A method for modifying the surface free energy of lithium tantalate (LT) ferroelectric crystals is reported. Ultraviolet illumination and low-energy electron irradiation have been used for tuning the surface free energy (wettability) resulting in a wide range of contact angles (6 deg to 87 deg). The ultraviolet (UV) illumination makes the LT crystal surface superhydrophilic while the low-energy electron irradiation decreases the surface wetting. Fabrication of various wetting configurations allows demonstration of high-quality direct bonding of LT plates with hydrophilic polar faces.
- Direct bonding
- Surface free energy