Band Gap Extraction from Individual Two-Dimensional Perovskite Nanosheets Using Valence Electron Energy Loss Spectroscopy

2016 ◽  
Vol 120 (20) ◽  
pp. 11170-11179 ◽  
Author(s):  
Kulpreet S. Virdi ◽  
Yaron Kauffmann ◽  
Christian Ziegler ◽  
Pirmin Ganter ◽  
Peter Blaha ◽  
...  
Keyword(s):  
Energy Loss ◽  
Band Gap ◽  
Electron Energy ◽  
Electron Energy Loss Spectroscopy ◽  
Valence Electron ◽  
Two Dimensional ◽  
Electron Energy Loss ◽  
Band Gap Extraction

Insights into the Electronic Structure of Ceramics Through Quantitative Analysis of Valence Electron Energy-Loss Spectroscopy (VEELS)

1999 ◽  
Vol 5 (S2) ◽  
pp. 666-667
Author(s):  
Harald Müllejans ◽  
Roger H. French
Keyword(s):  
Electronic Structure ◽  
Energy Loss ◽  
Band Gap ◽  
Electron Energy ◽  
Electron Energy Loss Spectroscopy ◽  
Valence Electron ◽  
Metallic Materials ◽  
Loss Peak ◽  
Conduction Bands ◽  
Electron Energy Loss

The electronic structure of ceramics can be extracted quantitatively from the valence electron energy-loss spectroscopy (VEELS) of transitions between the valence and conduction bands. We obtained VEEL spectra of several ceramics (FIG. 1) with a VG HB501 dedicated STEM equipped with Gatan PEELS. Improved data acquisition and new methods of data analysis allowed us to treat the data fully quantitatively. The reliable and accurate removal of the zero loss peak was crucial because intensities at energy losses just above the band gap of the ceramic material have a large influence on the results. An asymmetric Pearson VII function was fitted into the zero loss peak up to an energy loss for which no transitions are expected (an energy smaller than the band gap of the ceramic) and then extrapolated to higher energies. This limits the analysis to non-metallic materials, exhibiting non-zero band gap energies. We are currently developing methods to perform the analysis on metallic materials, using ellipsometric data in the visible and extrapolate the energy-loss function to 0 eV and thereby remove the need for the no transition energy.

scholarly journals Band gap widening at random CIGS grain boundary detected by valence electron energy loss spectroscopy

2016 ◽  
Vol 109 (15) ◽  
pp. 153103 ◽  
Author(s):  
Debora Keller ◽  
Stephan Buecheler ◽  
Patrick Reinhard ◽  
Fabian Pianezzi ◽  
Benjamin Bissig ◽  
...  
Keyword(s):  
Grain Boundary ◽  
Energy Loss ◽  
Band Gap ◽  
Electron Energy ◽  
Electron Energy Loss Spectroscopy ◽  
Valence Electron ◽  
Electron Energy Loss

Quantifying the low-energy limit and spectral resolution in valence electron energy loss spectroscopy

2013 ◽  
Vol 124 ◽  
pp. 130-138 ◽  
Author(s):  
Jeffery A. Aguiar ◽  
Bryan W. Reed ◽  
Quentin M. Ramasse ◽  
Rolf Erni ◽  
Nigel D. Browning
Keyword(s):  
Energy Loss ◽  
Electron Energy ◽  
Spectral Resolution ◽  
Electron Energy Loss Spectroscopy ◽  
Valence Electron ◽  
Low Energy ◽  
Energy Limit ◽  
Electron Energy Loss

scholarly journals Chemical identification through two-dimensional electron energy-loss spectroscopy

2020 ◽  
Vol 6 (28) ◽  
pp. eabb4713
Author(s):  
Renwen Yu ◽  
F. Javier García de Abajo
Keyword(s):  
Energy Loss ◽  
Electron Energy ◽  
Electron Energy Loss Spectroscopy ◽  
Electronic Device ◽  
Theoretical Calculations ◽  
Chemical Species ◽  
High Sensitivity ◽  
Two Dimensional ◽  
Excitation Spectra ◽  
Electron Energy Loss

We explore a disruptive approach to nanoscale sensing by performing electron energy loss spectroscopy through the use of low-energy ballistic electrons that propagate on a two-dimensional semiconductor. In analogy to free-space electron microscopy, we show that the presence of analyte molecules in the vicinity of the semiconductor produces substantial energy losses in the electrons, which can be resolved by energy-selective electron injection and detection through actively controlled potential gates. The infrared excitation spectra of the molecules are thereby gathered in this electronic device, enabling the identification of chemical species with high sensitivity. Our realistic theoretical calculations demonstrate the superiority of this technique for molecular sensing, capable of performing spectral identification at the zeptomol level within a microscopic all-electrical device.

scholarly journals Characterization of InGaN/GaN quantum well growth using monochromated valence electron energy loss spectroscopy

2014 ◽  
Vol 115 (3) ◽  
pp. 034302 ◽  
Author(s):  
J. Palisaitis ◽  
A. Lundskog ◽  
U. Forsberg ◽  
E. Janzén ◽  
J. Birch ◽  
...  
Keyword(s):  
Quantum Well ◽  
Energy Loss ◽  
Electron Energy ◽  
Electron Energy Loss Spectroscopy ◽  
Valence Electron ◽  
Electron Energy Loss
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