DIRECT-WRITE e-BEAM PERIODICALLY POLED ～400 nm DOMAINS IN LITHUIM NIOBATE THIN FILMS GROWN BY LIQUID PHASE EPITAXY

摘要

We demonstrate sub-micron ferroelectric domain engineering in liquid phase epitaxy (LPE) LiNbO_3 thin films grown on LiNbO_3 and LiTaO_3 substrates using a direct-write electron beam poling method. LiNbO_3 thin films of several-micron thicknesses were grown using a flux melt of 20 mol% LiNbO_3—80 mol% LiVO_3. To engineer domain structures in Z~- oriented LPE LiNbO_3 films, a direct-write electron beam poling method was implemented. We achieved 300—400 nm wide domains spanning over 50 μm with a period of 1.1 μm. It is also shown that we can engineer the domain structure of LPE LiNbO_3 films by using direct e-beam poling, even though the domain orientations of the film and the substrate are of opposite polarity. By comparing the e-beam poling behavior in a congruent LiNbO_3 single crystal and a LPE LiNbO_3 film, it is shown that LPE LiNbO_3 supports a much enhanced periodically poled structure than bulk single crystal material.