Figure 1

Schematic drawing of the exciton formation assisted by LO-phonon emission, the subsequent relaxation by acoustic-phonon (AC) emission, and the resulting zero-phonon line (ZPL) and phonon sideband (PSB).Reuse & Permissions

Figure 2

Photoluminescence spectra measured at 7 K. The excitation intensity is $1\mathrm{k}\mathrm{W}/{\mathrm{c}\mathrm{m}}^{\mathrm{2}}$.Reuse & Permissions

Figure 3

(a) Spectra of PSB measured at different positions with respect to the excitation-laser spot. The distances from the excitation spot to the detection spot are (from top to bottom) 0, 460, 920, and 1380 nm, respectively. The excitation-laser energy is 2.8611 eV, with an intensity of $1\mathrm{k}\mathrm{W}/{\mathrm{c}\mathrm{m}}^{\mathrm{2}}$. (b) Spatial profiles of the excitation-laser spot (circles), RRS (stars), HL (squares), and ZPL (down triangles). The spatial profile of one spectral component in the PSB, indicated as the arrow in (a), is also shown as the up triangles. The solid lines represent the corresponding Gaussian fits to the data. (c) HWHM of the spectral components in the PSB as function of the photon energy. The HWHMs are obtained by Gaussian fits of the spatial profiles of the selected components. The HWHMs of the ZPL (dashed line), RRS (dotted line), and laser spot (solid line) are also shown for comparison.Reuse & Permissions

Figure 4

Exciton coherence lengths (squares) deduced from the spatial profiles of the HL peaks for several exciton kinetic energies. The solid line is a guide for the eyes. Also shown is the calculated coherence length (dotted line) limited by acoustic-phonon scattering without considering the influence of disorder.Reuse & Permissions