Abstract

Energy has been a key factor for human development throughout history. On the other hand, increasing energy demand and adverse effects of traditional energy sources on the environment motivate the drive for novel ways to minimize energy losses in mechanical systems. Within this context, layered materials are of interest due to their solid lubrication properties, which are of critical importance for a number of specialized application areas. Complementarily, the rise of two-dimensional materials led to renewed interest in the electrical properties of layered materials, from which two-dimensional samples are derived.

Motivated as above, this thesis presents a combined study of frictional and electrical properties of prototypical layered materials (highly oriented pyrolytic graphite (HOPG) and molybdenum disulfide (MoS2)) on the nanoscale, through atomic force microscopy (AFM). Specifically, we present complementary maps of friction and conductivity on MoS2, where atomic-scale stick-slip features are present. In addition, we show that HOPG exhibits a diverse electrical landscape, whereby different terraces show different levels of conductivity, with some regions additionally showing a strong dependence on scanning direction. A hypothesis based on tip asymmetry and the puckering effect potentially explains the findings. Overall, this work highlights the non-triviality of the electrical and frictional properties of layered materials on the nanoscale, as well as their interplay.
 

Biography

Kutay Ozyurt is currently a Master’s student in MBSE at UC Merced. He joined Baykara Lab in Fall 2022, shortly after earning his B.S. in Physics from the Izmir Institute of Technology. In Baykara Lab, he focuses on studying the fundamental aspects of nanoscale friction and conductivity on layered materials through AFM experiments.