High-quality-factor flexible and transparent capacitors with Cr-Au nanomeshes as bottom electrodes

Flexible and transparent capacitors have been fabricated on polyethylene naphthalate (PEN) substrates. The Cr-Au nanomeshes, ZrO₂, and aluminum-doped zinc oxide (AZO) films were prepared in sequence as bottom electrodes, dielectric layers and top electrodes. A high quality factor of 82 was obtained, nearly 4.9 times larger than that ever reported, which directly indicates much lower power consumption. The flexible capacitors can normally work at a bending radius of 7 mm without any loss of electrical performance, and even maintain electrical characteristics after cyclical bending tests. Moreover, a high capacitance density of 12.3 fF μm^-2 and an ultralow leakage current of 1.5 × 10^-8 A cm^-2 at 1 V have been achieved. Transmittance measurements indicate that the capacitors represent an average optical transmittance of over 50% at a visible region. This is, therefore, a dramatic step toward real applications in flexible and transparent integrated circuits.