Positron Structural Analysis of ScN Films Deposited on MgO Substrate
Joris More-Chevalier, Lukáš Horák, Stanislav Cichoň, Petr Hruška, Jakub Čı́žek, Maciej Oskar Liedke, Maik Butterling, A. Wagner, J. Bulı́ř, Pavel Hubı́k, Zuzana Gedeonová, J. Lančok
Abstract
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 2.530.01 eV, and 2.560.01 eV which has been measured on ScN films of 118 nm and 950 nm thicknesses, respectively.