Cutting-edge applications of SEM-CL

Zinc Oxide, Magnesium Oxide and other hybrid nanostructures
Cathodoluminescence (SEM-CL) provides analytical scientist consistent information about novel ZnO and other opto-electronic material nanocomposites such like nanodots, nanowires, self-assembled nanotetrapods, quantum dots, quantum well... Accessible information include growth defects localisation, crystallinity, interstitials, and excitonic band emission peaks and recombination pathways from the DUV to NIR.

Doped ZnO nanomaterials
Investigating the cristalline structure of doped Zinc Oxide  nanoparticles (ZnO:Al, ZnO:V, ZnO:Ca…) is crucial for research in photovoltaics (ZnO:Ca as a transparent electrode), environment (photocatalysts nanopowders ),  semi-conductors (sensors)… Our solution is flexible and combines Photoluminescence and Cathodoluminescence measurement on the same spectrometer setup; for a comprehensive characterization.

GaN crystal growth
The development of technology for light emitting diodes or other gallium nitride-based devices has dramatically improved the material quality.Gallium nitride (GaN) layers obtained by hetero-epitaxy on sapphire or silicon substrates by metal organic vapour phase epitaxy (MOVPE) have benefited from specific  growth techniques such as transitions from three to two dimensional growth or silicon nitride interlayers which have reduced the threading dislocation density tremendously. Cathodoluminescence reveals  dislocations at the boundary interface between the seed and the grown GaN crystal, providing an easy-to-use solution for optimization of the growth process, and a way of monitoring the stress in bulk GaN crystals.

Solar cells (thin film silicon solar cells, CIGS, CZTS, CdTe, Perovskites and hybrid solar cells),
SEM-CL is used to investigate the distribution of recombination centers in semiconductors, including extended defects (dislocations, grain boundaries), stress fields, and compositional fluctuations.
Hyperspectral CL imaging acquires a spectrum for each pixel on the image at high speed (typically 10 ms/pixel). This is achieved by synchronizing the scanning of the electron beam with the spectrum acquisition. CL observations can be performed at temperatures between 15 and 300 K with appropriate cold stage.

Geology Mineralogy

Geology Mineralogy
Characteristics of detrital zircon age populations along with regional geological data suggest accumulation in a convergent and/or collisional, metamorphism and possible subductions - Geochronology of collision process permits to identify unity in different era (Neoproterozoic, Paleozoic…). Zircon growth of metamorphic rims is related to magmatism, and other tectonothermal events.

photon-energy

Insulators for layered material semi-conductors (h-BN, BP, MoS2…)
SEM-CL is complementary  to Raman and PL spectroscopy to characterize  layered 2D materials  such like hexagonal-Boron Nitride (h-BN); Black Phosphorus (BP), Molybdenum disulfide (MoS2) which are intrinsically of atomic thickness. Thanks to the spatial resolution of the e-beam, one can easily map opto-electronic  and structural properties  of few layer materials with 10-20nm spatial resolution in X, Y and Z directions, even for large or tunable bandgap semi-conductors,  insulators, …

Low Temperature Normalized CL spectra of bulk h-BN and flakes (100, 60, 27, 20, 8 and 6L)
Sample courtesy of Saint-Gobain material
Data courtesy of L. Schué and J. Barjon, GeMAC University of Versailles / Saint Quentin en Yvelines from hal.archives-ouvertes.fr/hal-01252628

Cathodoluminescence Application Notes

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