Flexible piezoelectric nanogenerators based on silicon nanowire/α-quartz composites for mechanical energy harvesting

The α-quartz could grow at the interface of silicon nanowires (SiNWs) after thermal treatment. The SiNW/α-quartz composite was utilized as an active layer to fabricate piezoelectric nanogenerators on a flexible polyethylene terephthalate substrate, capable of converting mechanical energy into electricity. An insulative Al2O3 layer was designed to fill the gaps of the composite to avoid the leakage of current by atomic layer deposition and reactive ion etching process. The flexible nanogenerators produced an average short-circuit current of 0.6 μA under the force of 60 N and the maximum power value reached about 380 nW with the load resistance of 20 MΩ.