CALCULATION OF ALLOY DISORDER INFLUENCE ON HOLE IONIZATION BEHAVIOR IN GA1-XALXSB COMPOUNDS

The calculation of the ionization probability and of the ionization co efficients of the holes of the spin split-off valence band in Ga1-xAlx Sb has been made for various compositions 0<x<0.08. This range allows us to obtain the situations in which the ratio of spin orbit splitting Delta to the energy gap E(g) decreases from 1.05 to 0.89. It is shown that if the alloy disorder is neglected, the hole ionization coeffici ent k(p) exhibits a continuous variation with Delta/E(g) (or x); if no t, k(p) is strongly increased and shows a maximum for x=0.02 in the co mposition range in which Delta greater than or equal to E(g) (Delta/E( g) =1.006). The comparison with experimental results is presented and allows an estimation of the mean free path of the holes; the strong in fluence of this parameter on the k(p) values is discussed.