Premium
Characterization of the annealed (0001) surface of sapphire (α‐al 2 o 3 ) and interaction with silver by reflection electron microscopy and scanning reflection electron microscopy
Author(s) -
Ndubuisi Godfrey C.,
Liu J.,
Cowley J. M.
Publication year - 1992
Publication title -
microscopy research and technique
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.536
H-Index - 118
eISSN - 1097-0029
pISSN - 1059-910X
DOI - 10.1002/jemt.1070200413
Subject(s) - reflection high energy electron diffraction , sapphire , electron diffraction , scanning electron microscope , vicinal , annealing (glass) , materials science , electron microscope , reflection (computer programming) , single crystal , crystallography , microscopy , optics , diffraction , chemistry , physics , metallurgy , laser , organic chemistry , computer science , composite material , programming language
Annealed (0001) surfaces of single‐crystal sapphire (α‐Al 2 O 3 ) rod have been studied in the electron microscope using reflection electron microscopy (REM), scanning reflection electron microscopy (SREM), and reflection high energy electron diffraction (RHEED). Annealed surfaces of (0001) sapphire are vicinal and characterized by close‐packed (0001)‐oriented terraces separated by faceted multiple‐height steps, with edges parallel to energetically preferred low‐index directions (<101―0> and <112―0>). These structural features are not seen on cleaved surfaces or polished surfaces treated at temperatures < 1,250°C. Oxygen‐annealing produces clean surfaces which prove useful for investigating the interaction of deposited metals with the (0001) sapphire. Both REM and SREM (with microdiffraction spots) techniques have been used to observe fine structure of flat Ag islands on the scale of 1—100 nm on the (0001)‐oriented terraces as well as aggregations at the steps. A preliminary result on interaction with Cu is also included.