You can use SAED pattern to see (i) if your sample is amprohous (diffuse rings), crystalline (bright spots), polynanocrystalline (small spots making up a rings, each spot arising from Bragg reflection from an individual crystallite), see page 110 of the attached book that i highlighted for you

(ii) find out the crystalline phase of your sample (each phase has a characteristic SAED pattern

Here I explain the step-by-step method to index the SAED patter

(i) measure the diameter, 2R, of each ring using some image processing software such as Image tool, for example. Lets say for the first ring, the 2R = 5.37 [1/nm]

(ii) obtain the value of radius, R, (w.r.t central spot); R= 2.68 [1/nm], the unit 1/nm means the distance is in reciprocal lattice

(iii) Obtain the interplanar distance (d), in real space, as 1/R; in our case d= 1/R = 1/2.68 =0.372 nm. note that the unit is nm now, as we are talking about real space.

Let us consider my sample is TiO2, I know (by comparsion with d-value of different phases in literature) that a d-value of 0.372 correspond to (101) plan of anatase TiO2.

(iv) Now you found the d value for 1 ring. Do the same for procedure to obtain d-values for other rings.

(v) compare the d-value (each of which correspond to a certain set of hkl indices) with the the diffraction data from literature (and you know what is the compositi

on of your sample), for example from http://rruff.geo.arizona.edu/AMS/amcsd.php

or ICSD data base.

In this way, you can index the SAED pattern and assign each ring an hkl value. In other words, you can find in which crystalline form your sample is.

Good Luck!

SAED is the diffraction pattern obtained in the reverse space of the lattice planes.

It is used in order to find the d-spacing of the crystal planes, you will have to find the radius of the spots that you observe in the SAED pattern from the bright center. Then using the camera constant you can calculate the d-spacing.

Using a data base, you can then find the proper cell parameters and the Miller indices of the diffraction pattern.

Dear Gaurav,

As you already know SAED is the SELECTED AREA ELECTRON DIFFRACTION PATTERN, which will guide us about the indices based on which we can calculate the d-spacing. Additionally the pattern also informs us about the crystallinity of the samples. The brighter the spots the crystalline is the particles (as shown in your case).

Good Luck !!

Simply and shortly, it gives you information about crystallinity and specifically about the electron diffraction pattern from a selected area. For more details, you can follow the link by Sir. Klemm.

Good luck!

You can use SAED pattern to see (i) if your sample is amprohous (diffuse rings), crystalline (bright spots), polynanocrystalline (small spots making up a rings, each spot arising from Bragg reflection from an individual crystallite), see page 110 of the attached book that i highlighted for you

(ii) find out the crystalline phase of your sample (each phase has a characteristic SAED pattern

Here I explain the step-by-step method to index the SAED patter

(i) measure the diameter, 2R, of each ring using some image processing software such as Image tool, for example. Lets say for the first ring, the 2R = 5.37 [1/nm]

(ii) obtain the value of radius, R, (w.r.t central spot); R= 2.68 [1/nm], the unit 1/nm means the distance is in reciprocal lattice

(iii) Obtain the interplanar distance (d), in real space, as 1/R; in our case d= 1/R = 1/2.68 =0.372 nm. note that the unit is nm now, as we are talking about real space.

Let us consider my sample is TiO2, I know (by comparsion with d-value of different phases in literature) that a d-value of 0.372 correspond to (101) plan of anatase TiO2.

(iv) Now you found the d value for 1 ring. Do the same for procedure to obtain d-values for other rings.

(v) compare the d-value (each of which correspond to a certain set of hkl indices) with the the diffraction data from literature (and you know what is the compositi

on of your sample), for example from http://rruff.geo.arizona.edu/AMS/amcsd.php

or ICSD data base.

In this way, you can index the SAED pattern and assign each ring an hkl value. In other words, you can find in which crystalline form your sample is.

Good Luck!

