Displacement Thresholds in ZnO

Residual Native Shallow Donor in ZnO

“…Since very little damage is seen for E , 1.6 MeV, the implication is that E th . [14], N in GaN (11 eV) [15], Si (13 eV) [16], and even C in diamond (80 eV) [17]. However, as we shall show later, effective values of E d can be much higher if the stable defects are only those which involve multiple atomic displacements, along a chain of atoms.…”

“…However, there should also be O-sublattice defects created at 2 MeV, as found by Smith and Vehse [19], using EPR experiments. Moreover, Locker and Meese [17] have found a threshold for carrier removal at 0.31 MeV, but it appears only after first irradiating their sample at .0.90 MeV. They argue that the 0.31 MeV threshold is due to O displacement, and that the one at 0.90 MeV is due to Zn displacement.…”

“…(1), E d Х 138 198 eV, which is much too high. In fact, Van Vechten has calculated E d ͑Zn͒ Х 18.5 eV and E d ͑O͒ Х 41.4 eV from a thermodynamic model [21], and Locker and Meese have estimated E d ͑Zn͒ E d ͑O͒ Х 57 eV from their experiments [17]. We believe that the resolution to this problem lies in the idea of multiple displacements along a chain of atoms.…”

Efficient Auger Charge-Transfer Processes in ZnO

“…Furthermore, from our studies performed with variable irradiation energies, the defect is formed only when the energy is above a threshold of around 0.8 MeV. This threshold is required to displace a Zn atom [23,44] but will also affect the O sublattice. Thus, the NBX formation involves a defect in either the Zn or O sublattice.…”

Mixed Zn and O substitution of Co and Mn in ZnO

“…Since these channeling and blocking effects strongly depend on the initial position of the emitted particles, they result in emission patterns that are characteristic of the lattice site(s) occupied by the probe atoms. The EC technique is ideal to study the lattice location of transition metals in semiconductors, as 24 and is therefore sufficiently high to re-implant the 61 Co atoms, ensuring that they do not inherit the 61 Fe lattice site. The 61 Mn ( 56 Mn) implantations were performed under a tilt angle of 17 • with respect to the surface normal in order to minimize ion channeling, with an energy of 60 keV (50 keV) and a fluence of 2×10 13 cm −2 , resulting in a peak concentration of 6×10 18 cm −3 (7×10 18 cm −3 ) at a projected range R p of 278Å (246Å) with a 125Å (115Å) straggling, estimated using the MARLOWE code.…”