Conductivity and photoconductivity in undoped ZnSe nanowire array

Arrays of free-standing ZnSe nanowires with the length of $8–10\mu \mathrm{m}$ and diameters of $80–150\mathrm{nm}$ were fabricated by Au-catalyzed vapor-liquid-solid growth. Current-voltage characteristics of the arrays over the temperature interval of $90–400\mathrm{K}$ showed a superlinear character. The differential conductance varied between two saturating regimes at low and high biases, respectively. This behavior was explained using a model of nonuniform wires with concentration fluctuations along them. The nanowire photoconductivity had a spectral edge corresponding to the ZnSe band gap and a strong frequency dispersion, presumably due to carrier capture by deep centers.