Suppression of Randomness in Electrically Pumped Random Lasing from a ZnO Film-Based Light-Emitting Device on Silicon

We report on the suppressed randomness in electrically pumped random lasing (RL) from a light-emitting device (LED) based on a metal-insulator-semiconductor (MIS) structure of Au/SiO (x) (x < 2)/ZnO on a silicon substrate, by means of patterning the light-emitting ZnO polycrystalline film into a number of square blocks separated by streets that are filled with the SiO x insulator. It is found that the RL modes can be remarkably reduced by shrinking the blocks in the absence of interblock optical coupling. Meanwhile, with the imposition of interblock optical coupling by shrinking the streets, the RL modes can be further reduced, and more importantly, the strongest mode wavelength is stabilized around 380 nm, where the ZnO film exhibits the largest optical gain.