Cu2O Heterostructured GaN Thin Film and GaN Nanowire Piezoelectric Nanogenerators

Herein, a c-plane GaN thin film (TF) and c-axis GaN nanowires are grown using metal-organic chemical vapor deposition (MOCVD) and then utilized in the fabrication of piezoelectric nanogenerators (PENGs). The piezoelectric performance of GaN-based PENGs is tuned by sputtering a resistive layer of Cu2O on GaN TFs and nanowires. A significant enhancement in the piezoelectric output of a Cu2O-coated GaN TF-based PENG is observed compared with that of a pristine GaN TF-based PENG. The enhanced output is attributed to the high resistivity of Cu2O, which is controlled by conducting Cu2O sputtering in "0" sccm oxygen flow. Furthermore, a GaN/Cu2O core-shell nanowire-based PENG is fabricated to enhance the flexibility and stability of nanogenerators.