MAJOR INSTRUMENTATION FOR TRANSMISSION ELECTRON MICROSCOPY

System Analytical Technique Typical Applications Lateral Resolution Special Features

FEI F20 (UT)

Phillips CM30 Transmission electron 

microscopy

Structural and compositional 

analysis and lattice imaging

0.23 nm High-resolution, EDS

Field-emission scanning 

transmission electron 

microscopy

Structural, electronic, and 

compositional analysis; elemental 

mapping; lattice imaging

0.19 nm for HRTEM;

0.14 nm for Z-contrast 

STEM

High-resolution, Z-contrast, EDS, 

EELS,Energy filtering, Fieldemission electron source

FEI NOVA 200 Field-emission scanning 

electron (SEM) and ion 

(SIM) microscopy

1.1 nm @ 15 kV for 

SEM

7 nm for SIM

Preparation of TEM and SEM 

samples. Fabrication of nanostructures 

THERMO EDS

FIB etch and deposition

High-resolution SEM

We combine two complementary areas of analytical microscopy—

electron microscopy and proximal-probe techniques—and use 

a variety of state-of-the-art imaging and analytical tools. We 

also design and build custom instrumentation and develop novel 

techniques that provide unique capabilities. In our work, we 

collaborate with you to solve materials- and device-related R&D 

problems. This sheet summarizes the uses and features of four 

major tools: transmission electron microscopy, scanning electron 

microscopy, the dual-beam focused-ion-beam workstation, and 

scanning probe microscopy. 

Transmission electron microscopy

In transmission electron microscopy (TEM), a thin sample, less than 

200 nm thick, is bombarded by a highly focused beam of singleenergy electrons. The beam has enough energy for the electrons 

to be transmitted through the sample, and the transmitted electron 

signal is greatly magnified by a series of electromagnetic lenses.

The magnified transmitted signal may be observed in several 

ways—by electron diffraction, diffraction-contrast imaging, or 

phase-contrast imaging. Transmission electron diffraction (TED) 

patterns help to determine the crystallographic structure of the 

material. Diffraction-contrast images yield information about the 

chemistry and microstructure of the material and about its defects. 

Phase-contrast imaging or high-resolution TEM imaging gives 

information about the microstructure of the material and its defects 

at an atomic resolution.

With scanning transmission electron microscopy (STEM), the 

electron beam is raster-scanned across the material, which 

produces a variety of electron and X-ray signals used for 

compositional and electronic analysis. The transmitted electrons 

at high scattering angle can be collected to form high-resolution, 

chemically sensitive Z-contrast images. 

Applications

Crystallography. Electron diffraction enables one to determine 

the crystallographic structure of materials on a fine scale.

Microstructure. Diffraction-contrast and high-resolution TEM 

yields information on the composition, microstructure, and 

atomic structure of materials and defects. High-resolution STEM 

Z-contrast imaging provides directly interpretable, chemically 

sensitive images of the structure of materials, defects, and 

interfaces in samples with atomic resolution.

Composition. Energy-dispersive X-ray spectroscopy (EDS) and 

electron energy-loss spectroscopy (EELS) provide quantitative 

and qualitative compositional analysis of materials to subnm spatial resolution for almost any element. STEM EDS 

and EELS enable elemental mapping to be performed with 

nm-scale resolution. EELS also provides information on the 

electronic properties of materials. A Gatan image filter (GIF) 

enables elemental mapping 

to be performed by energyfiltered TEM with high spatial 

resolution.

Cross-sectional analysis.

Investigates the structure, 

composition, and perfection of 

multilayer films and interfaces.

Features

Field-emission gun 

STEM. Enables structural, 

compositional, and electronic 

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Measurements & Characterization • National Center for Photovoltaics

Analytical Microscopy

High-resolution Z-contrast image of 

a c-Si/a-Si interface from a highefficiency Si heterojunction solar 

cell. The image reveals an atomically 

abrupt and flat c-Si/a-Si interface.

Electron energy-loss spectroscopy at three 

different positions reveals the changes 

of electronic property from the c-Si to 

the interface and to the a-Si regions (see 

peaks indicated by black arrows).

GIF energy-filtered TEM elemental map 

of Ge nanowires embedded in GaInP 

matrix.
analysis with sub-nm 

spatial resolution.

STEM high-angle annular 

dark-field detector. 

Enables high-resolution 

(~0.14 nm) STEM Z-contrast 

microscopy, providing 

directly interpretable, 

chemically sensitive atomic 

resolution images.

Gatan image filter (GIF).

Enables EELS spectroscopy 

and elemental mapping to be performed for a wide range of 

elements and energy-filtered electron diffraction and imaging.

Energy dispersive X-ray spectroscopy (EDS) systems. 

Enables compositional analysis and elemental mapping with high 

spatial resolution.

Low-energy low-temperature ion milling system. Reduces 

damage during sample preparation.

Dual-beam focused-ion-beam (FIB) workstation. Enables 

site-specific preparation of TEM samples.

