Depletion layer and dimensionality of ZnO nanostructures

In this work we present the growth of both onedimensional (1D) and two-dimensional (2D) zinc oxide (ZnO) nanostructures. The thickness (diameter in the case of nanowires) was varied by changing the growth parameters. ZnO nanowires with an average diameter of 80 - 250 nm and nanosheets with an average thickness of 70 - 360 nm were obtained. Both kinds of nanostructure have been used as conductometric gas sensors for liquid petroleum gas (LPG). The sensing performance of the 1D-and 2D-sensors are investigated as a function of their dimensionality. Basically, the depletion layer affects two dimensions of nanowires but only one of nanosheets, and this significantly improves the sensor response of 1D- nanostructures. On the other hand two-dimensional nanostructures´ larger cross-section increases their base current, thus lowering their limit of detection.