Photoactivation of Sol-Gel Precursors for the Low-Temperature Preparation of PbTiO_3 Ferroelectric Thin Films

摘要

PbTiO_3 thin films have been prepared by ultraviolet (UV) -assisted rapid thermal processing (RTP) (photochemical solution deposition) following a sol-gel method. To prepare photo-sensitive sols, two types of photo-initiators compounds, N-methyldiethanolamine and propylenaldehyde, have been incorporated into the system. The effect of the type and amount of photo-initiator on the UV light absorption of the respective precursor solutions was studied. At 400℃, the PbTiO_3 perovs-kite phase was observed by X-ray diffraction in the films. These films show an improved ferroelectric response when they are UV-irradiated during the anneah'ng as compared with those nonirradiated. Moreover, properties are significantly better in PbTiO_3 thin films prepared by using N-methyldiethanolamine as a photoinitiator. Thus, films prepared from sols containing A'-methyldiethanolamine, UV-irradiated and crystallized by RTP at 400℃, show well-defined ferroelectric hysteresis loops with values of remnant polarization and coercive field of P_r～11.9 μC/cm~2 and E_c～235 kV/cm, respectively.