Experimental Semiconductor Physics

Course with Participations of Group Members

Offers for Theses in the Group

Improving Contacts to Two-Dimensional (2D) Materials with Ultrathin Interfacial Oxides and Nitrides

Two-dimensional (2D) van der Waals (vdW) materials are promising for future nanoelectronic devices. However, their performance is hampered by the presence of a large number of defects at the metal/2D material interfaces. This Master’s thesis project will extend the applications of atomic layer deposition (ALD) to engineer functional electrical contacts in 2D nanoelectronic devices using interfacial transition metal oxides and nitrides of controlled stoichiometry and electronic properties. ALD-grown films will be explored as interfacial layers that are presumably vdW-bonded to the 2D material (e.g., MoS2) on one side and chemically bonded to the metal electrode one the other side. ALD allows for precise control of the material composition in order to tune electronic properties, such as work function, dielectric constant, and defect concentrations. The electronic properties of ultrathin ALD layers of different compositions and their complex interactions with 2D materials, which in turn affect transport, will be investigated in a combined effort using 2D field-effect transistor (FET) transport measurements, spectroscopic methods, and scanning probe microscopy techniques. This contacting scheme will be exploited to achieve both p- and n-type conductance, which is key for logic applications and difficult to achieve with 2D materials. Techniques you will be trained on: • Plasma-enhanced atomic layer deposition (PE-ALD) • Spectroscopic Ellipsometry (SE) • Atomic force microscopy (AFM) and Kelvin probe force microscopy (KPFM) • Nanoelectronics device fabrication with optical and electron beam lithography • Current-voltage (I-V) measurements in the dark and under illumination at variable temperatures • Optical characterization by Raman and photoluminescence spectroscopy Conditions and requirements: • Possible start date: From September 2019 • Duration: one year, full-time • Focus on condensed matter physics, applied engineering physics or related fields • Basic knowledge of semiconductor physics • Completion of all exams necessary for master’s degree For further information, please contact Alex Henning (alex.henning@wsi.tum.de, Tel.: 089/289 11491). To apply, please submit your CV and transcript of records.

suitable as

• Master’s Thesis Condensed Matter Physics
• Master’s Thesis Applied and Engineering Physics

Supervisor: Ian Sharp

Current and Finished Theses in the Group