Photoabsorption Imaging at Nanometer Scales Using Secondary Electron Analysis

Abstract

Optical imaging with nanometer resolution offers fundamental insights into light–matter interactions. Traditional optical techniques are diffraction limited with a spatial resolution >100 nm. Optical super-resolution and cathodoluminescence techniques have higher spatial resolutions, but these approaches require the sample to fluoresce, which many materials lack. Here, we introduce photoabsorption microscopy using electron analysis, which involves spectrally specific photoabsorption that is locally probed using a scanning electron microscope, whereby a photoabsorption-induced surface photovoltage modulates the secondary electron emission. We demonstrate spectrally specific photoabsorption imaging with sub-20 nm spatial resolution using silicon, germanium, and gold nanoparticles. Theoretical analysis and Monte Carlo simulations are used to explain the basic trends of the photoabsorption-induced secondary electron signal. Based on our current experiments and this analysis, we expect that the spatial resolution can be further improved to a few nanometers, thereby offering a general approach for nanometer-scale optical spectroscopic imaging and material characterization.

Recent Progress in the Correlative Structured Illumination Microscopy

“…Electron microscopes, which easily attain nanometer and sub-nanometer resolutions, can image more delicate biological structures. Recent developments of SRM have correlated it with other SRM techniques and electron microscopy methods, achieving good results [159][160][161]. Hence, future significant advancements could be achieved by the correlation of SIM-STORM and electron microscopy for multicolor imaging.…”

The energetic and physical concept of gold nanorod-dependent fluorescence in cancer treatment and development of new photonic compounds|review

“…The (GNRs) contribute to enhanced optical imaging because of their strong absorption and scattering properties, while the silica shell can provide stability and biocompatibility for targeted imaging approaches. 13,[17][18][19] In summary, combining (GNR) and QDs offers a versatile hybrid system with enhanced optical features and potential imaging, sensing, and theragnostic uses. The integration of the unique plasmonic feature of (GNR) with the tunable emission feature of QDs provides opportunities for advanced imaging, sensitive detection, and multifunctional platforms for biomedical uses 17,20,21 and colloidal (G) nanoparticles, including (GNR), have found diverse uses in various elds.…”

“…13,[17][18][19] In summary, combining (GNR) and QDs offers a versatile hybrid system with enhanced optical features and potential imaging, sensing, and theragnostic uses. The integration of the unique plasmonic feature of (GNR) with the tunable emission feature of QDs provides opportunities for advanced imaging, sensitive detection, and multifunctional platforms for biomedical uses 17,20,21 and colloidal (G) nanoparticles, including (GNR), have found diverse uses in various elds. Their distinct optical feature makes them valuable in biomedical imaging, where they can play as contrast agents for techniques like dark-eld microscopy, electron microscopy, or surface-enhanced Raman spectroscopy (SERS).…”

Quantum Materials Manufacturing

“…[ 11 ] Moreover, improvements in advanced scanning electron microscopy (SEM), including photoabsorption microscopy using electron analysis (PAMELA), can transform commercial SEM instruments into sub‐20 nm imaging systems. [ 12 ] Scanning probe techniques that allow for quantifiable and nondestructive evaluation will continue to become more important as important feature sizes of quantum devices approach 10 nm and below. Nonlinear dark‐field imaging [ 13 ] coupled with Kelvin probe force microscopy and tip‐enhanced optical techniques [ 14 ] may become viable techniques to screen quantum phenomena (such as those depicted in Figure 2b–g) including photoluminescence at grain boundaries and point defects, domain orientation, and localized plasmons.…”