Sensor Applications of MoS2 and WS2 Thin Films
Thesis event information
Date and time of the thesis defence
Place of the thesis defence
L10, Linnanmaa campus
Topic of the dissertation
Sensor Applications of MoS2 and WS2 Thin Films
Doctoral candidate
Master of Science (Tech) Topias Järvinen
Faculty and unit
University of Oulu Graduate School, Faculty of Information Technology and Electrical Engineering, Microelectronics Research Unit
Subject of study
Electrical Engineering
Opponent
Associate Professor Raivo Jaaniso, University of Tartu
Custos
Professor Krisztian Kordas, University of Oulu
Sensor Applications of MoS2 and WS2 Thin Films
On-chip molybdenum and tungsten disulfide thin films: New enablers in sensing for Internet of Things applications
Molybdenum and tungsten disulfides (MoS2 and WS2) are layered, two-dimensional materials that have been utilized in micro- and nanoelectronics, telecommunications, energy storage and sensor applications due to their fascinating physicochemical properties.
In this doctoral research, these materials were synthesized directly on chips without the need of any transfer steps by first coating the surface with a thin metal film, from which vertically oriented, compact crystalline thin films of the corresponding sulfides were grown in sulfur vapor. The chemically active layer edges located on the surface of the film promote chemical and electrochemical sensing, whereas the oriented lattice of the layered material favors excellent photocarrier transport. In addition, the synthesis method is compatible with standard semiconductor processes enabling industrial production scale-up and simple interfacing with electronics circuits.
To demonstrate the usability of MoS2 and WS2 thin films, they were evaluated in different sensor applications. In gas sensing, they can detect ammonia (NH3) in minute concentrations. As light detectors, they are sensitive to light in the entire visible spectrum. For the third application, MoS2 thin films were studied as electrochemical sensors to detect dopamine using a wireless measuring device, interfaced with a smartphone. The study is expected to foster further research and development of multitudes of sensor devices with great potential for commercialization and extension of Internet of Things (IoT) applications.
Molybdenum and tungsten disulfides (MoS2 and WS2) are layered, two-dimensional materials that have been utilized in micro- and nanoelectronics, telecommunications, energy storage and sensor applications due to their fascinating physicochemical properties.
In this doctoral research, these materials were synthesized directly on chips without the need of any transfer steps by first coating the surface with a thin metal film, from which vertically oriented, compact crystalline thin films of the corresponding sulfides were grown in sulfur vapor. The chemically active layer edges located on the surface of the film promote chemical and electrochemical sensing, whereas the oriented lattice of the layered material favors excellent photocarrier transport. In addition, the synthesis method is compatible with standard semiconductor processes enabling industrial production scale-up and simple interfacing with electronics circuits.
To demonstrate the usability of MoS2 and WS2 thin films, they were evaluated in different sensor applications. In gas sensing, they can detect ammonia (NH3) in minute concentrations. As light detectors, they are sensitive to light in the entire visible spectrum. For the third application, MoS2 thin films were studied as electrochemical sensors to detect dopamine using a wireless measuring device, interfaced with a smartphone. The study is expected to foster further research and development of multitudes of sensor devices with great potential for commercialization and extension of Internet of Things (IoT) applications.
Last updated: 3.6.2024