J. L. Lyons, A. Janotti , and C. G. Van de Walle, Materials Department, UCSB

1. IRG-2 NSF-DMR 0520415 New insights in p-type conductivity of ZnO J. L. Lyons, A. Janotti, and C. G. Van de Walle, Materials Department, UCSB Zinc oxide (ZnO) has been intensively pursued as an optoelectronic material, in hopes of developing it into a wide-band-gap light emitter that would compete with GaN. Establishing p-type doping has been most challenging. Nitrogen has been regarded as the most promising acceptor, but convincing demonstrations of p-type doping have been lacking. New light has now been shed on this puzzling state of affairs. Professor Van de Walle’s Computational Materials group has performed cutting-edge first-principles calculations that show nitrogen acceptors to have an ionization energy of 1.3 eVmuch too large to enable p-type doping. They also explained why the behavior of nitrogen has been misinterpreted in so many of the previous investigations. Does this mean that all hope for p-type ZnO has to be abandoned? Substitutional acceptors (including Li, N, P, As, or Sb) will not yield p-type conductivity. The computations show, however, that interstitial doping (specifically using fluorine) still looks promising,