Series and parallel connection of individual Pd-modified ZnO nanowires for gas sensing applications

Abstract

The hydrogen gas sensing properties of nanodevices based on two ZnO nanowires (NWs) functionalized/modified with palladium (Pd/ZnO) at room temperature are studied. The main goal of the study is to find which of the connections—in series or in parallel—is more favorable to improve the properties of a double NW nanodevice in comparison with a single Pd/ZnO NW-based nanosensor. An enhancement in gas response is observed in both cases. In the case of connection in series of two NWs, it is attributed to an increased number of Schottky barriers, which are directly related to sensor response to gases. In the case of parallel connection of two NWs, higher electrical currents can flow through the device; it improves the sensor response too; in addition, this type of device can be more easily integrated in electronics due to higher currents in passive regime (in air) and is more stable.