Hanle effect and spin-dependent recombination at deep centers in GaAsN

The peculiarities of Hanle effect (i.e., the depolarization of edge photoluminescence in a transverse magnetic field) in semiconductors, brought about by spin-dependent recombination of free electrons with deep paramagnetic centers, have been investigated in GaAs(0.979)N(0.021) alloy at room temperature. The measured Hanle curve consists of narrow and wide parts with the widths at the half-height being similar to 100 and similar to 120000G. The difference between the widths by three orders of magnitude results from strongly differing spin lifetimes of bound and free electrons, T(sc) and T(s). Using g-factor values +2 and +1 for bound and free electrons, respectively, we have found that T(sc) approximate to 700 Ps and T(s) approximate to 2 ps. Thus obtained values of T(sc) and T(s) allow us to describe theoretically the experimental Hanle curve as well as its dependence on the pump intensity. (C) 2009 Elsevier B.V. All rights reserved.