Abstracts Book - IMRC 2018

• SC4-P016
MULTILAYER DEVICE FROM VERTICAL GRAPHENE/H-BN
HETEROSTRUCTURES
Carlos Iván Cabrera 1 , David Armando Contreras Solorio 1 , Luis Hernández 2 , Agustín Enciso 1 ,
Carlos Rodríguez 2
1
Universidad Autónoma de Zacatecas, Academic Unit of Physics, Mexico. 2 Universidad de La
Habana, Faculty of Physics, Cuba.
Since its scientific discovery, graphene has become the center of attention as a
new type of material, in which electron transport is governed by a Dirac-type
wave equation. It is profitable to consider how 2D-2D tunneling could be used
in this new electronic system. In recent years, a number of research groups have
published theoretical and/or experimental results, relating to vertical grapheneinsulatorgraphene
tunneling structures. This type of device works based on
quantum tunneling across a thin insulating channel barrier such as layer of h-
BN, sandwiched between a pair of graphene contacts
In the present work, the tunneling current in a vertical graphene
heteroestructure device is amplified. The doping in the graphene layers is fitted
in such a way that the Diracs point are line up for achieving a high resonant
current peak. In addition, analytical and numerical expressions are derived for
the current-voltage characteristics in the heterostructure. The effect of both
graphene layer sets and rotational aligment on tunneling currents is discussed.
We find the transition strength between layers is grater for state above the
Diracs point.
A new effect has been added to the list of graphene properties, namely, the
ability to generate multiple hot carriers with energy above the Fermi level a
single absorbed photon as a result of so-called impact excitation processes
taking part in the energy relaxation of the primary photoexcited carriers. This
carrier multiplication is predicted to be particularly effective in graphene, by
virtue of its linear band structure combined with strong electron−electron
scattering and weak electron−phonon cooling, and represents a very interesting
approach to efficiently convert light energy into electronic excitations. Here we
focus on the photoexcitation cascade and impact excitation in doped graphene
in order to evaluate the photocurrent. The absorption coefficient and
photocurrent are calculated in graphene/h-BN heterostructure. It shows that