Experimental and modeling study of charge carriers release from traps by interaction with molecular vibrations in silicon organic polymers

Fine structure of thermoluminescence assisted by molecular vibrations in disordered organic semiconductors

“…The energy and temperature dependence of P(E, T) is smoother function of the energy and temperature than the dependence of the factor exp(−|E|/κT) on these parameters. Also, the structures observed in the works [8][9][10][11] and studied in the present work manifest themselves in a narrow range of temperatures, at which the value of P(E, T) changes insignificantly. The value P(E, T) will be considered as a constant parameter of the system when performing concrete calculations.…”

“…Also because α mode has larger value of carrier-vibration interaction than another molecular vibration modes we may assume, that g 2 α > g 2 α . Constant g 2 α , at which fine structures were observed in some polymers in the work [11] had the minimal value of order 0. Let us consider the contribution of joint absorbtion of the molecular vibration of α type and low-frequency vibration under carrier transition to conductivity region.…”

“…In our previous works [8][9][10], we studied the influence of this interaction on the thermoluminescence in the first order of the perturbation theory, in which the interaction was taken into account in a linear expansion with respect to the displacements of nuclei. In the work [11] we applied the mechanism of the resonance energy transfer from the optical vibration to the carrier, which jump from one molecule to another. Such Forster-Dexter formalism was used by Hopfield for the consideration charge transitions [30].…”

“…The fine discrete structure on the thermoluminescence curve and the appearance of fictitious activation energies, when the fractional method was applied in the thermoluminescence study, were observed on different samples, for various substrates, and for several polymers poly(methylphenylsilane), poly(di-n-penthylsilane), poly(din-phenylsilane), poly(di-n-heptylsilane)) [8][9][10][11]. Si-Si vibrations with the energies of quanta 0.0462 eV and 0.061 eV in poly (di-n-hexylsilane) are examples of the vibrations, which give the structures on the thermoluminescence curve, they are observed under an application of the fractional thermoluminescece method [8][9][10][11] and are seen in Raman spectra [6]. The illustrative view is given in figure 2 for the vibration of poly(di − n − hexylsilane) molecule with the energy of quantum 0.0462 eV [12].…”

“…However more important is the fact that the existence of the considered phenomenon requires caution from the researcher in the interpretation of results concerning the trap levels obtained by the thermoluminescence methods. Really, according to the conclusions of the papers [8][9][10][11] the obtained activation energy may be rather the energy of a quantum of molecular vibrations.…”