Electrical and optical properties of scandium nitride nanolayers on MgO (100) substrate

Scandium nitride (ScN) is a rocksalt-structure semiconductor that has attracted attention for its potential applications in thermoelectric energy conversion devices, as a semiconducting component in epitaxial metal/semiconductor superlattices. ScN nanolayers of 30 nm thickness were deposited on MgO (001) substrate by reactive sputtering. Epitaxial growth of ScN(002) was observed with a mosaicity between grains around the {002} growth axis. Both direct band gaps theoretically predicted were measured at 2.59 eV and 4.25 eV for the energy gaps between the valence band and the conductance band at the X point and the Γ point respectively. Electrical and optical properties were observed to be strongly influenced by the crystalline order and the carrier concentration.