Electronic properties of the SnSe-metal contacts: First-principles study

The geometries and electronic properties of SnSe/metal contact have been investigated using first-principles calculation. It is found that the geometries of monolayer SnSe were affected slightly when SnSe adsorbs on M (M=Ag, Au, Ta) substrate. Compared with the corresponding free-standing monolayer SnSe, the adsorbed SnSe undergoes a semiconductor-to-metal transition. The potential difference Δ V indicates that SnSe/Ta contact is the best candidate for the Schottky contact of the three SnSe/M contacts. Two types of current-in-plane (CIP) structure, where a freestanding monolayer SnSe is connected to SnSe/M, are identified as the n-type CIP structure in SnSe/Ag contact and p-type CIP structure in SnSe/Au and SnSe/Ta contact. The results can stimulate further investigation for the multifunctional SnSe/metal contact.