EPR IDENTIFICATION OF THE TRIGONAL TI-GA(2-S(P) PAIR IN GAP())

EPR experiments on titanium-doped n- and p-type GaP are reported. In n -type Ga P: Ti co-doped with sulphur additional to the known isolated defects an angular dependent spectrum showing trigonal symmetry can be observed. The analysis suggests that the spectrum is caused by a dono r-acceptor nearest-neighbour pair defect [Ti(Ga)2+-S(P)]. The paramete rs of the spin-Hamiltonian are determined as follows: S = 1, g(paralle l-to) = g(perpendicular-to) = 1.95(1), Absolute value of D = 0.0670(5) cm-1. The concentration of the pair defect confirms that Coulomb attr action is responsible for its preferential formation. However, no EPR spectrum of a pair can be proved for p-type GaP: Ti co-doped with Zn, although the existence of such a pair is also most probable. The lack of the EPR spectrum could have spectroscopical reasons.