CdMnS thin films grown on indium tin oxide substrate exhibit a ferroelectric property. The remnant polarization of CdMnS films was around $0.025\mu \mathrm{C}∕{\mathrm{cm}}^2$ for 10% of manganese with a sustained polarization endurance for several cycles. Persisting and highly reproducible bistable switching of about five orders in magnitude between low and high impedance states was observed in current voltage measurements. Nondestructive readout measurement with a short pulse width of $20\mu \mathrm{s}$ resulted in a resistance difference of two orders between two read levels with a good retention time. Possible use of CdMnS for nonvolatile memory applications is explored.

The article presents, using Bi doped ZnO, an example of a heavy ion doped oxide semiconductor, highlighting a novel p-symmetry interaction of the electronic states to stabilize ferromagnetism. The study includes both ab initio theory and experiments, which yield clear evidence for above room temperature ferromagnetism. ZnBi_xO_1−x thin films are grown using the pulsed laser deposition technique. The room temperature ferromagnetism finds its origin in the holes introduced by the Bi doping and the p-p coupling between Bi and the host atoms. A sizeable magnetic moment is measured by means of x-ray magnetic circular dichroism at the O K-edge, probing directly the spin polarization of the O(2p) states. This result is in agreement with the theoretical predictions and inductive magnetometry measurements. Ab initio calculations of the electronic and magnetic structure of ZnBi_xO_1−x at various doping levels allow to trace the origin of the ferromagnetic character of this material. It appears, that the spin-orbit energy of the heavy ion Bi stabilizes the ferromagnetic phase. Thus, ZnBi_xO_1−x doped with a heavy non-ferromagnetic element, such as Bi, is a credible example of a candidate material for a new class of compounds for spintronics applications, based on the spin polarization of the p states.

We investigated the electrical properties of a GaN nanorod $p\text{-}n$ junction diode patterned on a $\mathrm{Si}{\mathrm{O}}_2$ substrate using e-beam lithography. The electron transport mechanisms were characterized by temperature-dependence and current-voltage measurements. At a low temperature, the current-voltage curves showed that the current slowly increased with a given voltage for the forward bias and hardly changed for the reverse bias, indicating the tunneling current dominates through the deep trap barrier. At a high temperature, however, the current-voltage curves exhibited strong temperature dependence suggesting that thermionic emission with an activation energy of $19.1\mathrm{meV}$ over a barrier dominated.