Center for Relativistic Laser Science

124th Summer Symposium of KCS-Physical Chemistry Division

The HgS Collidal Quantum Dots(CQDs) with Mid-IR intraband gap can be fascinating materials for IR photodevices and laser¹. Here, we reported the interesting exciton relaxation dynamics of Dodecanethiol-doped HgS CQD’s observed with femtosecond IR pump-probe experiments. With the variation of pump-power, we observed pump power-independent fast decaying dynamics (1.2 ± 0.1ps) which might be caused by Auger process in CQDs after biexciton generation. Slow decay process (>300 ps) were also measured and assigned as Phonon bottleneck process for CQDs with single exciton state. Moreover, the intermediate component(~20ps) is also appeared. To address the physical meaning of this component, we did the IR pump-probe experiments varying the ligands of CQD to check the effect of surface states and finally could assigned this intermediate as the surface component.

References

[1] Guyot-Sionnest, P., Shim, M., Matranga, C., & Hines, M. Intraband relaxation in CdSe quantum dots. Physical Review B, 60(4),R2181(1999)