Near-ultraviolet photodetector based on hexagonal TmFeO3 ferroelectric semiconductor thin film with photovoltaic and pyroelectric effects

The switchable ferroelectric photovoltaic (FPV) effect facilitates application of multifunctional photoelectric devices. The drawback of the FPV effect is that it generates a very low photocurrent in highly insulated ferroelectric materials. In contrast, the light-induced pyroelectric effect enhances photoelectric performance. Both effects strongly depend on the ferroelectric polarization of the material. In this study, we fabricated and characterized a near-ultraviolet photodetector consisting of a Pt/hexagonal TmFeO3/Pt heterojunction. The switchable FPV and light-induced pyroelectric effects are both observed in a hexagonal TmFeO3 ferroelectric semiconductor film. An additional potential arises from the light-induced pyroelectric effect, which strongly depends on the light intensity. The Schottky barrier height can be modulated by both the poling electric field and light-induced pyroelectric potential. Increasing the power density above the threshold leads to switchable polarization via the light-induced pyroelectric potential. The coexistence of photovoltaic and pyroelectric effects in the hexagonal TmFeO3 ferroelectric semiconductor makes it possible to develop electronic, thermal, and optical sensors as well as energy conversion devices.