Transcript The X-Ray SEF - Massachusetts Institute of Technology

The X-Ray SEF
Scott Speakman
13-4009A
x3-6887
[email protected]
http://prism.mit.edu/xray
This molecule is essential to life…
http://prism.mit.edu/xray
Intensity (a.u.)
The crystal structure of caffeine
was solved using X-ray diffraction
10
15
20
25
30
2q (deg.)
D. June Sutor, Acta Cryst. 11 (1958) 453
http://prism.mit.edu/xray
Caffeine is a crystal because its molecule
repeats in an orderly manner to fill space
http://prism.mit.edu/xray
X-Ray Diffraction is used to study
crystalline materials
 X-rays scatter off of the
atoms in a sample
 If those atoms are
systematically ordered, the
scattered X-rays tell us:
 what atoms are present
 how they are arranged
http://prism.mit.edu/xray
The XRD pattern of every crystalline
material is as distinct as your fingerprint
Intensity (a.u.)
Anhydrous Caffeine C8H10N4O2
Caffeine Hydrate C8H10N4O2H2O
10
15
20
25
30
2q (deg.)
http://prism.mit.edu/xray
Basic Diffractometer Operation
X-ray
tube
q
q
2q
Intensity (a.u.)
Detector
10
15
20
25
2 q (deg.)
30
 A detector rotates around the sample, measuring
intensity as a function of the diffraction angle 2theta
 XRD uses information about the position, intensity, width,
and shape of diffraction peaks in a pattern from a
polycrystalline sample.
http://prism.mit.edu/xray
The X-ray SEF has
 Rigaku High-Speed Powder Diffractometer
 PANalytical X’Pert Pro Multipurpose
Diffractometer
 Bruker D8 Diffractometer with 2D Detector
 Bruker D8 High-Resolution Thin-Film
Diffractometer
 PANalytical Back-Reflection Laue Single
Crystal Diffractometer
 Bruker Apex Single Crystal Diffractometer
 Bruker Small Angle X-ray Scattering
Instrument
http://prism.mit.edu/xray
Sample Requirements
The Ideal Sample
 Sample Size
 Powder: 90 to 482 mm3
 minimum 1.6 mm3
 Solid: 10mm x 10mm
 min: 1mm x 1mm
 max: 55mm x 25mm
 1” to 6” wafer
 Characteristics
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flat
grain size <10 mm
smooth
densely packed
infinitely thick (>0.3mm)
Real Samples
 Multilayers:
 Co(10nm)/Fe(15nm)/MgO(
2nm)/Si
 42 alternating layers of
GaAs(104nm) and
Al0.941Ga0.059As(127nm)
 Powder
 3 specks of blue paint
 0.05mm thick coating of
air-sensitive battery
materials
 brake rotor
 particles in suspension
http://prism.mit.edu/xray
Analyses Done Routinely
in the X-ray SEF
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Discussed Today
Phase Identification
Crystallite Size Estimation
Lattice Parameter Refinement
Residual Stress Analysis
Evaluate Thin Film Quality
Reflectivity for Multilayer Thin
Film Analysis
Small Angle Diffraction of
Nano- and Meso- structures
Microdiffraction
Texture Analysis
In-situ Diffraction
Other Techniques
 Index and Solve Crystal
Structures
 Percent Crystallinity
 Thin Film Analysis
 Reciprocal Space Mapping
 Relaxation & Strain
 Defect Density
 Single Crystal Diffraction
 Crystal Orientation
 Twinning & Other Defects
 Small Angle X-ray Scattering
 order/disorder of polymers
 microstructure and porosity
 amorphous texture
http://prism.mit.edu/xray
Phase Identification and Quantification
What phases, and how much of each, are present in this mixture of pigments?
21 wt%
Anatase, TiO2
Red Paint Pigment Mixture
Intensity (a.u.)
28 wt%
Hematite, Fe2O3
51 wt% Rutile, TiO2
25
30
35
40
2q (deg.)
http://prism.mit.edu/xray
Crystallite Size Analysis
Are any of the phases nanocrystalline; if so, what is their average crystallite size?
Red Paint Pigment Mixture
Intensity (a.u.)
Rutile: XS> 100 nm
Anatase: XS= 25 nm
Hematite: XS> 100 nm
22
23
24
25
26
27
28
29
2q (deg.)
http://prism.mit.edu/xray
Lattice Parameter Refinement
La2Zr2O7 undoped
4% Y-doping
8% Y-doping
10.821
4.0E-04
3.5E-04
10.818
3.0E-04
2.5E-04
10.815
2.0E-04
1.5E-04
10.812
Conductivity (S/cm)
Lattice Parameter (A)
Intensity (a.u.)
How does doping change the lattice parameter of this fuel cell electrolyte?
1.0E-04
10.809
5.0E-05
0
5
10
mol% Y
28.0
28.5
29.0
29.5
2q (deg.)
http://prism.mit.edu/xray
in situ XRD
 we can perform these analyses, and many more, as a
function of:
 temperature
 cryostat: 11 K to RT
 Powder Furnace: RT to 1200 C
 Plate Furnace: RT to 900 C
 environment
 air
 vacuum
 inert gas
 mildly reactive gas
 time
 time resolution as fast as 10 sec
 more typical is 5+ min time resolution
http://prism.mit.edu/xray
in situ XRD of lattice parameters
How does the lattice parameter of LSO change with temperature?
1.5
c axis
1.3
1.1
b axis
0.7
0.5
0.3
a axis
delta L/Lo (%)
Intensity (a.u.)
0.9
0.1
-0.1
angle b
21
22
23
24
25
2q (deg.)
26
27
28 0
-0.3
-0.5
200
400
600
800
1000
1200
1400
1600
Temp (C)
http://prism.mit.edu/xray
in situ XRD of phase composition
How does the phase composition of this hydrogen
storage material change with time at 150°C?
NaH
Na3AlH6
NaAlH4
Al
N NaAlH4  N
 k1t
0
NaAlH4
e
Phase Quantity (wt %)
80
60
40
20
N Na3 AlH6 
1 0
k1  k1t

