Hi Maido, This is probably the most helpful video about the SEM I've watched, you're using a modern SEM and you're not making it too complicated, thanks a lot! The only thing that I wish you had shown was the elemental composition analysis because that still confuses me a bit whenever I try it. One question: how do you decide which accelerating voltage to use for studying a certain specimen, and why is it important?
***** Thank you, that's very helpful! Yeah, the part when the analysis program gives me weird elements for the peaks is what I'm having problems with, but I hope that as I use the SEM more it'll be much easier. Glad to know that I'm not the only one for whom that happens to. Thanks :)
Thanks! Actually we have a whole series dedicated to sample preparation as each case requires a unique approach. Here is the link to the videos: ruclips.net/video/fnRnoJigsu0/видео.html
Thanks a lot! We might make an updated version of the video at some point in the future as the hardware of our company received a major upgrade, allowing us to make better animations.
Arcanity, the choice of accelerating voltage, or beam energy, is complicated. First, in most SEMs, resolution is better at higher voltages. If you are lucky enough to have a modern field emission system, then you can go to very low voltages at high mags. Besides that, more surface detail is visible at low energies. Also, less damage happens at low energy. Finally, sample charging depends on beam energy. If you play with the accelerating voltage for nonconducting samples, then you might get lucky and find a value for which the primary electron flux balances the secondary and backscattered electron fluxes, and charging can be minimized. That is tricky business. In general, use the lowest energy you can get away with and still have the resolution that you need. Of course, if you do EDX, then you must use certain voltages to get the signal that you are looking for.
Thanks for the feedback. You might want to check out our "under the scanning electron microscope" series, where we also use EDS :) ruclips.net/video/fnRnoJigsu0/видео.html
Thanks! Please share your opinion on bench top SEM. We were thinking of getting one for the students to play with. The other ones here might be interested in your feedback as well since a bench top SEM is generally obtainable already at a low price.
A very useful video. Thank you very much. I have a question: doesn't the electron beam damage the sample ? and how thick can the sample be in order to withstand the electrons ? Thank you in advance !
Hello and thank you for the question! It really depends on the sample and the beam current. If the beam current is sufficiently high, then it is possible to drill a hole through any material. In scanning electron microscopy one should use as low beam current as possible when studying substrates that get easily damaged by electrons. Coating the sample with a thin layer of conductive material (Au, Pt) would also help a lot. I remember how I once had NaOH crystals on the substrate and they were destroyed rather fast under the electron beam (barely got 1 image). Conductive carbon nanotubes on the other hand are much easier to study as the charge and heat is quickly carried away. So ideally you can easily study nanoparticles if they are properly prepared (e.g. apply nanopowder on silver paste on a conductive holder).
Hi. U have a great video here! I have a question. Can SEM analyze the microstructure of a metal surface that is covered with epoxy but with exposed area of 10mm^2 only??
If the surface is covered with epoxy, then you'll see only the top layer with secondary electrons. However, with dielectric coatings like epoxy, you will need to apply a layer of conductive material on it (e.g. Pt, Au) via sputtering to be able to study the sample in SEM.
hello Maido you are required to analyze a biological sample by SEM. How can you eliminate the differences between the properties of the sample and the physical properties of SEM? thank you. الترجمة
We did that by making a cross-section with FIB and then studying it with SEM. If the pitting goes very deep, then you might as well try mechanical cross-sectioning.
Hello! Studying dielectric samples with SEM is difficult as every time you scan over it during imaging, it charges up - this means that electrons cannot easily escape the studied site, causing the sample to locally heat up and also the locally charged site interferes with the electron beam, causing additional artifacts on the image. So dielectric samples should be covered with a thin layer of metal (e.g. Pt by magnetron sputtering). Another alternative is to use ESEM, which doesn't require samples to be coated with metal.
Heya! SEM has many applications - we try to cover some of them in our video series, where we study a variety of different samples. The link to the playlist is in the description of this video.