Thus using the SAED, we can identify the crystal (which we often already know)

and its orientation (which we probably don’t) with respect to both the beam and to any

adjacent crystals. The positions of the allowed hkl reflections are characteristic of the crystal system. Indexing associates each spot or ring in the DP with a plane (hkl),or set of planes {hkl}, in the crystal. From the indexing of the spots, you can deduce the orientation of the crystal in terms of the zone axis [UVW] in which the indexed planes lie [Reference book attached]

I just measured the diamter (2R) of the 1st ring of your SAED and the resulting image is attached. Also see the link

http://arxiv.org/ftp/arxiv/papers/1111/1111.0260.pdf

Thanks everyone.

Sir

I have taken SAED for graphene. I can only see some three bright spots instead of hexagonal pattern.  Can anyone explain why it happens.   

How will you find out the growth orientation  of a particular layer from the SAED pattern for a multilayer film. (let us say it has three layers: a buffer layer, the film layer and cap layer)

Sajjad Sir

Can u  explain me how to calculate d?I mean is it always 1/R or does it vary depending upon the crystal?

 In the above SAED image which has the units like 2 1/nm, what does that 2 indicate , Is it the number of rings present ??and what value should I enter to set scale in imagej software, if I have the units like 5 1/nm ?

Thank you.

Dear Seenivas

The small bar at the bottom is the length measurement indicated by the units (e.g. 2 or 5). 1/nm is the units. As you are in reciprocal space the units is inverse of the space units. 

So when you use the imageJ software the small scale bar is 2 or 5 value and the units will be 1/nm

Hope this helps. 

Dear All, How to analyse saed of rod type pattern not nanoparticles???

do you have photo of saed?

thanks for all answer 

d is not always 1/R. The actual relation is R*d= L* wavelength of the x-ray. L is the camera constant.

SAED diffraction patterns are either few spot patterns corresponding to nano particle diffraction or few ring patterns corresponding to nano powder diffraction

Dear All,

I have SAED image of InP nanowire and wanted to calculate the lattice constant. I tried to measure the distance between spots in image J, but it looks like i'm getting wrong measurements when i try to measure distance diagonally. I measured the bar line on the image, then entered known value in "set up scale". Surprisingly  the measurement works only horizontally (I think the problem is that diagonally the number of pixels across the line is bigger then horizontally because the line is not ideally straight. it has a zig-zag  shape). Also I wanted to make sure that i'm measuring the distance between right spots. 

This is my first time I'm calculating the lattice spacing and would appreciate any help.

Thank you!

David  I tried to open your pictures, but there is some problem with link, as far as I can see just from picture, your SAED is single crystal, I think protocol for calculating is different than when ring patter, please share your protocol.

Could anyone give me all the d-spacing values and corresponding planes of CsPbBr3 NCs? I need to assign a particular d-spacing value to a particular plane. Though I calculated all the d-spacing values, I could not assign all the d-spacing values to different planes. Here are all the d-spacing values of CsPbBr3 nanocrystals: d = 5.70, 4.00, 2.85, 2.54, 2.25, 1.81, 1.43, and 1.27 angstrom

Hi Stefan,

Thank you for your response. Yes it's a single InP crystal and the lattice spacing is calculated by this formula: d=λL/r .  where λ- is the wavelength of electrons (for 200K 0.0025nm) and L is the camera length (in my case 320nm) 

My problem is the measurement of r-the distance between the central spot and the diffracted spot. Do you know any software where I can measure the r distance diagonally ?

Please find attached diffraction images ( I attached more images with 3 different angles)

you can download them

Thanks,

David

• the images is tif format I cannot open them, 
• you can use JImage https://imagej.nih.gov/ij/
• just compare with scale I think you can do it. 
• i think that is not correct protocol for single crystal, let me check my lecture notes.

Great information. Thanks everyone one here.

