December 2014Bachelorarbeit / Bachelor thesis

Lateral etching of graphene heterostructures

Fig.1: (a) Schematic representation of the fabrication process of hBN/graphene heterostructures. From top to bottom the assembly, the pattering and the contacting of such heterostructure are shown [1]. (b) hBN/graphene Hall bar devices as test structures for lateral etching by oxygen plasma. (c) Raman line cut of such device after O2 plasma treatment. Difference between two lines in x direction indicates the removal of graphene at the edges.

MotivationThe van der Waals assembly of two-dimensional materials created a new type of heterostructures and the encapsulation of graphene in hexagonal boron nitride (hBN) lead to well protected graphene on substrate with very high material quality. These heterostructures are contacted for electrical measurements from the side by metal touching the graphene inside the hBN. With removing the outer graphene atoms at the edge by lateral etching a new fabrication process for top and side gates can be found.

ProjectIn this research project we will develop, investigate and improve a fabrication process for lateral etching of graphene heterostructures based on oxygen plasma following previous experiments done in the group. The effect of lateral etching with different experimental settings and various parameters will be analyzed by Raman and scanning force microscopy (SFM) as well as room temperature electrical transport measurement. Finally, the developed process will be used for the fabrication of top and side gates on hBN/graphene heterostructures. This project covers tasks and activities in the fields of micro systems technology, analysis methods and basic transport measurements.

GoalThe goal of this project is to develop a process for lateral etching of graphene heterostructures and to

demonstrate its functionality on hBN/graphene heterostructures.

Proceeding Development of a fabrication process for lateral

etching of hBN/graphene heterostructures. Variation of process parameter and analysis

of the results by Raman and SFM. Implementation of the develop process for the

fabrication of top/side gates for hBN/graphene heterostructures.

Suited for students from the Physics and the Electrical Engineering departments.

ContactJan Dauber (jan.dauber@rwth-aachen.de) orProf. Christoph Stampfer (stampfer@physik.rwth-aachen.de)JARA-FIT and II. Institute of Physics A,RWTH Aachen University, 52074 Aachen, institut2a.physik.rwth-aachen.de

[1] Wang et. al., Science, Vol. 342 no. 6158 pp. 614-617 (2013)