Hello and thank you for the question! When you irradiate the sample with a narrow beam of electrons, then you basically know the X and Y coordinates and measure the intensity of the signal (amount of electrons) coming from that location. The intensity can be understood as a Z coordinate, which is essentially a shade of grey, ranging from black to white. Therefore, by scanning row by row across the surface with the beam of electrons, you will get a data that consists of three coordinates and with a computer software you can easily convert it into an image. Note that in this method higher Z value (brighter spot) doesn't really mean its higher but rather it shows that we have a higher yield of electrons from that specific site.
+Jitender Chaurasia Depends on what you want to see. Generally you only need to remove the "dirt" from metal substrates if you want to see the natural surface. If it contains oil leftovers from manufacturing or fat from fingers (mixed with salts), then you need to clean it with deionized water and organic solvents such as acetone. If the substrate is generally clean from such pollution, then a rubber syringe is good enough to remove the loose particles. Generally I wouldnt recommend etching - unless you are studying corrosion or want to remove the natural oxide layer for EDX analysis.
+Rupan Kaur The picture might be more interesting indeed after the etching as the sample would be covered with valleys and craters but generally any pre-treatment and cleaning/refreshing of the sample should be as non-destructive as possible!
Yes. But you will need a transmission electron microscope for that purpose and prepare a very thin sample. In the current video we use a scanning electron microscope, which is cannot see atoms but is great for studying surfaces with a resolution up to 1 nm.
Hello and thank you for the question. It really depends on the substrate and coating as there are lots of methods to choose from. For instance, making cross-sections with focused ion beam and studying them with SEM. Or you can use special tools to cut precise slices of the material and image it from the side with SEM. We will publish a video in the end of march where we study a tooth under the scanning electron microscope - for that purpose we cut it into half as well.
***** Thank you... I am lecturer, I am teaching SEM for Undergrads. if possible to provide this animation it will be very helpful... I will provide due credits to you in my classes. Can you please share this animation ? thanks
![COLOMBIA vs. CHILE [4-0] | RESUMEN | ELIMINATORIAS SUDAMERICANAS | FECHA 10](http://i.ytimg.com/vi/TDjN4W3yy1k/mqdefault.jpg)
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Best video on SEM ever! Thanks
Thank you for the demonstrating.
It is really a clear and easy to understand the scanning electron beam by your method.
Really Thanks.
Hey! Thanks for the feedback. We really appreciate it!
Hi Maido,
This is probably the most helpful video about the SEM I've watched, you're using a modern SEM and you're not making it too complicated, thanks a lot! The only thing that I wish you had shown was the elemental composition analysis because that still confuses me a bit whenever I try it.
One question: how do you decide which accelerating voltage to use for studying a certain specimen, and why is it important?
***** Thank you, that's very helpful! Yeah, the part when the analysis program gives me weird elements for the peaks is what I'm having problems with, but I hope that as I use the SEM more it'll be much easier. Glad to know that I'm not the only one for whom that happens to. Thanks :)
+Maido This is just what i needed. Just got better understanding of SEM-EDX. Thank you
You have a very Excellent way of teaching and your university have a very good lab.
Thanks!
It is a great and very useful video about SEM. Thank you, my friend from Estonia.
Thank you for watching our video!
Finally I got the basic concept atlest .😫. Thanks so much.. 😘
It was the best video which I found for SEM. Would you please also make a video which describes how to prepare a good sample for the test?
Thanks! Actually we have a whole series dedicated to sample preparation as each case requires a unique approach. Here is the link to the videos: ruclips.net/video/fnRnoJigsu0/видео.html
Nice video.
I saw and learned many things.
Thank you.
Great video. Quite illustrative!
Thank you Sir!
Thanks Dr Maido. Sure today I will see you SEM images video.
Very nicely explained
Thank you so much
Thanks! It was one of our first videos and perhaps we might make a more detailed and better one in the future. Learned a few more tricks since then =)
Very nice. Thank you for the details in every step of the process.
Thanks a lot! We might make an updated version of the video at some point in the future as the hardware of our company received a major upgrade, allowing us to make better animations.
Arcanity, the choice of accelerating voltage, or beam energy, is complicated. First, in most SEMs, resolution is better at higher voltages. If you are lucky enough to have a modern field emission system, then you can go to very low voltages at high mags. Besides that, more surface detail is visible at low energies. Also, less damage happens at low energy. Finally, sample charging depends on beam energy. If you play with the accelerating voltage for nonconducting samples, then you might get lucky and find a value for which the primary electron flux balances the secondary and backscattered electron fluxes, and charging can be minimized. That is tricky business. In general, use the lowest energy you can get away with and still have the resolution that you need. Of course, if you do EDX, then you must use certain voltages to get the signal that you are looking for.
