Synthesis, functionalization, and environmental stabilization of ZnO nanobridge transducers for gas and liquid-phase sensing

Three methods of functionalizing ZnO NW surfaces with biotin were demonstrated. Biotinylated ZnO NWs were found to dissolve during exposure to deionized (DI) water, so a chemical vapor deposition (CVD) process was developed for parylene-A, a common moisture barrier with an amine group which allows further functionalization. Parylene-A coated ZnO NWs were found to be resistant to dissolution. Electrical measurements on parylene-A coated nanobridge devices showed normal operation with higher dark current and an attenuated response to UV and O2, indicating the ability to modulate environmental sensitivity. This work demonstrates the novel use of parylene-A coatings as an encapsulation layer as well as a potential starting platform for general functionalization of ZnO NW devices for selective sensing.