Zhili Yang, Matthew Pelton, Igor Fedin, Dmitri V. Talapin, and Edo Waks
Nature Communications, Vol. 8, Page 143 (2017)
Abstract: Colloidal semiconductor nanocrystals have emerged as promising active materials for solution-processable opto-electronic and light-emitting devices. In particular, the development of nanocrystal lasers is currently experiencing rapid progress. However, these lasers require large pump powers, and realizing an efficient low-power nanocrystal laser has remained a difficult challenge. Here we demonstrate a nanolaser using colloidal nanocrystals that exhibits a threshold input power of less than 1 mW, the lowest reported threshold for any laser using colloidal emitters. We use CdSe/CdS core-shell nanoplatelets, which are efficient nanocrystal emitters with the electronic structure of quantum wells, coupled to a photonic-crystal nanobeam cavity that attains high coupling efficiencies. The device achieves stable continuous-wave lasing at room temperature, which is essential for many photonic and opto-electronic applications. Our results show that colloidal nanocrystals are suitable for compact and efficient opto-electronic devices based on versatile and inexpensive solution-processable materials.