Integrating electron and near-field optics: dual vision for the nanoworld

Abstract

Abstract:The integration of near-field scanning optical microscopy (NSOM) with the imaging and localized excitation capabilities of electrons in a scanning electron microscope (SEM) offers new capabilities for the observation of highly resolved transport phenomena in the areas of electronic and optical materials characterization, semiconductor nanodevices, plasmonics and integrated nanophotonics. While combined capabilities for atomic force microscopy (AFM) and SEM are of obvious interest to provide localized surface topography in concert with the ease and large spatial dynamic range of SEM and dual beam imaging (e.g., in-situ AFM following focused ion beam modification), integration with near-field optical imaging capability can also provide access to localized transport phenomena beyond the reach of far-field systems. In particular, the flexibility that is achieved with the capability for independent, high resolution placement of an electron source, providing localized excitation in the form of free carriers, photons or plasmons, with scanning of the optical collecting tip allows for unique types of "dual-probe" experiments that directly image energy transfer. We review integrated near-field and electron optics systems to date, highlight applications in a variety of fields and suggest future directions.

Heterogeneous Charge Carrier Dynamics in Organic–Inorganic Hybrid Materials: Nanoscale Lateral and Depth-Dependent Variation of Recombination Rates in Methylammonium Lead Halide Perovskite Thin Films

“…24,29−32 As with electron-beaminduced current (EBIC) measurements 16,33 and various scanning probe force approaches, 34−36 CL microscopy has also enabled the spatial resolution of carrier transport through integration of electron and near-field optics. 37,38 In contrast to other optical characterization like optical microscopy and steady state or time-resolved PL, the lateral and axial resolution of CL microscopy depends only on the extent of electron scattering within the sample. It thus provides information truly on the nanoscale in all three dimensions.…”

Cross-Sectional Transport Imaging in a Multijunction Solar Cell

“…The AFM/NSOM is mounted inside an FEI Inspect 50 scanning electron microscope. A detailed description of the integrated system for nearfield transport imaging has been previously published [13], [14]. We excite with the electron beam at individual fixed points in the GaInAs (green circle) and the GaInP (red circle) layers (as indicated in Fig.…”

Carrier-Transport Study of Gallium Arsenide Hillock Defects

“…With the TI technique, one can directly visualize the combined influences of diffusion, drift, surface recombination, and photon recycling on energy transport as a result of localized carrier generation (Haegel et al, 2009; Baird et al, 2011; Blaine et al, 2012; Haegel, 2013; Little et al, 2013). In a TI measurement, the electron beam (e-beam) of an SEM is either fixed at a spot or scans along a line, generating charge carriers in steady-state conditions.…”

“…The luminescence is detected by the probe of a near-field scanning optical microscope (NSOM) scanning over the surface of the sample. NSOM can have a high-spatial resolution that exceeds the diffraction limit, allowing direct mapping of the carrier-transport process in the vicinity of individual defects, single interfaces, or grain boundaries (Haegel, 2013; Xiao et al, 2017).…”