What is an X-ray Diffraction (XRD) Report ?
FAQ: What is an X-ray Diffraction (XRD) Report in Crystal Substrate Terminology?
Q1: In the context of substrate industry terminology, what is an X-ray Diffraction (XRD) report?
A: An XRD report stands for X-ray Diffraction report. It is a specialized test report used to detect the structure, orientation, and purity of a single crystal by utilizing the phenomenon of X-ray diffraction.
An XRD pattern is a record of the diffraction caused by the interaction between X-rays and the atomic structure of a crystal. It reflects the regular arrangement of atoms within the crystal; different crystal structures produce unique XRD patterns. Because every crystal structure has its own unique "fingerprint" pattern, it serves as a critical basis for structural identification. XRD patterns are widely applied in fields such as materials science, chemistry, and physics, serving as an essential tool for gaining insight into the microscopic structure and properties of materials.
Q2: What are the steps involved in analyzing an XRD pattern?
A: The analysis of an XRD pattern can be divided into three main stages: peak position determination, peak intensity analysis, and peak shape study.
- Peak Position Determination
The peak position refers to the angular location of the diffraction peaks in the XRD pattern. By accurately measuring these positions, the interplanar spacing ($d$-spacing) of the crystal can be determined. This is the foundation of crystal structure analysis, as different spacings correspond to different crystal structures.
- Peak Intensity Analysis
Peak intensity refers to the strength of the diffraction peaks, which is related to the types, quantities, and arrangement of atoms within the crystal. Changes in intensity provide information regarding atomic distribution. For instance, in multiphase materials, the ratio of intensities between different phases reflects their respective concentrations.
- Peak Shape Study
Peak shape includes characteristics such as width and symmetry. Variations in shape reflect information like grain size and lattice defects. A broader peak may indicate smaller grain sizes or the presence of lattice defects, while a sharp peak typically signifies larger grains and a more intact lattice structure.
Q3: What is the role of XRD patterns in practical applications?
A: XRD patterns help determine a material's crystal structure, phase composition, grain size, and other critical data. They play a vital role in material research and development (R&D) and quality control.
Q4: What is the underlying principle of XRD pattern formation?
A: After X-rays are generated, they interact with the atomic structure of the crystal. Through the principle of optical interference, diffraction occurs. By analyzing these diffraction phenomena, the crystal structure can be decoded. Below is a detailed explanation of X-ray generation, interaction with matter, and the Bragg equation.
- Generation of X-rays
When high-speed electrons collide with matter, they interact with the atoms therein, causing energy transfer. The lost energy is released as X-rays in two forms: a continuous spectrum and a characteristic spectrum.
- Interaction of X-rays with Matter
When X-rays pass through matter, their intensity attenuates due to scattering and absorption.
- The Bragg Equation
XRD structural analysis experiments determine the structure of a substance by comparing the diffraction phenomena that occur after X-rays pass through it. When X-rays strike a set of crystal planes with a spacing similar in magnitude to their wavelength, and if that plane acts as a Bragg plane, the following applies:
2dsinθ=nλ,n=1,2...
This formula is the law of X-ray diffraction in crystals, also known as Bragg's Law.
- Working Principle of X-ray Phase Diffraction Analysis
Crystalline solids act as diffraction gratings for X-rays. Coherent scattering produced by a vast number of particles results in light interference, which enhances the intensity of the scattered X-rays at specific angles. The beam of maximum intensity formed by the superposition of wavefronts and mutual interference is called the X-ray diffraction line. When the diffraction conditions are met, the Bragg equation is applied:
2dsinθ=nλ
Q5: In the crystal substrate industry, what does an authentic XRD report actually look like?
A: The following is an authentic X-ray Diffraction (XRD) report for a YAlO3 (Yttrium Aluminate) crystal, commonly referred to as a YAP crystal. This test report is provided by Shalom EO.
