Shallow versus deep hydrogen states in ZnO and HgO

The muonium states mimicking interstitial hydrogen in ZnO and HgO are compared. Whereas in ZnO a theoretically predicted shallow donor state is confirmed, in HgO we find a considerably deeper state. The respective ionization temperatures are around 40 K and 150 K and the donor ionization energies are 19±1 and 136±3 meV, deduced from the temperature dependence of the µSR (muon spin-rotation) signal amplitudes. The µSR spectra provide a comprehensive characterization of the undissociated paramagnetic states: the hyperfine parameters, which measure the electron spin density on and near the muon, differ by a factor of ~30. These define a hydrogenic radius of 1.1 nm in ZnO but indicate a much more compact electronic wavefunction in HgO, more akin to those of Mu* and the AA9 centre in Si. These data should largely carry over to hydrogen as a guide to its electrical activity in these materials.

[1]  V. Walle,et al.  Hydrogen as a cause of doping in zinc oxide , 2000 .

[2]  K. Crowe,et al.  ANOMALOUS u+ PRECESSION IN SILICON , 1973 .

[3]  A. Stoneham,et al.  Studies of hydrogen in semiconductors using the positive muon as a proton analogue , 1995, Philosophical Transactions of the Royal Society of London. Series A: Physical and Engineering Sciences.

[4]  B. Hitti,et al.  Dynamics of negative muonium in n-type silicon , 1999 .

[5]  Luke,et al.  29Si hyperfine structure of anomalous muonium in silicon: Proof of the bond-centered model. , 1988, Physical review letters.

[6]  Chow,et al.  Muon-spin-resonance study of muonium dynamics in Si and its relevance to hydrogen. , 1995, Physical review. B, Condensed matter.

[7]  K. B. Nielsen,et al.  BOND-CENTERED HYDROGEN IN SILICON STUDIED BY IN SITU DEEP-LEVEL TRANSIENT SPECTROSCOPY , 1999 .

[8]  Holm,et al.  Deep state of hydrogen in crystalline silicon: Evidence for metastability. , 1991, Physical review letters.

[9]  T. A. Claxton,et al.  Vibrationally averaged spin densities on muons and protons in the hydroxyl and ethyl radicals , 1991 .

[10]  R. Lichti.  Muonium dynamics in semiconductors , 1995, Philosophical Transactions of the Royal Society of London. Series A: Physical and Engineering Sciences.

[11]  D. G. Thomas,et al.  Hydrogen as a Donor in Zinc Oxide , 1956, Halbleiter und Phosphore.

[12]  M. Symons,et al.  Molecular radical models for the muonium centres in solids , 1986 .

[13]  J. Krauser,et al.  Novel Muonium State in CdS , 1999 .

[14]  Johnson,et al.  Inverted order of acceptor and donor levels of monatomic hydrogen in silicon. , 1994, Physical review letters.

[15]  Estreicher.  Equilibrium sites and electronic structure of interstitial hydrogen in Si. , 1987, Physical review. B, Condensed matter.

[16]  R. Jones,et al.  Hydrogen and muonium in silicon , 1991 .

[17]  Pantelides,et al.  Theory of hydrogen diffusion and reactions in crystalline silicon. , 1989, Physical review letters.

[18]  B. Patterson.  Muonium states in semiconductors , 1988 .

[19]  Snyder,et al.  State and motion of hydrogen in crystalline silicon. , 1988, Physical review. B, Condensed matter.

[20]  S. Irvine,et al.  Experimental confirmation of the predicted shallow donor hydrogen state in zinc oxide. , 2001, Physical review letters.

[21]  A. R. Hutson.  Hall Effect Studies of Doped Zinc Oxide Single Crystals , 1957 .