Epitaxial potassium niobate (KNbO3) thin films have been deposited on
KTaO3 (100), MgAl2O4 (100), and MgO (100) substrates using ion-beam sp
utter deposition. X-ray-diffraction results show that KNbO3 films have
orthorhombic (110) orientation on all three substrates. Rutherford ba
ckscattering channeling analysis of KNbO3 films on KTaO3, MgAl2O4, and
MgO exhibits minimum scattering yields (chi(min)) of 7%, 9%, and 18%
for the Nb peak, respectively. This illustrates how the quality of epi
taxy improves as the lattice mismatch decreases. Prism-coupling measur
ements reveal near-bulk refractive indices of about 2.27 for TE modes
and 2.22 for TM modes for films on each substrate.