Indium tin oxide (ITO, tin-doped
indium oxide) has been widely
used in optoelectronic and other research fields because of its excellent
electrical conductivity. However, there is a lack of systemic research
on the influence of crystal orientation on the electrical properties
of epitaxial ITO films. In this work, the epitaxial ITO films were
deposited on low index planes of yttria-stabilized zirconia substrates
by direct current magnetron sputtering at different oxygen partial
pressures ranging from 0 to 3 Pa. The carrier concentration of the
ITO film decreased with the increase of the oxygen partial pressure
and further leading to the increase of overall resistivity. In addition,
we also found that the Hall mobilities of ITO (100) films rapidly
decreased with the oxygen partial pressure, while the Hall mobilities
of ITO (111) films remained unchanged. The anisotropy of the carrier
mobility was the main factor for the resistivity difference of ITO
films with different orientations at high oxygen partial pressure.