Yuebiao Li

Crystallographically oriented Zn nanocrystals formed in ZnO by Mn+-implantation

The nanostructural characteristics of ZnO implanted with Mn+ to doses ranging from 1×1015to1×1017cm−2 are systematically studied for both as-implanted and postannealed cases. The detailed structural characterizations confirmed that the Mn+ implantation and postannealing result in (1) the formation of crystallographically orientated Zn nanocrystals in the ZnO matrix and (2) Mn atoms occupy the Zn sites in ZnO.

Infrared absorption spectroscopy on OH–Ni complex in hydrothermally grown ZnO

The microstructure and combination behavior of transitional metal Ni and hydrogen (H) in hydrothermally grown ZnO were investigated by infrared absorption spectroscopy. An infrared absorption peak at 2782.9 cm−1 was observed in ZnO crystal hydrogenated in H2 gas at 725 °C for 30 min. Isotope substitution experiments and polarized infrared absorption spectra revealed that this peak results from the stretch local vibrational mode of a single interstitial hydrogen bound to oxygen, with OH bond oriented at an angle of 108° to the c axis of ZnO. Different from the mode at 3577.3 cm−1 induced by the OH–Li complex in the same sample, the mode at 2782.9 cm−1 is ascribed to the OH–Ni complex related to a bond-centered hydrogen, which is sitting in the basal plane of the hexagonal lattice between the substitutional Ni at a Zn site and O. Moreover, this OH–Ni complex is thermally stable up to 500 °C.

The Raman and IR spectroscopy study on the transition metal in ZnO

The behavior of transition metals in ZnO has become an important topic for spintronics. As the fundamental property, the nano-structural characteristics of the transition metal implanted ZnO have been studied. It is clearly observed that in ZnO the Mn+ implantation and post-annealing result in (1) the formation of crystallographically orientated Zn nanocrystals within the ZnO matrix and (2) Mn atoms occupy the Zn sites in ZnO by Raman spectroscopy. Further annealing of the high-dose Mn-implanted ZnO promotes the formation of ZnMn2O4 compounds near the surface and a porous structure within the implanted region, which is revealed by the transmission electron microscopy, electron energy loss spectroscopy and energy dispersive X-ray spectroscopy. The microstructure of Ni in ZnO has been observed to form a OH-Ni complex by the infrared spectroscopy measurements. This OH-Ni complex is thermally stable up to 500 °C.

New Shallow Donors in High-purity Si

Two new hydrogenic shallow donors with binding energies of 38.32 and 40.09 meV are observed, in addition to phosphorus (P) and antimony (Sb) donors, in n-type high-purity silicon crystals by means of high-resolution photothermal ionization spectroscopy.