Scanning electron microscopy

In scanning electron microscopy (SEM), highly energetic (0.1–40 

keV) electrons are focused and scanned over the surface being 

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observed, causing multiple interactions: emission of secondary 

and backscattered electrons, photons, X-rays, excitation of 

phonons, and diffraction under specific conditions. Because the 

electron beam is scanned in the X-Y plane, an image for each of 

these different processes can be obtained when using a suitable 

detector. Detection of secondary electrons—a standard practice 

in SEM—provides the topography of the surface being observed 

with a resolution on the order of 1–2 nm and magnification 

from 10x to 500,000x. In addition, we can map information on 

composition, phase, and other multiple properties (e.g., electrical, 

optical, thermal) with excellent resolution by adding appropriate 

detectors. The SEM is perhaps the most versatile instrument 

in materials science because—beyond being a stand-alone 

instrument—it represents an integrated platform for a wide variety 

of characterization techniques.

Applications

Topography. Secondary electrons, with energies from 0 to 50 eV, 

provide an image of the surface being observed with very high 

resolution and depth of field at very high scanning speeds. Best 

resolution is obtained with in-lens detectors in microscopes with 

field-emission sources.

Composition. Backscattered electron emission is sensitive 

to composition and is used to form compositionally sensitive 

images. Moreover, using characteristic X-rays, maps of different 

elements can be obtained with micrometer resolution.

Electron-beam-induced 

current (EBIC).

In the presence of an 

electrostatic field (p-n 

junction), electron-hole 

(e-h) pairs excited by 

the electron beam 

can be collected, and 

the resulting current 

is amplified with a 

picoamplifier and used 

to form an EBIC image. 

EBIC provides information 

about the location of 

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MAJOR INSTRUMENTATION FOR SCANNING ELECTRON MICROSCOPY

Lateral Special Features

Resolution

System Analytical Technique Typical Applications

Quantitative compositional 100 nm to 5 mm ± 0.2 at.% detection limit

analysis

Electron probe

microanalysis (EPMA)

JEOL JXA-8900L

Scanning tunneling

luminescence,

electroluminescence, lateral

transport measurements, NFCL

Nanoscale characterization and < 1 nm

manipulation of nanostructures

Customized SPM STM, AFM, NSOM

platform

Cathodoluminescence spectrum

imaging, cryostage (15 to 300 K),

CCD, InGaAs PDA

Microstructure, EBIC, 3.5 nm

cathodoluminescence

Scanning electron

microscopy

JEOL JSM-5800

HKL NORDLYS II EBSD

THERMO EDS, EBIC

1.2 nm @ 1.5 kV

2.5 nm @ 1 kV

Micro- and nanoscale

characterization of topography,

composition and phases

Field-emission

scanning electron

microscopy

JEOL 6320F

High-resolution TEM image of array of 

colloidal PbTe nanocrystals.

Maps of photon intensity for different transitions identified on the emission spectrum 

of CIGS thin films. Grain boundaries show a distinct electronic behavior.

1.08 eV 1.02 eV 1 μm Electron-beam-induced current image of a 

GaAsP-on-Si solar cell revealing threading 

dislocations crossing the p-n junction.
the junction in a device, shunts, electrical activity of grain 

boundaries, and diffusion length.

Cathodoluminescence (CL). CL is the photon emission 

stimulated by the electron beam. CL can be used to investigate 

the distribution of recombination centers in semiconductors, 

including extended defects (dislocations, grain boundaries), stress 

fields, and compositional fluctuations. At NREL, we have combined 

spectroscopy and imaging into a single mode: spectrum imaging. 

Basically, spectrum 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. In our system, CL observations can be 

performed at temperatures between 15 and 300 K.

Electron backscattered diffraction (EBSD). EBSD indexes 

diffraction patterns for each pixel on the image, providing maps 

of the orientation of crystalline phases, misorientation between 

grains, texture, grain distribution, deformation, and strain.

Scanning-probe microscopy (SPM) platform. We have 

developed a very compact SPM integrated with SEM. Combining 

these two platforms, the following operation modes are available:

Scanning tunneling luminescence—Based on scanning 

tunneling microscopy (STM), the photon emission is stimulated 

by tunneling electrons and can be applied to nanostructures.

Lateral transport—Based on a combination of STM and SEM, 

e-h pairs excited by the electron beam at specific locations 

are detected through the STM tip and the lateral electron 

diffusion can then be measured.

Electroluminescence mapping—Based on conductive 

atomic force microscopy (C-AFM), individually injected 

current pulses during intermittent contact are used to 

stimulate electroluminescence when the p-n junction is 

under forward bias.

Near-field cathodoluminescence (NFCL)—Based on 

near-field scanning optical microscopy (NSOM), this SPM is 

designed for surface-sensitive cathodoluminescence. The 

luminescence is excited by the electron beam and detected 

through the optical fiber positioned in the near field. 

