Transparent and Flexible Capacitors with an Ultrathin Structure by Using Graphene as Bottom Electrodes
Tao Guo,
Guozhen Zhang,
Xi Su,
Heng Zhang,
Jiaxian Wan,
Xue Chen,
Hao Wu,
Chang Liu
Affiliations
Tao Guo
Key Laboratory of Artificial Micro- and Nano-Structures of Ministry of Education, and School of Physics and Technology, Wuhan University, Wuhan 430072, China
Guozhen Zhang
Key Laboratory of Artificial Micro- and Nano-Structures of Ministry of Education, and School of Physics and Technology, Wuhan University, Wuhan 430072, China
Xi Su
Key Laboratory of Artificial Micro- and Nano-Structures of Ministry of Education, and School of Physics and Technology, Wuhan University, Wuhan 430072, China
Heng Zhang
Key Laboratory of Artificial Micro- and Nano-Structures of Ministry of Education, and School of Physics and Technology, Wuhan University, Wuhan 430072, China
Jiaxian Wan
Key Laboratory of Artificial Micro- and Nano-Structures of Ministry of Education, and School of Physics and Technology, Wuhan University, Wuhan 430072, China
Xue Chen
Key Laboratory of Artificial Micro- and Nano-Structures of Ministry of Education, and School of Physics and Technology, Wuhan University, Wuhan 430072, China
Hao Wu
Hubei Nuclear Solid Physics Key Laboratory, and School of Physics and Technology, Wuhan University, Wuhan 430072, China
Chang Liu
Key Laboratory of Artificial Micro- and Nano-Structures of Ministry of Education, and School of Physics and Technology, Wuhan University, Wuhan 430072, China
Ultrathin, transparent and flexible capacitors using graphene as the bottom electrodes were directly fabricated on polyethylene naphthalate (PEN) substrates. ZrO2 dielectric films were deposited on the treated surface of graphene by atomic layer deposition (ALD). The deposition process did not introduce any detectible defects in the graphene, as indicated by Raman measurements, guaranteeing the electrical performances of the graphene electrodes. The Aluminum-doped zinc oxide (AZO) films were prepared as the top electrodes using the ALD technique. The capacitors presented a high capacitance density (10.3 fF/μm2 at 10 kHz) and a relatively low leakage current (5.3 × 10−6 A/cm2 at 1 V). Bending tests revealed that the capacitors were able to work normally at an outward bending radius of 10 mm without any deterioration of electrical properties. The capacitors exhibited an average optical transmittance of close to 70% at visible wavelengths. Thus, it opens the door to practical applications in transparent integrated circuits.