XRD report:
Quality Mark: Calculated
d-Value: Calculated
Intensity (I): Unknown
Material: Yttrium Aluminium Oxide (YAlO3)
Experimental Parameters
Radiation: CuKa1
Wavelength: 1.5406
Filter:
Calibration:
2θ Range: 20.996 – 69.870
I/Ic (RIR/K-Value): 3.88
Reference: Calculated by Jade from ICSD entry #83027 (on 06/02/10)
Crystal Structure
Crystal System: Orthorhombic
Space Group: Pbnm (62)
Z (Formula Units per Cell): 4
Unit Cell Parameters: 5.1671 x 5.3148 x 7.3538 <90.0 x 90.0 x 90.0>
P.S. (Pearson Symbol):
Density (Calculated): 5.39
Density (Measured):
Molecular Weight:
Volume: 202.0
Reference: Same as above
Diffraction Characteristics
Strongest Lines (d/I): 2.61/X, 1.85/3, 3.70/3, 2.11/3, 1.50/2, 2.58/2, 2.15/2, 2.66/2
Notes:
- FIZ#83027: "Distortion of Gd Fe O3 -type perovskites with pressure: a study of Y Al O3 to 5 GPa", Ross, N.L., Phase Transition, v58 (1996) 27-41, R=0.034.
- The structure has been assigned a PDF number (calculated powder diffraction data): 01-087-1288.
- Temperature factors available.
- Structure type : Perovskite-GdFeO3.
- X-ray diffraction from single crystal
2θ |
d-spacing (Å) |
I(f) |
( h k l) |
θ |
1/(2d) |
2π/d |
n^2 |
20.996 |
4.2278 |
0.9 |
( 1 0 1) |
10.498 |
0.1183 |
1.4862 |
|
24.001 |
3.7048 |
26.7 |
( 1 1 0) |
12.000 |
0.1350 |
1.6960 |
|
24.186 |
3.6769 |
16.3 |
( 0 0 2) |
12.093 |
0.1360 |
1.7088 |
|
26.925 |
3.3086 |
17.9 |
( 1 1 1) |
13.463 |
0.1511 |
1.8990 |
|
33.700 |
2.6574 |
20.9 |
( 0 2 0) |
16.850 |
0.1882 |
2.3644 |
|
34.334 |
2.6098 |
100.0 |
( 1 1 2) |
17.167 |
0.1916 |
2.4076 |
|
34.693 |
2.5836 |
24.3 |
( 2 0 0) |
17.347 |
0.1935 |
2.4320 |
|
35.903 |
2.4992 |
10.3 |
( 0 2 1) |
17.952 |
0.2001 |
2.5141 |
|
38.047 |
2.3632 |
0.4 |
( 1 2 0) |
19.024 |
0.2116 |
2.6588 |
|
38.721 |
2.3236 |
0.9 |
( 2 1 0) |
19.361 |
0.2152 |
2.7041 |
|
40.043 |
2.2499 |
0.7 |
( 1 2 1) |
20.022 |
0.2222 |
2.7927 |
|
40.690 |
2.2156 |
5.4 |
( 2 1 1) |
20.345 |
0.2257 |
2.8359 |
|
40.707 |
2.2147 |
2.1 |
( 1 0 3) |
20.354 |
0.2258 |
2.8371 |
|
41.912 |
2.1538 |
22.0 |
( 0 2 2) |
20.956 |
0.2321 |
2.9173 |
|
42.741 |
2.1139 |
26.1 |
( 2 0 2) |
21.370 |
0.2365 |
2.9723 |
|
44.271 |
2.0443 |
7.3 |
( 1 1 3) |
22.136 |
0.2446 |
3.0735 |
|
