated gas sensors. ALD enables the deposition of various thin film materials and material combinations, but requires certain changes to the fabrication process of the sensors. Based on the components produced using the new process, the ALD films were found suitable for this purpose. The new process can be a less expensive way of fabricating gas sensors since a larger number of the production phases are performed on silicon wafers instead of on individual components.
Chemical sensors are needed in analysis laboratories and production facilities, but also in health care, environmental protection and the monitoring of personal safety. In many of these applications the small size of the analysing device, a small amount of sample required, and an inexpensive price are desirable properties.This is why the microfabrication methods developed for the needs of microelectronics are also used in the production of chemical sensors.
M.Sc. Antti J.Niskanen’s doctoral dissertation ”Thin film technology for chemical sensors” will be publicly examined at 12 noon on 27 January 2012 at the Aalto University School of Electrical Engineering in the Micronova large lecture hall (Tietotie 3, Espoo).
More information about dissertation
More information:
Antti J. Niskanen
tel. 050 309 9114,
Antti.Niskanen [at] iki [dot] fi