Optical and structural characteristics of Sb-doped SnO ₂ thin films grown on Si (111) substrates by Sol-Gel technique

The optical and structural characteristics of Sb-doped SnO ₂ films grown on Si (111) substrates by modified sol-gel technique have been investigated. The films are both polycrystalline and retain the SnO ₂ peaks of the rutile phase corresponding to (110), (101), (211) and (310) without any other phases appearing. X-ray photoelectron spectroscopy shows the peaks corresponding to the Sn 3d _5/2, the O 1s, and the Sb 3d _5/2 states. Refractive indices n, and extinction coefficients k, as functions of the incident photon energy were obtained for the films by spectroscopic ellipsometry measurement, and the refractive indices were from 1.95 to 1.50 at 2.6 eV with increasing Sb content. The optical constants, n and k, of the films can be controlled by variable Sb content. These results are important for the applications in integrated optical devices.