45.595 |
1.9880 |
1.9 |
( 1 2 2) |
22.797 |
0.2515 |
3.1606 |
|
46.178 |
1.9642 |
1.1 |
( 2 1 2) |
23.089 |
0.2546 |
3.1988 |
|
49.144 |
1.8524 |
31.5 |
( 2 2 0) |
24.572 |
0.2699 |
3.3919 |
|
49.542 |
1.8385 |
20.6 |
( 0 0 4) |
24.771 |
0.2720 |
3.4177 |
|
50.620 |
1.8018 |
6.8 |
( 0 2 3) |
25.310 |
0.2775 |
3.4872 |
|
50.786 |
1.7963 |
11.0 |
( 2 2 1) |
25.393 |
0.2784 |
3.4979 |
|
53.842 |
1.7013 |
0.7 |
( 1 2 3) |
26.921 |
0.2939 |
3.6931 |
|
54.359 |
1.6863 |
1.4 |
( 2 1 3) |
27.180 |
0.2965 |
3.7259 |
|
54.688 |
1.6770 |
<1 |
( 3 0 1) |
27.344 |
0.2982 |
3.7467 |
|
54.729 |
1.6758 |
<1 |
( 1 3 0) |
27.364 |
0.2984 |
3.7493 |
|
55.501 |
1.6543 |
2.6 |
( 2 2 2) |
27.751 |
0.3022 |
3.7980 |
|
55.776 |
1.6468 |
5.5 |
( 1 1 4) |
27.888 |
0.3036 |
3.8153 |
|
56.085 |
1.6385 |
3.2 |
( 3 1 0) |
28.043 |
0.3052 |
3.8348 |
|
56.255 |
1.6339 |
16.8 |
( 1 3 1) |
28.127 |
0.3060 |
3.8454 |
|
57.587 |
1.5993 |
2.6 |
( 3 1 1) |
28.794 |
0.3126 |
3.9288 |
|
60.681 |
1.5249 |
9.9 |
( 1 3 2) |
30.341 |
0.3279 |
4.1203 |
|
61.259 |
1.5119 |
9.6 |
( 0 2 4) |
30.630 |
0.3307 |
4.1558 |
|
61.894 |
1.4979 |
11.7 |
( 2 0 4) |
30.947 |
0.3338 |
4.1946 |
|
61.954 |
1.4966 |
24.4 |
( 3 1 2) |
30.977 |
0.3341 |
4.1983 |
|
62.828 |
1.4779 |
3.5 |
( 2 2 3) |
31.414 |
0.3383 |
4.2515 |
|
63.634 |
1.4611 |
0.2 |
( 2 3 0) |
31.817 |
0.3422 |
4.3004 |
|
64.126 |
1.4511 |
<1 |
( 1 2 4) |
32.063 |
0.3446 |
4.3301 |
|
64.410 |
1.4453 |
0.5 |
( 3 2 0) |
32.205 |
0.3459 |
4.3472 |
|
64.590 |
1.4417 |
<1 |
( 2 1 4) |
32.295 |
0.3468 |
4.3580 |
|
65.029 |
1.4331 |
0.3 |
( 2 3 1) |
32.515 |
0.3489 |
4.3844 |
|
65.797 |
1.4182 |
0.1 |
( 3 2 1) |
32.898 |
0.3526 |
4.4304 |
|
65.987 |
1.4146 |
0.4 |
( 1 0 5) |
32.993 |
0.3535 |
4.4418 |
|
66.267 |
1.4093 |
0.3 |
( 3 0 3) |
33.134 |
0.3548 |
4.4585 |
|
67.669 |
1.3834 |
8.1 |
( 1 3 3) |
33.835 |
0.3614 |
4.5417 |
|
68.596 |
1.3670 |
0.8 |
( 1 1 5) |
34.298 |
0.3658 |
4.5964 |
|
68.872 |
1.3622 |
0.4 |
( 3 1 3) |
34.436 |
0.3671 |
4.6126 |
|
69.125 |
1.3578 |
<1 |
( 2 3 2) |
34.563 |
0.3682 |
4.6274 |
|
69.870 |
1.3451 |
0.1 |
( 3 2 2) |
34.935 |
0.3717 |
4.6710 |
|
Tags: XRD report, X-ray diffraction report, crystal substrate XRD, crystal wafer characterization