Photon-induced tunneling in graphene-boron nitride-graphene heterostructures

Graphene is a material that has generated much interest due to its many unique electronic and optical properties. In this work, we present optoelectronic measurements performed on ultrathin graphene-boron nitride-graphene heterostructures. Scanning photocurrent spectroscopy allows us to explore the tunneling behavior of these devices as a function of both photon energy and bias voltage. Tunneling through the boron nitride insulator is found to be dramatically enhanced by the presence of light, showing a high-bias behavior that can be well described using Fowler-Nordheim tunneling. These measurements indicate that tunneling is dominated by photoexcited positive charge carriers (holes) with an intrinsic barrier height and effective mass of 1.33eV and 1.1 9me, respectively. These numbers agree well with theoretical calculations of the offset between the top of the valence band in boron nitride and the charge neutrality point in graphene, and the effective mass of holes in boron nitride. Moreover, a peak in the conductance was observed at zero bias voltage, indicating the presence of thermionic emission near the charge neutrality point..

Department dc:contributor.department

Massachusetts Institute of Technology. Department of Physics.

Grantor dc:publisher

Massachusetts Institute of Technology

Year dc:date.issued

2013

Author dc:creator

• Nair, Nityan

Advisor dc:contributor.advisor

• Pablo Jarillo-Herrero.

• Physics.

Statement dc:rights

• M.I.T. theses are protected by copyright. They may be viewed from this source for any purpose, but reproduction or distribution in any format is prohibited without written permission. See provided URL for inquiries about permission.

Licence dc:rights.uri

• http://dspace.mit.edu/handle/1721.1/7582

Language dc:language.iso

eng

Handle dc:identifier.uri

http://hdl.handle.net/1721.1/83803

OAI identifier oai:identifier

oai:dspace.mit.edu:1721.1/83803