Crystallization Study of Evaporated a-Se Films by Means of DTA Technique

Abstract

Starting from the results obtained for the isothermal crystallization, the expressions are determined giving the transformation rate for a non‐isothermal regime (DTA). This model enables us to determine experimentally the apparent energies of the growth rate (E = 0.89 eV) and nucleation rate (U = 1.3 eV). It is also shown that a temperature range exists where the heterogeneous crystallization with cylindrical growth is preponderant and, for higher temperatures, the crystallization becomes homogeneous with crystallites of size greater than the film thickness.

Determination of thermodynamic parameters of the amorphous selenium films crystallization

“…I n previous papers 11, 21 we have studied the crystallization of amorphous selenium (a-Sej films evaporated on aluminium substrates. We have shown that in this case the nucleation is homogeneous; the number N of crystallites created per unit time and volume is given by [2] growth rate by v = vnl exp (-g;) H. ATMANI (4) and we have found for the apparent activation energy El = 0.95 eV and tiol = 6.5 x lo5 ni/s .…”

“…The study of the non-isothermal crystallization by differential thermal analysis (DTA) [2] has shown that the crystallization peaks obtained for different heating rates occixr in a narrow temperature range so that we may write…”