Full text loading...
(a) Experimental setup. (b) The exciton model with spin-flip and decay rates defined. and denote the bright and dark exciton state, respectively, while is the crystal ground state. “rad” and “nrad” denote radiative and nonradiative decay channels. (c) Time-gated spectra. The early-time spectra are detected for and shown for 294 K (red circles) and 16 K (magenta squares). The late-time spectra are detected for and shown for 294 K (green diamonds) and 16 K (blue triangles). (d) The shift in peak center position of the early-time (blue squares) and late-time (red circles) spectra vs temperature. The black line denotes bandgap energy shift of bulk silicon.
Decay curves for temperatures 294 K (red), 100 K (green), 60 K (blue), and 16 K (black). The vertical axis is the same for all curves in [(a) and (b)]. (a) The initial fast thermalization of fluorescence. (b) The long-time decay curves. The red dashed line denotes the level of dark counts. (c) The 16 K decay curve normalized to the black line of panel (a). The blue line is a biexponential fit. (d) As panel (c) but with the 294 K data. The blue line is a single-exponential fit.
(a) The measured value of vs temperature. The vertical axis is normalized to the 16 K data point. (b) The measured ratio, , vs temperature. In panels [(a) and (b)] the red curve follows the model of Eq. (4) with and . (c) The characteristic decay time of the exciton levels vs temperature. (d) The characteristic time of the bright/dark-exciton state thermalization vs temperature.
Article metrics loading...