Fig. 3

Design approaches for flexible and stretchable electronics. a SEM images of a Si NM, to emphasize its high degree of mechanical flexibility, by virtue of its thin geometry. Reprinted with permission from Rogers et al.³⁴ Copyright 2011 Nature Publishing Group. b Flexible Si NRs for transistors. Reprinted with permission from Mack et al.⁵³ Copyright 2006 American Institute of Physics Journals. c Stretchable Si NRs, formed in a periodic wavy structure and bonded to an elastomer substrate. Reprinted with permission from Khang et al.⁷⁶ Copyright 2006 American Association for the Advancement of Science. d Controlled buckling of Si NRs by lithographically defined adhesion sites to an underlying elastomer. Reprinted with permission from Sun et al.⁷⁷ Copyright 2006 Nature Publishing Group. e Fractal serpentine design concepts for stretchable electronics including the design patterns (top) and corresponding MicroXCT images of the patterns after stretching. The uniaxial prestrains are 55%, 75%, 40%, and 35% from left to right, respectively. Reprinted with permission from Fan et al.⁷⁹ Copyright 2014 Nature Publishing Group