Direct, spatially resolved observation of defect states with electromigration and degradation of single crystal SrTiO3

2020 ◽  
Vol 127 (9) ◽  
pp. 094105 ◽  
Author(s):  
Hantian Gao ◽  
Sulata Sahu ◽  
Clive A. Randall ◽  
Leonard J. Brillson
2019 ◽  
Vol 7 (42) ◽  
pp. 13156-13160 ◽  
Author(s):  
Svetlana Sirotinskaya ◽  
Christian Fettkenhauer ◽  
Daichi Okada ◽  
Yohei Yamamoto ◽  
Doru C. Lupascu ◽  
...  

Introducing a modal system approach for the analytical perovskite thin-film trap physics evaluation. Our study confirms existing models for trap formation in MAPI, substantiating different defect states in the grain boundary and bulk regions.


2018 ◽  
Vol 89 (1) ◽  
pp. 015106 ◽  
Author(s):  
M. S. Wallace ◽  
S. Haque ◽  
P. Neill ◽  
N. R. Pereira ◽  
R. Presura

2016 ◽  
Vol 25 (03) ◽  
pp. 1650037 ◽  
Author(s):  
A. Alexandar ◽  
P. Surendran ◽  
S. Sakthy Priya ◽  
A. Lakshmanan ◽  
P. Rameshkumar

Organic nonlinear optical (NLO) single crystal of L-tartaric acid–nicotinamide (LTN) has been grown by slow evaporation solution technique at a constant temperature of 40[Formula: see text]C. The grown crystals were subjected to various characterization techniques in order to examine their suitability for various applications. Powder X-ray diffraction (PXRD) analysis revealed that the compound is formed without any impurities. Functional groups and formation of the title compound were confirmed using FTIR analysis. Optical behavior of the material was examined using UV–Vis NIR spectrum analysis and the lower cut-off wavelength and optical band gap energy were calculated. Microhardness, dielectric and piezoelectric studies have been carried out at ambient conditions. Electronic properties such as valence electron plasma energy, Penn gap, Fermi energy and electronic polarizability were calculated by Clausius–Mossotti relation. Photoluminescence analysis was carried out to study the luminescence nature of the crystal and its defect states. In addition photoconductivity, etching studies and powder Kurtz and Perry second harmonic generation (SHG) test were carried out.


Nanomaterials ◽  
2021 ◽  
Vol 11 (11) ◽  
pp. 3057
Author(s):  
Ulrich Johannes Bahnmüller ◽  
Henning Kuper ◽  
Tobias Seewald ◽  
Yenal Yalҫinkaya ◽  
Jörg August Becker ◽  
...  

Hybrid perovskite materials are one of the most promising candidates for optoelectronic applications, e.g., solar cells and LEDs, which can be produced at low cost compared to established materials. Although this field of research has seen a huge upsurge in the past decade, there is a major lack in understanding the underlying processes, such as shape-property relationships and the role of defects. Our aerosol-assisted synthesis pathway offers the possibility to obtain methylammonium lead bromide (MAPbBr3) microcrystals from a liquid single source precursor. The differently shaped particles are aligned on several substrates, without using a directing agent or other additives. The obtained particles show good stability under dry conditions. This allows us to characterize these materials and their pure surfaces at the single-crystal level using time- and spatially resolved methods, without any influences of size-dependent effects. By optimizing the precursor for the aerosol process, we were able to eliminate any purification steps and use the materials as processed. In addition, we performed theoretical simulations to deepen the understanding of the underlying processes in the formation of the different crystal facets and their specific properties. The model system presented provides insights into the shape-related properties of MAPbBr3 single crystals and their directed but ligand-free synthesis.


Coatings ◽  
2020 ◽  
Vol 10 (3) ◽  
pp. 206
Author(s):  
Jinhee Park ◽  
You Seung Rim ◽  
Pradeep Senanayake ◽  
Jiechen Wu ◽  
Dwight Streit

The characterization of defect states in a hydrothermally grown single crystal of ZnO was performed using deep-level transient spectroscopy in the temperature range of 77–340 K. The native intrinsic defect energy level within the ZnO band gap occurred in the depletion region of ZnO Schottky barrier diodes. A major defect level was observed, with a thermal activation energy of 0.27 eV (E3) within the defect state distribution from 0.1 to 0.57 eV below the conduction band minimum. We confirmed the maximum defect concentration to be 3.66 × 1016 cm−3 at 0.27 eV (E3). As a result, we clearly confirmed the distribution of density of defect states in the ZnO band gap.


2019 ◽  
Vol 11 (44) ◽  
pp. 41551-41560 ◽  
Author(s):  
Mahshid Ahmadi ◽  
Liam Collins ◽  
Kate Higgins ◽  
Dohyung Kim ◽  
Eric Lukosi ◽  
...  

2003 ◽  
Vol 797 ◽  
Author(s):  
S. Richter ◽  
S. L. Schweizer ◽  
R. Hillebrand ◽  
C. Jamois ◽  
R. B. Wehrspohn ◽  
...  

ABSTRACTWe present and characterize hexagonal point defects in a two dimensional photonic crystal based on macroporous silicon. These point defects are prepatterned periodically, forming a superstructure within the photonic crystal after electrochemical etching. Spatially resolved, optical investigations related to morphological properties, like defect concentration and pore radius, are compared to bandstructure calculations. The confined defect states are identified and their interaction is evaluated quantitatively.


Author(s):  
J. B. Posthill ◽  
R. J. Graham ◽  
D. P. Malta ◽  
T. George ◽  
R. A. Rudder ◽  
...  

We have continued to investigate different diamond single crystal substrates to assess their suitability for the growth of homoepitaxial diamond. Surface topography and defect microstructure of the resulting films are two important qualifiers for the choice of a suitable substrate. Previously developed methods to prepare plan-view TEM samples from bulk diamond substrates and homoepitaxial films have been employed. This contribution describes some of our most recent observations of the surfaces andmicrostructure of natural and synthetic diamond single crystals and homoepitaxial diamond thin films using SEM and TEM - including spatially resolved cathodoluminescence (CL) results.Figs. 1 and 2 show TEM micrographs taken from a (100) natural type Ila diamond crystal and a (100) synthetic type lb diamond that have been ion milled to electron transparency. The mottled background contrast observed in both images which has been observed previously and is believed to result from the extended ion milling used to produce these thin foils.


1994 ◽  
Vol 332 ◽  
Author(s):  
David A. Muller ◽  
Yujiun Tzou ◽  
Rishi Raj ◽  
John Silcox

ABSTRACTThe interfacial structure of CVD diamond grown on silicon was studied using spatially resolved electron energy loss spectroscopy (EELS) in a UHV STEM with a subnanometer probe size. Both the plasmon and core excitations in the bulk appear to be localized on this scale. Spatial maps of the different bonding configurations of carbon were obtained by forming images from transmitted electrons that had undergone energy losses characteristic of threefold and fourfold coordinated carbon. Films grown on both prescratched silicon and intermediate amorphous carbon layers were examined. In the latter case, diamond nucleation on a narrow sp2 a-C occurred. For diamond grown directly on silicon, at some regions of the interface, threefold coordinated defect states smaller than 1 nm are observed on the diamond side of the interface while at other regions along the interface the presence of an intermediate 2nm thick SiC layer preserves the fourfold coordination of the carbon.


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