Monolayer (ML) SnSe,
a p-type IV–VI semiconductor, has drawn
tremendous attention because of its chemical stability, high electrostatic
gating efficiency, and carrier mobility, and it has been synthesized
in different ways. We have comprehensively investigated the properties
of the interfaces between ML SnSe and some regular metals by using
first-principles calculations. Metallization of ML SnSe appears in
ML SnSe–Ag, −Al, −Au, −Cu, and −Cr
systems. Lateral n-type Schottky contacts with electron Schottky barrier
heights of 0.42 and 0.32 eV are formed, respectively, when ML SnSe
contacts with metals Ag and Al. Also, a lateral p-type quasi-ohmic
contact with a hole Schottky barrier height of 0.02 eV is formed when
ML SnSe contacts with metal Au. Surprisingly, ohmic contacts are formed
when ML SnSe contacts with metals Cr and Cu. Our research not only
has a deep understanding of the characteristics of the interfaces
between ML SnSe and the metals but also offers a reference in the
electrode selection for ML SnSe devices.