Analysis of the relaxation process of electron-hole pairs in α -Al2O3 using transient absorption spectroscopy

摘要

Abstract We measured transient absorption in α-Al2O3 after pulsed electron beam irradiation to analyze the relaxation process of excited states. We used two measurement systems to obtain transient absorption in nanosecond and picosecond time scales. In the nanosecond time scale, we observed a band at 610 nm in addition to a shoulder at 420 nm. This observation is consistent with that in a previous paper, and these bands are attributed to Al interstitials according to the paper. The decay behavior of these bands was significantly different in the picosecond time scale. The difference in the decay kinetics strongly suggests that the band at 610 nm and the shoulder at 420 nm are attributed to two kinds of Al interstitials.