A PROCEDURE FOR CALCULATION OF THE DENSITY-OF-STATES OF WIDE-GAP SEMICONDUCTORS AND DIELECTRICS BY MEANS OF THE RECURSION METHOD

The recursion method allows to calculate the density of states for ele ctrons in solids from a continued fraction. Since only a finite number of coefficients can be computed, the truncation of the continued frac tion requires a procedure to approximate the effect of the uncalculate d coefficients. Different procedures have been propounded. When they a re applied to crystals having a wide gap this often shows up as a. min imum of the density of states, which renders the method unappropiate t o find the width of a gap and the energy of impurities and defects rel ative to the band edges. In this paper a procedure based on the method due to Nex [9] to find the integrated density of states is reported t hat yields better results than the usual ways of concluding the contin ued fraction.