Pixel analysis of a force-sensing device based on individually contacted vertical piezoelectric nanowires

We report on the static finite element (FEM) simulations of the representative pixel of a force-sensing device, with the aim of predicting the influence of technically tunable parameters on pixel response. This pixel was based on an individually contacted vertical nanowire. It was found that piezopotential collection efficiency was higher for thinner seed-layers, reaching up to 69 % for a 5 nm-thick layer. The degradation resulting from a gap between the NW and its contacts was quantified, lowering this value to 33 % for a 3 nm gap. The values chosen for technological parameters were based on experimental results and set to a range of plausible values for selective growth of ZnO nanowires on pre-patterned substrates. Our results provide important guidelines for the optimization of sensor pixel piezoelectric response, with resulting constraints on NW growth and substrate patterning.