Properties of TlZnSnO film fabricated via sputtering from TlZnSnO target

TlZnSnO films, fabricated by sputtering with TlZnSnO targets composed of TlZnSnO powder, which was prepared via two-stage calcination, were analyzed. This study reports the first trial of TlZnSnO film preparation, and its optical and electrical properties. Tl atom concentrations of 0.9–1.36 at.% in the TlZnSnO films changed the bandgap between 2.83 and 3.07 eV. The obtained TlZnSnO ionization potential of 5.57–5.9 eV was slightly smaller than that of amorphous InGaZnO (a-IGZO). We also found that the conduction band was located approximately around 3 eV or lower beneath the vacuum level for each examined film; and that a deep density of state (DOS) exists near the valence band. A similar subgap DOS to that of a-IGZO existed even in TlZnSnO. However, the bandgap (2.83–3.07 eV) and donor level (31 meV) of TlZnSnO are smaller than those of a-IGZO. (paper)