Abstract
Streak camera measurements of luminescence from ZnO single crystals as a function of temperature show that the spontaneous radiative lifetime of the “free exciton” band at 380nm is 440ps at room temperature, decreasing to 290ps at 85K. The donor-bound exciton lifetime is 50ps from 85K down to 16K, the lowest temperature we measured. This is significantly faster than is consistent with the dipole matrix element of any single atom transition scaled to the same wavelength. We discuss the oscillator strength of extended exciton states based on the theory of defect-bound excitons, and examine its limit for free excitons. In that regard, we ask what physically limits the coherent dipole size and how a material might be engineered for “giant” exciton oscillator strength. The phenomenon applies to single excitons, not just coherently produced multiple excitations.
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 callMore From: Nuclear Instruments and Methods in Physics Research Section A: Accelerators, Spectrometers, Detectors and Associated Equipment
Disclaimer: 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.
