Analysis of V defects in GaN-based light emitting diodes by scanning transmission electron microscopy and electron beam induced current

2008 ◽  
Vol 92 (24) ◽  
pp. 242103 ◽  
Author(s):  
C. L. Progl ◽  
C. M. Parish ◽  
J. P. Vitarelli ◽  
P. E. Russell
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Electron Beam ◽  
Scanning Transmission Electron Microscopy ◽  
Light Emitting Diodes ◽  
Induced Current ◽  
Light Emitting ◽  
Transmission Electron ◽  
Scanning Transmission ◽  
Electron Beam Induced Current

scholarly journals Identification of interstratified mica and pyrophyllite monolayers within chlorite using advanced scanning/transmission electron microscopy

2019 ◽  
Vol 104 (10) ◽  
pp. 1436-1443
Author(s):  
Guanyu Wang ◽  
Hejing Wang ◽  
Jianguo Wen
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Electron Beam ◽  
Clay Minerals ◽  
Scanning Transmission Electron Microscopy ◽  
Dark Field ◽  
Chemical Compositions ◽  
Scanning Transmission Electron ◽  
Transmission Electron ◽  
Scanning Transmission

Abstract Interstratified clay minerals reflect the weathering degree and record climatic conditions and the pedogenic processes in the soil. It is hard to distinguish a few layers of interstratified clay minerals from the chlorite matrix, due to their similar two-dimensional tetrahedral-octahedral-tetrahedral (TOT) structure and electron-beam sensitive nature during transmission electron microscopy (TEM) imaging. Here, we used multiple advanced TEM techniques including low-dose high-resolution TEM (HRTEM), high-angle annular dark-field scanning transmission electron microscopy (HAADF-STEM) imaging combined with energy-dispersive spectroscopic (EDS) mapping to study interstratified layers in a chlo-rite sample from Changping, Beijing, China. We demonstrated an interstratified mica or pyrophyllite monolayer could be well distinguished from the chlorite matrix by projected atomic structures, lattice spacings, and chemical compositions with advanced TEM techniques. Further investigation showed two different transformation mechanisms from mica or pyrophyllite to chlorite: either a 4 Å increase or decrease in the lattice spacing. This characterization approach can be extended to the studies of other electron-beam sensitive minerals.

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