Electrically pumped ZnO film ultraviolet random lasers on silicon substrate

The electrically pumped ultraviolet (UV) random lasing in $c$ -axis oriented ZnO polycrystalline films has been demonstrated. For this demonstration, a metal-oxide-semiconductor structure of $\mathrm{Au}∕\mathrm{Si}{\mathrm{O}}_x(x<2)∕\mathrm{Zn}\mathrm{O}$ film was fabricated on a silicon substrate. With ever-higher forward bias where the negative voltage was connected to the silicon substrate, the UV electroluminescence from such a ZnO-based device transformed from the spontaneous emission to the random lasing in the ZnO film. It is believed that the recurrent scattering and interference of the enough strong electroluminescent UV light in the in-plane random cavities formed in the ZnO film leads to electrically pumped UV random lasing.