Lattice and electronic structure of ScN observed by angle-resolved photoemission spectroscopy measurements

Scandium nitride (ScN) has recently attracted much attention for its potential applications in thermoelectric energy conversion, as a semiconductor in epitaxial metal/semiconductor superlattices, as a substrate for GaN growth, and alloying it with AlN for 5G technology. This study was undertaken to better understand its stoichiometry and electronic structure. ScN (100) single crystals 2 mm thick were grown on a single crystal tungsten (100) substrate by a physical vapor transport method over a temperature range of 1900-2000 & DEG;C and a pressure of 20 Torr. The core level spectra of Sc 2p(3/2,1/2) and N 1s were obtained by x-ray photoelectron spectroscopy (XPS). The XPS core levels were shifted by 1.1 eV toward higher values as the [Sc]:[N] ratio varied from 1.4 at 1900 & DEG;C to & SIM;1.0 at 2000 & DEG;C due to the higher binding energies in stoichiometric ScN. Angle-resolved photoemission spectroscopy measurements confirmed that ScN has an indirect bandgap of & SIM;1.2 eV. Published under an exclusive license by AIP Publishing.