Delocalized Random Lasing in ZnS Nanowires Via Mie Scattering

High Resolution Image Download MS PowerPoint Slide Ultraviolet (UV) light sources with a low power consumption are crucial for advancing integrated optoelectronics. ZnS, a wide-band-gap semiconductor with a large exciton binding energy, offers unique advantages for UV applications. However, realizing random lasing based on Mie scattering in ZnS nanowires (NWs) remains a great challenge due to material absorption loss and insufficient optical feedback. In this article, high quality ZnS NWs arrays were fabricated through an electric-field assisted high temperature sintering technique, and the random cavity was optimized by strengthening the spatial density of the randomly oriented NWs. The dominant lasing mechanism arises from free exciton B recombination, exhibiting superior optical performance with a net optical modal gain of 62 cm –1 and a high characteristic temperature of 200 K. Crucially, the room temperature lasing threshold achieves an exceptional low value of 4.87 μJ/cm 2 (0.3 mW/cm 2 ), which is 5 orders of magnitude lower compared to previous results (45.3 W/cm 2 ), marking a significant breakthrough in excitonic laser technology. Moreover, leveraging the low spatial coherence of these ZnS random lasers, speckle-free imaging and anticounterfeiting applications have been demonstrated. This research not only quantifies the key operational parameters and significantly reduces the lasing threshold but also expands the potential applications for ZnS NW-based random lasers.