  Al2O3 is a potential dielectric material for metal-oxide-semiconductor (MOS)
devices. Al2O3 films deposited on semiconductors usually exhibit amorphous due
to lattice mismatch. Compared to two-dimensional graphene, MoS2 is a typical
semiconductor, therefore, it has more extensive application. The
amorphous-Al2O3/MoS2 (a-Al2O3/MoS2) interface has attracted people's attention
because of its unique properties. In this paper, the interface behaviors of
a-Al2O3/MoS2 under non-strain and biaxial strain are investigated by first
principles calculations based on density functional theory (DFT). First of all,
the generation process of a-Al2O3 sample is described, which is calculated by
molecular dynamics and geometric optimization. Then, we introduce the band
alignment method, and calculate band offset of a-Al2O3/MoS2 interface. It is
found that the valence band offset (VBO) and conduction band offset (CBO)
change with the number of MoS2 layers. The dependence of leakage current on the
band offset is also illustrated. At last, the band structure of monolayer MoS2
under biaxial strain is discussed. The biaxial strain is set in the range from
-6% to 6% with the interval of 2%. Impact of the biaxial strain on the band
alignment is investigated.
