Search

Scandium nitride (ScN) is a semiconductor with a rocksalt-structure that has attracted attention for its potential applications in thermoelectric energy conversion devices, as a semiconducting component in epitaxial metal/semiconductor superlattices. Two ScN films of 118 nm and 950 nm thicknesses were deposited at the same conditions on MgO (001) substrate by reactive magnetron sputtering. Poly-orientation of films was observed with first an epitaxial growth on MgO and then a change in the orientation growth due to the decrease of the adatom mobility during the film growth. Positron lifetime measurements showed a high concentration of nitrogen vacancies in both films with a slightly higher concentration for the thicker ScN film. Presence of nitrogen vacancies explains the values of direct band gaps of 2:53±0:01 eV, and 2:56±0:01 eV which has been measured on ScN films of 118 nm and 950 nm thicknesses, respectively. [ABSTRACT FROM AUTHOR]

• Deposition and growth of ScN film on crystalline and amorphous substrates. • XPS Study of ScN film oxidation and stability – deposition and post-deposition effects. • Correlation between crystalline quality and oxidation process of ScN films exposed to air. • ScN undergoes quick surface oxidation which follows crystalline defects in the bulk. • Electrical properties, and to a lesser extent optical properties, are impaired by the post-deposition oxidation. Oxidation and hydrolysis are two spontaneous reactions occurring when scandium nitride (ScN) is exposed to air (oxygen and humidity). In order to evaluate the detrimental effect of the oxidation on functional properties of the material, ScN films were prepared under ultrahigh vacuum conditions at 700 °C onto two different substrates; crystalline MgO(0 0 1) and amorphous fused silica. X-ray Photoelectron Spectroscopy analysis was performed to study the oxidation reactions. The study also employed vacuum transferred pristine samples. Crystalline quality and oxidation resistance were found to be strongly correlated. Degradation of electrical and optical properties was observed for polycristalline films prepared on fused silica. On the other hand, highly ordered crystalline films grown on MgO(0 0 1) demonstrated surface passivation preventing further progress of the oxidation. Post-deposition exposure to air was found to be a principal source of the observed oxidation. [ABSTRACT FROM AUTHOR]