Coaxial p-Si/n-ZnO nanowire heterostructures for energy and sensing applications

Radial p–n nanowire heterojunction devices represent a favorable geometry to maximize the interfacial area and charge carrier separation due to the built-in field established across the junction. This report presents the functional characterization of a heterojunction device based on a single coaxial p-Si/n-ZnO nanowire that was integrated in a circuit by FIB nanolithography to study the electrical properties. Specifically, their photovoltaic and gas sensing performances were preliminary assessed. The gas sensing response of the p–n heterojunction could be usefully modulated by controlling the bias currents through the device, showing a complementary functionality of these nanoarchitectured devices.

► Coaxial p-Si/n-ZnO core/shell nanowires (NWs) were produced. ► Heterojunction devices based on one single NW were produced by FIB nanolithography. ► These devices displayed photovoltaic and gas sensing properties. ► Non-linear I–V characteristic allowed us to tune their sensibility to gases by modulating the bias.