Versatile Transfer of an Ultralong and Seamless Nanowire Array Crystallized at High Temperature for Use in High-Performance Flexible Devices

• Published in: ACS nano Vol. 11; no. 2; pp. 1520 - 1529
• Main Authors: Seo, Min-Ho, Yoo, Jae-Young, Choi, So-Young, Lee, Jae-Shin, Choi, Kwang-Wook, Jeong, Chang Kyu, Lee, Keon Jae, Yoon, Jun-Bo
• Format: Journal Article
• Language: English
• Published: United States American Chemical Society 28.02.2017
• Subjects: Annealing; Arrays; Barium titanates; Crystallization; Nanostructure; Nanowires; Semiconductors; Substrates; crystallization; flexible piezoelectric; high alignment; nanowire array; transfer
• ISSN: 1936-0851; 1936-086X; 1936-086X
• DOI: 10.1021/acsnano.6b06842

Nanowire (NW) transfer technology has provided promising strategies to realize future flexible materials and electronics. Using this technology, geometrically controlled, high-quality NW arrays can now be obtained easily on various flexible substrates with high throughput. However, it is still challenging to extend this technology to a wide range of high-performance device applications because its limited temperature tolerance precludes the use of high-temperature annealing, which is essential for NW crystallization and functionalization. A pulsed laser technique has been developed to anneal NWs in the presence of a flexible substrate; however, the induced temperature is not high enough to improve the properties of materials such as ceramics and semiconductors. Here, we present a versatile nanotransfer method that is applicable to NWs that require high-temperature annealing. To successfully anneal NWs during their transfer, the developed fabrication method involves sequential removal of a nanoscale sacrificial layer. Using this method, we first produce an ultralong, perfectly aligned polycrystalline barium titanate (BaTiO3) NW array that is heat treated at 700 °C on a flexible polyethylene terephthalate (PET) substrate. This high-quality piezoelectric NW array on a flexible substrate is used as a flexible nanogenerator that generates current and voltage 37 and 10 times higher, respectively, than those of a nanogenerator made of noncrystallized BaTiO3 NWs.