Absorption spectra of at different temperatures ranging from .
Plots as a function of the photon energy.
The absorption coefficient spectrum for representative temperatures at . Experimental data are shown by the continuous line, whereas the theoretical fit to Eq. (2) is shown by the dashed-dotted line. Theoretical contributions to the spectrum of free and continuous excitons are indicated by dotted and dashed lines, respectively.
Temperature dependence of the direct gap of . The experimental results have been determined by extrapolation of the vs dependences (circles) and on the base of the Elliot’s model (triangles). The dotted line, the dashed line, and the dashed-dotted line are the calculated dependences according to the thermodynamic model, the Einstein model, and the Pässler model, respectively.
Logarithmic variation of the absorption coefficient with photon energy at several temperatures between 10 and , just below the fundamental absorption edge.
Temperature dependence of the steepness parameter (circles) and the Urbach tail width (triangles). The dotted line and the dashed line are the calculated dependences according to Eqs. (12) and (13), respectively.
Values of parameters , , , , , and obtained by fitting experimental data of absorption coefficient spectrum at different temperatures in the range of to Eq. (2). The errors in these parameters are given in parentheses.
Values of the adjustable parameters , , and , obtained by fitting Eqs. (3), (4), and (7), respectively, to the data of , estimated on the base of the linear extrapolation method (LEM) and the Elliot’s model. Errors are given in parentheses.
Article metrics loading...
Full text loading...