Current self-complianced and self-rectifying resistive switching in Ag-electroded single Na-doped ZnO nanowires.

We demonstrate current self-complianced and self-rectifying bipolar resistive switching in an Ag-electroded Na-doped ZnO nanowire device. The resistive switching is controlled by the formation and rupture of an Ag nanoisland chain on the surface along the Na-doped ZnO nanowire. Na-doping plays important roles in both the self-compliance and self-rectifying properties.

Resistive switching in single epitaxial ZnO nanoislands.

Resistive memory is one of the most promising candidates for next-generation nonvolatile memory technology due to its variety of advantages, such as simple structure and low-power consumption. Bipolar resistive switching behavior was observed in epitaxial ZnO nanoislands with base diameters and heights ranging around 30 and 40 nm, respectively. All four different states (initial, electroformed, ON, and OFF) of the nanoscale resistive memories were measured by conductive atomic force microscopy immediately after the voltage sweeping was performed. Auger electron spectroscopy and other experiments were also carried out to investigate the switching mechanism. The formation and rupture of conducting filaments induced by oxygen vacancy migration are responsible for the resistive switching behaviors of ZnO resistive memories at the nanoscale.

Carbon nanotube memory by the self-assembly of silicon nanocrystals as charge storage nodes.

A memory structure based on self-aligned silicon nanocrystals (Si NCs) grown over Al(2)O(3)-covered parallel-aligned carbon nanotubes (CNTs) by gas source molecular beam epitaxy is reported. Electrostatic force microscopy characterizations directly prove the charging and discharging of discrete NCs through the Al(2)O(3) layer covering the CNTs. A CNT field effect transistor based on the NC/CNT structure is fabricated and characterized, demonstrating evident memory characteristics. Direct tunneling and Fowler-Nordheim tunneling phenomena are observed at different programming/erasing voltages. Retention is demonstrated to be on the order of 10(4) s. Although there is still plenty of room to enhance the performance, the results suggest that CNT-based NC memory with diminutive CNTs and NCs could be an alternative structure to replace traditional floating gate memory.

Electrically pumped waveguide lasing from ZnO nanowires.

Ultraviolet semiconductor lasers are widely used for applications in photonics, information storage, biology and medical therapeutics. Although the performance of gallium nitride ultraviolet lasers has improved significantly over the past decade, demand for lower costs, higher powers and shorter wavelengths has motivated interest in zinc oxide (ZnO), which has a wide direct bandgap and a large exciton binding energy. ZnO-based random lasing has been demonstrated with both optical and electrical pumping, but random lasers suffer from reduced output powers, unstable emission spectra and beam divergence. Here, we demonstrate electrically pumped Fabry-Perot type waveguide lasing from laser diodes that consist of Sb-doped p-type ZnO nanowires and n-type ZnO thin films. The diodes exhibit highly stable lasing at room temperature, and can be modelled with finite-difference time-domain methods.