In this work, we study and compare the photo-induced conductivity of a two-dimensional electron gas (2DEG) at the bare surface of SrTiO3 (STO) and in the heterostructure of BiFeO3 (BFO) and STO, where BFO was deposited by radio frequency magnetron sputtering. The photo-induced conductance of the BFO/STO interface shows a large increase which is 20.62 times more than the sum of photo-induced conductance from each individual BFO thin film and STO crystal. Since this photo-induced conductance of the BFO/STO heterostructure can be adjusted to become higher and lower by applying an electric field to the top surface, we attribute this large increase to the strong photo-induced electrical polarization of BFO. With the two-point setup of positive bias and negative bias, the conductivity also exhibits diode-like behavior where the forward and backward resistances are different. This work provides methods to interplay between light irradiation, electric field, and conductivity in all-oxide electronics.
Large increase in photo-induced conductivity of two-dimensional electron gas at SrTiO3 surface with BiFeO3 topping layer
Note: This paper is part of the APL Special Collection on Metal Oxide Thin-Film Electronics.
Peerawat Laohana, Siwat Polin, Warakorn Jindata, Aissara Rasritat, Tanachat Eknapakul, Pimchanok Leuasoongnoen, Supree Pinitsoontorn, Pattanaphong Janphuang, Wittawat Saenrang, Worawat Meevasana; Large increase in photo-induced conductivity of two-dimensional electron gas at SrTiO3 surface with BiFeO3 topping layer. Appl. Phys. Lett. 12 December 2022; 121 (24): 241601. https://doi.org/10.1063/5.0123578
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