Freestanding SrNbO₃ membranes as flexible transparent conductors

The interest in flexible transparent conductors is increasing due to their potential applications in flexible optoelectronics devices. While tin-doped indium oxides are the most widely used transparent conductors, their brittleness hampers their utilization in flexible devices. On the other hand, freestanding metallic oxide films can be an alternative candidate for realizing flexible transparent conductors, given their large stretchability ^[1] and super-elasticity ^[2]. Here, we fabricate millimeter-sized transparent conductive SrNbO₃ membranes using water-soluble aluminate sacrificial layers ^[3]. In SrNbO₃, the large electron correlation and high transition energy from the O 2p to Nb 4d orbitals lead to a wide transparency range ^[4,5]. The sheet resistance (R_S) of the obtained SrNbO₃ (9.2 nm) membrane is 170 Ω/sq and the transmittance (T) is ~ 90 % at 550 nm at room temperature. The figure of merit (T¹⁰/R_S) for the transparent conductor of the membrane is 1.5 10^-3 Ω^-1, which is comparable to other transparent conductors. The smooth surface of the membrane (rms < 1.0 nm) results in a good adherence to other flexible substrates. The fabrication process, as well as the transport and transmittance properties of the membrane, will be discussed in detail.



[1] S. S. Hong et al., Science 368, 6486 (2020).

[2] G. Dong et al., Science 366, 475 (2019).

[3] D. Lu et al., Nature Materials 15, 1255 (2016).

[4] L. Zhang et al., Nature Materials 15, 204 (2016).

[5] Y. Park et al., Communications Physics 3, 102 (2020).