Ultraviolet light-emitting diodes based on ZnO/NiO heterojunctions were fabricated on commercially available $n^{+}\text{-GaN}$ /sapphire substrates using a radio frequency magnetron sputtering system. Near band edge emission of ZnO peaking at $\sim 370\text{nm}$ with a full-width at half maximum of $\sim 7\text{nm}$ was achieved at room temperature when the devices were under sufficient forward bias. With the help of an electron blocking $i{\text{-Mg}}_{1-x}{\text{Zn}}_x\text{O}\left(0<x<1\right)$ layer inserted between the ZnO and NiO layers, the emission intensity has been much enhanced and the threshold current drops down to $\sim 23$ from $\sim 70\text{mA}$ . The results were discussed in terms of the band diagrams of the heterojunctions.

$N\text{-ZnO}$ nanorods/$n$ -silicon heterojunction was fabricated by growth of ZnO nanorods on a $n$ -type silicon (111) wafer with a low-temperature aqueous solution method. Capacitance-voltage measurements revealed that after annealing at $900°\text{C}$ in ${\text{O}}_2$ ambient for 1 h, the heterojunction changed from abrupt $N\text{-ZnO}$ nanorods/$n$ -silicon to graded $P\text{-ZnO}/n$ -silicon junction. The annealed diode showed good photoresponse in both the ultraviolet and visible regions with responsivity around 0.3 and 0.5 A/W without bias. The photoresponses toward ultraviolet and visible light were enhanced when the diode was under reverse and forward bias, respectively. The results were discussed in terms of phosphorus diffusion process and the band diagrams of the heterojunctions in this work.

Novel, stable, and lead-free CsCuBr₂ halides were synthesized and utilized as efficient light emitters.

All inorganic, self-powered, narrowband, and rapid response p-NiO/n-ZnO nanowire (NW) ultraviolet (UV) photodetectors were fabricated and investigated with Al₂O₃ as an interface modification layer. Al₂O₃ films grown by atomic layer deposition can greatly suppress the surface defects on ZnO NWs and improve the p-NiO/n-ZnO NW interface. The photo-response of the photodetector in the 430–500 nm wavelength range was greatly inhibited and the full-width at half-maximum of the response spectrum was less than 30 nm. A large responsivity of 1.4 mA/W was achieved under a 380 nm UV irradiation (0.36 mW/cm²) at zero bias and the response time of the device was less than 0.04 s. Such a simple interface modification method might promote the developing of ZnO NW based narrowband photodetectors.

A ZnO/ZnMgO multiple-quantum-well ultraviolet (UV) random laser diode was fabricated on a commercially available n-type GaN wafer using a radio frequency magnetron sputtering system. The electroluminescence measurements revealed that the diode exhibited fairly pure UV random lasing centered at ~370 nm under sufficient forward bias at room temperature. The full-widths at half-maximum of the sharp lasing peaks are less than 0.4 nm. The device has a very low threshold current density of 4.7 A/cm² and extremely weak visible emission.