This work reports the formation process and the resulting optical properties of AlTiO selective transmitting layers. The
AlTiO layers were deposited by reactive sputtering from Al and Ti targets in oxygen atmosphere. The compositions and
thicknesses of the AlTiO layers were controlled by varying deposition parameters, and corresponding changes in
transmittance and reflectance were measured. The reflectance decreased and then increased with increasing wavelength,
and its minimum depending on the composition and thickness of AlTiO was found at a wavelength ranging from 380 to
750nm. The raised reflectance in the long wavelength regime suggests the possible use of the sputter-deposited AlTiO
layers as a selective transmitting layer in high efficient and semitransparent Si thin film solar cells.