Dual-Beam Focused-Ion-Beam (FIB) Workstation

This dual-beam instrument consists of a focused-ion-beam (FIB) 

column and a scanning electron microscope (SEM) column on 

the same platform. Uses include ion milling, metal deposition, ion 

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imaging, and electron imaging on the micrometer and nanometer 

scale of advanced photovoltaic materials and devices. Supporting 

other analytical tools such as TEM, the dual-beam FIB performs 

precise, site-specific sample preparation for both TEM and SEM. 

Acquiring chemical spectra and elemental maps is another feature 

of this system with energy-dispersive spectroscopy (EDS). 3D 

chemical reconstructions can be obtained by combining controlled 

ion milling with chemical mapping. The FIB is equipped with a gas 

injection system (GIS) Pt metal deposition capability that can be used 

with either ion-beam-assisted or electron-beam-assisted chemical 

vapor deposition. Using a digital patterning generator also allows 

for complete FIB milling or deposition of complex structures with 

software-supplied parameters and/or by direct input of bitmap files. 

Conductive atomic force microscopy image of CdTe sample after bromine/methanol 

etching shows enhanced electric current at grain boundaries.

Scanning tunneling microscopy image (left) shows morphology of a Si cluster on Si 

surface, and spectroscopic imaging (right) shows spatial mapping of density of states 

at 1 eV above Fermi level.

0 20 μm

NREL’s dual-beam focused-ion-beam workstation for fabricating microscopy samples 

and nanostructures.

CdTe thin film. Electron backscattered pattern (left) and Euler 

orientation map obtained by electron backscattered diffraction (right).

 0 8 nm .

Mike Linenberger, NREL/PIX14514
Scanning Probe 

Microscopy (SPM)

A group of scanning probe 

microscopy (SPM) techniques 

uses very sharp tips that 

scan extremely close (several 

nm) to or in contact with 

the material being analyzed. 

The signal used to map and 

analyze the surface may be 

generated in a number of 

ways: attractive/repulsive 

forces, electric current, 

or even friction force. The 

techniques we use include scanning tunneling microscopy (STM) 

and atomic force microscopy (AFM), with variants such as scanning 

Kelvin probe microscopy (SKPM), conductive AFM (C-AFM), 

scanning capacitance microscopy (SCM), and scanning tunneling 

spectroscopy (STS).

Features

Spatial resolution to atomic scale.

Digital data acquisition, allowing real 3D imaging and 

measurements such as roughness and surface linescan.

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Nondestructive.

Can be performed in air or in ultra-high vacuum.

Field of view is from atoms to about 100 μm 

(vertical limit of 7 μm).

AFM uses the force between the tip and sample surface; STM 

uses the tunneling current between the tip and sample surface.

Applications

Surface imaging. Scans the surface of materials to produce 

topographic images with up-to-atomic resolution.

Electrical and electronic properties. Can obtain these 

properties of samples with excellent spatial resolution. Analysis 

of properties that include surface potential (SKPM), type and 

concentration of charge carriers (SCM), electric conductivity 

(C-AFM), and local density of states (STS).

Various materials. Can be used to analyze most types of 

materials, from conductors to insulators. Can provide information 

on the properties of semiconductor devices—e.g., potential 

profile along p-n junctions by analyzing their cross sections.

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MAJOR INSTRUMENTATION FOR SCANNING PROBE MICROSCOPY

Vertical Vacuum

Resolution (A)

Lateral

Resolution (A)

System Analytical Technique Typical Applications

10 -11 Nanoscale and atomic characterization < 1 < 0.1 torr range

of sample morphology and

electrical/electronic properties

AFM, STM, SKPM,

C-AFM

Nanoscale characterization of sample < 1 < 0.1 No

morphology and electrical properties,

including close-loop tip positioning

AFM, STM, SKPM,

SCM, C-AFM

Nanoscale characterization of sample < 1 < 0.1 No

morphology and electrical properties

AFM, STM, SKPM,

SCM, C-AFM

Nanoscale characterization of sample < 1 < 0.1 No

morphology and electrical properties

AFM, STM, SKPM,

SCM

Veeco AutoProbe CP

Veeco Dimension 

3100 – Nanoscope 

IIIa

Veeco Dimension 

3100 – Nanoscope V

Omicron 

VT-STM/AFM

O O

Electrical potential image of a III-V 

multijunction cell from scanning Kelvin 

probe microscopy.

National Renewable Energy Laboratory

1617 Cole Blvd., Golden, CO 80401

NREL is a national laboratory of the U.S. Department of Energy,

Energy Efficiency and Renewable Energy,

operated by Midwest Research Institute • Battelle

Measurements and Characterization is within the

National Center for Photovoltaics at NREL

Web site: www.nrel.gov/pv/measurements

Phone: (303) 384-6675 • Fax: (303) 384-6604

Contract No. DE-AC36-99-GO10337

NREL/BR-520-40120 • June 2006 Printed on paper containing at least 50% wastepaper, including 20% postconsumer waste

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