Abstract
Relaxation and diffusion processes of high-density excitons in layered-type semiconductor PbI 2 have been investigated through femtosecond transient grating and time-resolved luminescence measurements under two-photon absorption. We observed two luminescence bands at low temperature; one is due to an exciton–exciton collision process, while the other originates from localized excitonic states. By utilizing the transient grating spectroscopy, the lifetime and diffusion coefficient of the high-density excitons in PbI 2 are estimated to be 72 ps and 4.6 cm 2/s, respectively. The lifetime observed is almost equal to the values of the decay time of the luminescence due to the exciton–exciton collision process and the rise time of the luminescence due to the localized excitons. This strongly shows that the decay of the exciton–exciton collision process is dominated by the exciton trapping to the localized states arising from potential fluctuations due to imperfection of crystal.
Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
