Modal gain and its diameter dependence in single-ZnO micro- and nanowires

Nanowires can successfully be used as building blocks for nanoscaled laser devices. Calculations predict an extremely large modal gain for nanowires made up of semiconductors such as GaN or ZnO. We determine experimentally the modal gain of single-ZnO nano- and microwires to approach 5000 cm−1 under particular size conditions. We demonstrate the distinct and sensitive dependence of the modal gain on the wire diameter and discuss optimizations for lasing of these wires.