FABRICATION AND CHARACTERIZATION OF SUSPENDED GRAPHENE DEVICES
Physics, MSc. Thesis 2016
Assoc. Prof. Dr. İsmet İnönü Kaya (Thesis Advisor), Prof. Dr. Cihan Kemal Saçlıoğlu,
Asst. Prof. Dr. Cem Çelebi
Date & Time: 11th, July, 2016 – 10.00 AM
Place: FENS G032
Keywords : Suspended Graphene , Electrical Characterization, Low Temperature Physics
Graphene as a two-dimensional conducting material has attracted enormous attention due to its relativistic nature and interesting physical properties. Although theoretical studies on graphene are quite successful and revealing many interesting results about Dirac-like condensed matter systems, experimental realizations of these predictions are very challenging. Due to the naturally occurring electron-hole puddles and impurities acquired during the fabrication, graphene devices merely show their true potential, i.e. strongly correlated physics at the Dirac point. In order to achieve an ultra-high quality graphene device with less impurity concentration and higher carrier mobility, graphene sheets are whether suspended or placed on an atomically flat hBN layer, both of which reduce electron-hole puddles and lead ultra-high mobility graphene samples. This study introduces the techniques developed for fabricating ultra-clean, high mobility suspended monolayer graphene devices, which make Dirac point more accessible and produce high quality graphene samples. The fabrication and cleaning techniques (i.e. current annealing) leading devices with charge mobility values in excess of 106 cm2/V-s will be presented and the data revealing the improvement in graphene quality after current annealing will be discussed.