Field emission from crystalline copper sulphide nanowire arrays

Straight crystalline copper sulphide $({\mathrm{Cu}}_2\mathrm{S})$ nanowire arrays have been grown by using a simple gas–solid reaction at room temperature. These were demonstrated to exhibit semiconductor properties. Field emission was observed at a field of $\text{∼6\hspace{0.17em}}\mathrm{MV}/\mathrm{m},$ and its current-field characteristics deviate from Fowler–Nordheim theory, i.e., showing a nonlinear Fowler–Nordheim plot. The uniform emission from the whole arrays was observed using transparent anode technique, and their variation with applied field was recorded. The emission from individual nanowires was also studied using a field emission microscope, and was found to consist of a number of spatially resolved diffuse spots. Finally, stable emission current at different levels and over time was recorded. These findings indicate that semiconductor nanowires as cold cathode have a potential future, worthy of further comprehensive investigation. The technical importance of using semiconductor nanowires as cold cathode emitter is given.