Phonon-assisted stimulated emission from single CdS nanoribbons at room temperature

We report room-temperature stimulated emission in single CdS nanoribbons obtained through Au-catalyzed physical evaporation route. These ribbons have single-crystal structures and uniform rectangular cross sections and grow along the [100] direction. The ribbons show good waveguide/cavity properties under local optical excitation. The stimulated emissions from the single ribbons were observed with both nanosecond and femtosecond laser pumpings. The results show that the CdS nanoribbons produce stimulated emission by bipolaronic excitons (two-longitudinal-optical phonon coupled free excitons) at room temperature.