e
N
 ek 2t  N 0
ek 2t
Na3 AlH6

3 NaAlH4 k 2  k1 
0
0
10000
20000
30000
40000
50000
60000
70000
Elapsed T ime (sec)
http://prism.mit.edu/xray
80000
Residual Stress Analysis
How do stresses in a Pd film change with H2 and temperature?
60
Pd in H2
Pd in He
Stress (MPa)
40
Intensity (a.u.)
XRD at 50°C
20
39.4 39.5 39.6 39.7 39.8 39.9 40.0 40.1 40.2 40.3 40.4 40.5 40.6 40.7
2q (deg.)
0
H2
-20
Pd
-40
Hastelloy
-60
0
100
200
300
400
500
600
Temp (°C)
http://prism.mit.edu/xray
Texture Pole Figures
How are the grains oriented in this refractory alloy for a satellite power system?
Distribution of <100> and <111>
directions in rolled Nb-1Zr
Rolled to 20% Reduction in Thickness
(less deformed)
Rolled 95% Reduction in Thickness
(more deformed)
http://prism.mit.edu/xray
Thin Film Rocking Curve
What is the quality of epitaxial semiconductor thin films
compared to the perfect single crystal substrate?
Poor Epitaxial Thin Film
Good Epitaxial Thin Film
Intensity (a.u.)
Perfect Single Crystal Substrate
Horrible Quality, Not Epitaxial
At All, Thin Film
30.6
30.7
30.8
30.9
31.0
31.1
31.2
31.3
31.4
2 q (deg.)
http://prism.mit.edu/xray
Thin Film Reflectivity
What is the arrangement and surface characteristics of a thin film of
GaAs on a Si substrate?
Thickness Roughness Density
(nm)
(nm)
(g/cm3)
C
9.2
1.09
0.98
Ga2O
1.02
0.20
2.89
GaAs
19.4
0.35
5.32
SiO2
2.1
0.71
2.76
Si
∞
0.31
2.33
Log Intensity (a.u.)
3
1
2
3
4
5
2 q (deg.)
http://prism.mit.edu/xray
Glancing Incident Angle Small Angle
X-ray Diffraction
Do quantum dots arrange themselves in a systematic manner with long range order?
What is the average distance between the quantum dots?
Intensity (a.u.)
10.056nm
5.901nm
5.150nm
3.924nm
88.27
58.85
44.14
35.31
29.43
25.22
d-spacing
(Å)
q
http://prism.mit.edu/xray
Microdiffraction
How does the diffraction pattern change at different positions on a sample?
http://prism.mit.edu/xray
Group classes are held regularly to train
you to use the X-ray lab independently
 Training for Self-Use Requires
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1 hour X-ray Safety Course from EHS
1 hour Lab Specific Safety Training
2 hr Instrument Specific Training
2 hr Practical XRD Lecture
3 hr Data Analysis Workshop
 next session: late January or early February
 see prism.mit.edu/xray for schedule updates
http://prism.mit.edu/xray
Assisted Use
 I will gladly work with you to collect and
analyze data
 usually needs to be scheduled ~2 weeks in
advance
http://prism.mit.edu/xray
Contact Information
 Scott Speakman
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office: 13-4009A
x3-6887
[email protected]
generally available 10 am to 4 pm
 XRD Lab: 13-4027
 XRD Computer Room: 13-4041
 http://prism.mit.edu/xray
Upcoming IAP Lectures
 Introduction to X-Ray Diffraction
 Jan 17, 2-5 pm, room 13-2137
 Nanocrystallite Size Analysis using XRD
 Jan 24, 2-5 pm, room 13-2137
 Thin Film Analysis using X-rays
 Jan 31, 2-5 pm, room 13-2137
http://prism.mit.edu/xray
Workshops for Existing X-Ray Users
 Basic Data Analysis with Jade
 scheduled on request
 Rietveld Refinement using HighScore Plus
 Jan 29 and Jan 30, 1 to 5 pm
 room 13-4041
 RSVP by Jan 25
http://prism.mit.edu/xray