posted on 2023-01-04, 09:49authored byKonstantina Iordanidou, Richa Mitra, Naveen Shetty, Samuel Lara-Avila, Saroj Dash, Sergey Kubatkin, Julia Wiktor
Heterostacks consisting
of low-dimensional materials are attractive
candidates for future electronic nanodevices in the post-silicon era.
In this paper, using first-principles calculations based on density
functional theory (DFT), we explore the structural and electronic
properties of MoTe2/ZrS2 heterostructures with
various stacking patterns and thicknesses. Our simulations show that
the valence band (VB) edge of MoTe2 is almost aligned with
the conduction band (CB) edge of ZrS2, and (MoTe2)m/(ZrS2)m (m = 1, 2) heterostructures exhibit the long-sought
broken gap band alignment, which is pivotal for realizing tunneling
transistors. Electrons are found to spontaneously flow from MoTe2 to ZrS2, and the system resembles an ultrascaled
parallel plate capacitor with an intrinsic electric field pointed
from MoTe2 to ZrS2. The effects of strain and
external electric fields on the electronic properties are also investigated.
For vertical compressive strains, the charge transfer increases due
to the decreased coupling between the layers, whereas tensile strains
lead to the opposite behavior. For negative electric fields a transition
from the type-III to the type-II band alignment is induced. In contrast,
by increasing the positive electric fields, a larger overlap between
the valence and conduction bands is observed, leading to a larger
band-to-band tunneling (BTBT) current. Low-strained heterostructures
with various rotation angles between the constituent layers are also
considered. We find only small variations in the energies of the VB
and CB edges with respect to the Fermi level, for different rotation
angles up to 30°. Overall, our simulations offer insights into
the fundamental properties of low-dimensional heterostructures and
pave the way for their future application in energy-efficient electronic
nanodevices.