Thanks to unique physical and electrical properties (atomically thin, stretchable and strong with configurable electronic bandgap,...) there is great interest in the development of two-dimensional (2D) transition metal dichalcogenides (MX2) such as MoS2, WS2, MoSe2, and WSe2. These promising materials consist of van der Waals-bonded nanosheets much like graphene, and their properties depend greatly on the material quality and thickness (number of layers). At imec, a variety of routes is explored to reliably fabricate MX2 devices on a large scale, and this research requires fast and high-quality metrology to support and improve the processing, with Raman spectroscopy being one of the essential techniques. This non-destructive microscopy technique relies on the excitation and detection of vibrational energy modes at characteristic frequencies enabling immediate identification and assessment of the sample under study, as all MX2 materials have signature Raman spectra that are well documented. At the same time, the dimensions of these devices and the length scales related to the phenomena of interest are usually incompatible with the relatively large, diffraction-limited, probe area of micro-Raman spectroscopy. This challenge can be tackled by using Tip-Enhanced Raman Spectroscopy (TERS) which is a clever coupling between Raman and Scanning Probe Microscopy to translate the versatility of Raman spectroscopy into nanometer-sized spatial resolutions.
In this internship, we start off by familiarizing ourselves with the material and field of research, including hands-on training on imec's fully equipped TERS instrument. Next, the student will actively participate in the characterization of state-of-the-art MX2 devices, and the systematic interpretation of the resulting nano-Raman spectra. Eventually, crucial insight will be obtained into the parameters that determine ultimate device performance like local defects, charge carrier distributions, doping, material (in)homogeneity and many more.
Type of project: Thesis
Duration: 1 academic year
Required degree: Master of Engineering Technology, Master of Science, Master of Engineering Science, Master of Bioengineering
Required background: Physics, Nanoscience & Nanotechnology, Chemistry/Chemical Engineering, Electromechanical engineering, Materials Engineering, Mechanical Engineering
Supervising scientist(s): For further information or for application, please contact: Thomas Nuytten (Thomas.Nuytten@imec.be)