Structural, electrical and optical properties of Sn doped ZnO films deposited by atomic layer deposition

Abstract

Tin doped ZnO (SnZO) films were deposited on the Si and K-9 glass substrate by atomic layer deposition method using ozone as oxygen source. The influences of Sn concentration on composition, structural, electrical and optical properties of ZnO films have been investigated. All the films exhibited a highly preferential c-axis orientation. It was concluded that Sn atoms predominantly go to the Zn lattice sites in the Sn4+ state and therefore Sn acts as an effective donor base on XPS and Hall measurements. A minimum resistivity of 9.5×10-4 Ω·cm, with a carrier concentration of 3.2×1020cm-3, was obtained for film deposited with the Sn concentration of 1.8at%. The optical transmittance of SnZO films were over 85% in the visible region and the optical bandgap of the films increased from 3.26 eV to 3.54 eV with increasing of Sn concentration from 0 to 5.7at%.