Figure 6. Resistance change of metal thin film against consecutive mechanical strain.

(a) Schematic of device structure and experiment. A thin layer of aluminum (thickness: 300 nm; length: 2 cm; width: 0.2 cm) was deposited on a Scotch tape attached on office paper and a polyimide film. Detailed substrate structure is shown in Fig. 5(a). (b) Normalized resistance data of the aluminum layer as a function of the number of bendings. Electrical measurements were performed while the sample was flat. As explained in Fig. 5, the adhesive layer of the Scotch tape relaxes the strain applied to the top; therefore, the aluminum layer on Scotch tape exhibits much less increase on its resistance value against mechanical strain than the aluminum on the regular polyimide substrate.