[15a-2L-1~12] 6.1 Ferroelectric thin films

△ [15a-2L-8] Photovoltaic Properties under Visible Light Irradiation of LiNbO₃Thin Films

〇atsushi inuzuka¹, Shusuke Takahashi¹, Ryotaro Inoue², Yuji Noguchi¹, Masaru Miyayama¹ (1.Tokyo Univ., 2.Nihon Univ.)

Keywords:thin films of ferroelectrics,lithium niobate,photovoltaic properties under visible light irradiation

Thin films of heavily-Mn-doped lithium niobate were prepared by a pulsed laser deposition method and the photovoltaic properties were measured under visible light irradiation. The films show an open circuit voltage (V_OC) as high as 90 V, which is the highest for ferroelectric films, as far as we aware. We demonstrate that the remarkable photovoltaic voltage is derived from visible light absorption and subsequent charge separation through an occupied gap state of Mn_Li²⁺. These results present materials design of ferroelectrics: the introduction of occupied gap states in near the middle of band gap is effective in enhancing photovoltaic properties under visible light irradiation.