IMPACT IONIZATION IN GA1-XALXSB

We have measured impact ionization rates in Ga1-xAlxSb at x=0 and 0.08. For these Al contents, the ratio values of the spin-orbit splitting energy-DELTA to the energy gap E(g) are, respectively, greater and lower than unity. We have determined that the ratio of the ionization coefficients k(p)/k(n) is greater than unity for both compositions and that it is much lower (k(p)/k(n) almost-equal-to 2) than the value (> 10) determined on our layers for x=0.04. Multiplication noise measurements confirm these results. The comparison to other published data show that the ionization in these antimonide compounds is not yet elucidated.