Electrically pumped ultraviolet lasing in polygonal hollow microresonators: investigation on optical cavity effect

Electrically driven ultraviolet lasing was realized in two-dimensional ZnO nanowall networks from Au/MgO/n-ZnO/n-GaN/In structure, and whispering gallery type resonant modes are responsible for the lasing action. We present a comparative study on lasing action based on nanowall networks with different micro-hole sizes. The representative diode (Device II) with a moderate micro-hole size exhibits an ultralow threshold current density of 1.01 A/cm(2), and the lasing action can be sustained at a temperature up to similar to 413 K, showing a good temperature tolerance. Moreover, the corresponding characteristic temperature for Device II was derived as similar to 91.4 K. It can be qualitatively anticipated that this work will provide instructive guidelines for fabrication and development of high-performance ultraviolet laser diodes by using two-dimensional ZnO nanowall networks as the lasing gain media. (C) 2016 Optical Society of America