2014 | 2013 | 2012 | 2011 | 2010 | 2009 | 2008 | 2007 | 2006 | 2005 | 2004 | 2003 | 2002 | 2001 | 2000 | 1999 | 1998 | 1997 | 1996 | 1995 | 1994 | 1993 | 1992 | 1991 | 1990 | 1989 | 1988 | 1987 | 1986 | 1985 | 1984 | 1983 | 1982 | 1981 | 1980 | 1979 | 1978 | 1977 | 1976 | 1975 | 1974 | 1973 | 1972 | 1971 | 1970 | 1969 | 1968 | 1967 | 1966 | 1965 | 1964 | 1963 | 1962 | 1961 | 500 | 76 | 0
Oxide muonics I: Modelling the electrical activity of hydrogen in semiconducting oxides
Authors: S.F.J Cox, J.S. Lord, S.P. Cottrell, J.M. Gil, H.V. Alberto, A. Keren, D. Prabhakaran, R. Scheuermann, and A. Stoykov
Ref.: J. Phys.: Condens. Matter 18, 1061-1078 (2006)
Abstract: A shallow-to-deep instability of hydrogen defect centres in narrow-gap oxide semiconductors is revealed by a Study of the electronic structure and electrical activity of their muonium counterparts, a methodology that we term ´muonics´. In CdO, Ag(2)O and Cu(2)O, paramagnetic muonium centres show varying degrees of delocalization of the Singly Occupied orbital, their hyperfine constants spanning 4 orders Of Magnitude. PbO and RuO(2), on the other hand, show only electronically diamagnetic muon states, mimicking those of interstitial protons. Muonium in CdO shows shallow-donor behaviour, dissociating between 50 and 150 K; the effective ionization energy of 0.1 eV is at some variance with the effective-mass model but illustrates the possibility of hydrogen doping inducing n-type conductivity as in the wider-gap oxide, ZnO. For Ag(2)O, the principal donor level is deeper (0.25 eV) but ionization is nonetheless complete by room temperature. Striking examples of level-crossing and RF resonance spectroscopy reveal a more complex interplay of several metastable states in this case. In Cu(2)O, muonium has quasi-atomic character and is stable to 600 K, although the electron orbital is Substantially more delocalized than in the trapped-atom states known in certain wide-gap dielectric oxides. Its eventual disappearance towards 900 K, with an effective ionization energy of 1 eV, defines an electrically active level near mid-gap in this material.