SAED patterns are the unique signature of the crystals. Whether the crystals are polycrystalline or single crystalline. And the pattern gives important clue about the crystal structure.

how to find a zone axis for an array of hexagonal symmetry dots?

How to find out difference between 2 phases in SAED pattern.

Thanks for the information.

I respect the first answer specially, and the rest of answers truly

SAED pattern indicates the presence of XRD planes

Beautiful images

Well said Prof. Sajjad Ullah .

Also, you may read this book for more information's "Practical electron microscopy in materials science by J.W. Edington"

SAED patterns are the unique way to characterization of the crystals structure. Whether the crystals are single or polycrystalline. And the pattern gives important clue about the crystal structure.

By using SAED pattern, if sample is amprohous (diffuse rings), crystalline (bright spots), polynanocrystalline (small spots making up a rings) each spot arising from Bragg reflection from an individual crystallite)

The origin of these reflections can be determined using a dark field imaging technique. The reflections themselves aren't of much use but if you take a group of about 100 or so particles and put selected area aperature around them, you can generate a ring pattern. From this you have a more complete idea of the d-spacing in the unit cell. In simple structures these can be indexed of spacing matched to a jcpdf card.

SAED is a crystallographic experimental technique that can be performed inside a transmission electron microscope

Exactly.

As i said in first note, very little information is here. You know that something is crystalline because you have a weak image of what looks to be a low order zone axis taken with a selected area aperture and parallel illumination. More work is needed.

My first note outlined a procedure i used sucessfully to prove the crystallinity of 3 nanometer particles. This work i did for John Bradley and is part of the publications listed on my membership. I'm guessing that you may have the additional problem of beam sensitivity and damage from electron interactions. Someone much better at this than myself once said "It's hard enough to do analytical electron microscopy without having to do it in 3 seconds." I was fortunate. I worked in metallurgy. Very friendly samples in the beam.

Prof. Sajjad Ullah answer is helpful. thank you

Sajjad Ullah Appreciable discussion ! what actually the size of the ring diameter show ?

In the event that you have got a SADP like you have shown in the attached image to the question, it is likely that your SAED aperture was placed on less number of rings. The diffused rings may also be a contribution from the carbon film (that is amorphous).

It could also imply at some crystallinity in your sample. Implying there are large grains in addition to fine grains.

A proper nanocrystalline SADP will look like this.

P.S. It can be better than this.

Dear Boruah,

As we know that Selected area (electron) diffraction (SAED), is a crystallographic experimental technique that can be performed inside a transmission electron microscope (TEM). Selected Area Electron Diffraction (SAED) is very important technique to determine the crystal structure of any material. It is a complementary technique in TEM in which the electrons are diffracted at a selected area and bright spots with dark background are observed as a result of this.

d value calculation:

Distance between two bright spots (D) = 2 × Radius of that circle

The distance is in reciprocal space so we take inverse to convert it into real space

Thus, the formula for Interplanar spacing (d):

Interplanar spacing (d) = 2 / Distance between two bright spots

From the SAED pattern we get following important information; we can see (i) if your sample is amprohous (diffuse rings), crystalline (bright spots), polynanocrystalline (small spots making up a rings, each spot arising from Bragg reflection from an individual crystallite).

Hope this information will be help you.

Good Luck.

I aslo got the required information from your answers, it is a valuable discussion, thank you for all

Selected Area Electron Diffraction (SAED) is very important technique to determine the crystal structure of any material. From SAED pattern you can conclude either your particle is in crystalline/amorphous/poly-crystalline form.

SAED is electron crystallography technique in TEM to determine the nature of your materials , weather it is single crystalline/poly-crystalline/amorphous.

Thank you everyone for making it quite informative!

Dear Sadanand Pandey ,

I found your complete answer really helpful. Tnx for sharing !

Hi, Himangshu.

Please refer to the following paper. It gives you enough information to analyze SAED patterns. Specifically, check the supplementary information for detailed calculations.

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