Vibrational spectroscopy of OH-deep acceptor complexes in Ga₂O₃

Ga₂O₃ is doped with Fe to make it semi-insulating [1].  Other deep acceptors such as Mg also give rise to semi-insulating behavior [2].  The introduction of H (D) into Ga₂O₃ doped with Fe or Mg gives rise to O-H (O-D)vibrational lines near 3490 (2585) cm^-1 for both dopants [2,3].  Because Fe is frequently an unintentional contaminant in Ga₂O₃, we have performed additional experiments to investigate whether separate OH-deep acceptor complexes that contain Fe and Mg do indeed exist.  We have studied deep-acceptor doped samples with SIMS to determine the concentrations of Fe and Mg and have also probed the polarization properties, temperature dependences, and annealing stabilities of the OD-deep acceptor complexes for Fe and Mg doped samples.  Our results support the formation of distinct OD-Fe and OD-Mg complexes with very similar vibrational properties.