M.Sc Thesis


M.Sc StudentLevy Eden
SubjectElectrical and Mechanical Coupling between
Low Dimensions Materials
DepartmentDepartment of Nanoscience and Nanotechnology
Supervisor DR. Yuval Yaish


Abstract

Low dimensional materials have attracted vast attention in the past decades due to their exceptional physical and electrical properties. These materials have the potential to function as the building blocks for future electronic devices and technological applications.

In recent years, researchers have investigated the dependence of rotational alignment of two-dimensional (2D) layers on the electronic and mechanical properties of the layer. They have discovered a tremendous change in the electronic coupling between the layers as a function of the rotation angle. This finding has significantly improved the performance of electronic devices.

Although the orientation between two-dimensional (2D) layers has been widely studied, the rotational alignment between one- and two-dimensional materials barely attracts attention.

In this work, we fabricate an innovative heterostructure combining carbon nanotubes, graphene and hexagonal boron nitride (hBN) layers in order to study the influence of the rotation on the electrical properties of the carbon nanotube.

We use a contact mode manipulation AFM for the rotation procedure and characterize the device using Raman spectroscopy and tapping mode AFM.

The study shows that the conductance, as well as the mobility of the CNT, vary in a manner of up-down oscillations with the rotation angle. It has been found that this behaviour is more pronounced in a crossed nanotube device.

Furthermore, we examine a device consist of mono-layered Graphene, hBN and a carbon nanotube at low temperatures (<40K) and found two physical phenomena: random telegraph noise (RTN) and negative deferential resistance (NDR).

We investigate the origin of these two phenomena by exploring the dependence on the gate voltage and the temperature. Intriguing coupling is revealed between the three components of the device.