Excellent video. I loved it. Only thing missing was EDS.
Thanks for the feedback. You might want to check out our "under the scanning electron microscope" series, where we also use EDS :)
ruclips.net/video/fnRnoJigsu0/видео.html
Hello, it is a nice video.. Am using zeiss EVO 18 floor model and Jeol 6000+ bench top both SEM...But ur Microscope is very nice and costly.. ❤️❤️
Thanks! Please share your opinion on bench top SEM. We were thinking of getting one for the students to play with. The other ones here might be interested in your feedback as well since a bench top SEM is generally obtainable already at a low price.
Nice video presentation and exaplanation
A very useful video. Thank you very much. I have a question: doesn't the electron beam damage the sample ? and how thick can the sample be in order to withstand the electrons ?
Thank you in advance !
Hello and thank you for the question! It really depends on the sample and the beam current. If the beam current is sufficiently high, then it is possible to drill a hole through any material.
In scanning electron microscopy one should use as low beam current as possible when studying substrates that get easily damaged by electrons. Coating the sample with a thin layer of conductive material (Au, Pt) would also help a lot. I remember how I once had NaOH crystals on the substrate and they were destroyed rather fast under the electron beam (barely got 1 image). Conductive carbon nanotubes on the other hand are much easier to study as the charge and heat is quickly carried away. So ideally you can easily study nanoparticles if they are properly prepared (e.g. apply nanopowder on silver paste on a conductive holder).
Captain Corrosion thank you very much once again ! followed it better now.
You are welcome!
Hi. U have a great video here! I have a question. Can SEM analyze the microstructure of a metal surface that is covered with epoxy but with exposed area of 10mm^2 only??
If the surface is covered with epoxy, then you'll see only the top layer with secondary electrons. However, with dielectric coatings like epoxy, you will need to apply a layer of conductive material on it (e.g. Pt, Au) via sputtering to be able to study the sample in SEM.
@@CaptainCorrosion understand sir. Thank you so much! Im studying corrosion on magnesium plate. Wish me luck ☺
@@nurulshahzira769 Good luck!
Great video. Thank you!
This is the Great Thing To US!!! Thank you Scientists!! :) :-)
Captain Corrosion at your service!
Very informative lecture Sir.
hello Maido
you are required to analyze a biological sample by SEM. How can you eliminate the differences between the properties of the sample and the physical properties of SEM? thank you.
الترجمة
how to identify the different composition elements and level of distribution
Can we find out the depth of pitting corrosion by SEM?
We did that by making a cross-section with FIB and then studying it with SEM. If the pitting goes very deep, then you might as well try mechanical cross-sectioning.
Hello In the case of the sample a dielectric material Is irradiated before imaging or not and why
Hello! Studying dielectric samples with SEM is difficult as every time you scan over it during imaging, it charges up - this means that electrons cannot easily escape the studied site, causing the sample to locally heat up and also the locally charged site interferes with the electron beam, causing additional artifacts on the image. So dielectric samples should be covered with a thin layer of metal (e.g. Pt by magnetron sputtering). Another alternative is to use ESEM, which doesn't require samples to be coated with metal.
really thanks for this video
You are welcome! Might make an updated and more detailed version in the future though as Ive got more experience now with this technique.
lovely video
Thank you Mellowgirl!!!
you're welcome
Sir, can tell me the exact application and outcome of the SEM process??
Heya! SEM has many applications - we try to cover some of them in our video series, where we study a variety of different samples. The link to the playlist is in the description of this video.
But how this emitting electrons gives the image? I mean electrons are going into the detector then image? Silly question may be.. 😭 help me.
Hello and thank you for the question! When you irradiate the sample with a narrow beam of electrons, then you basically know the X and Y coordinates and measure the intensity of the signal (amount of electrons) coming from that location. The intensity can be understood as a Z coordinate, which is essentially a shade of grey, ranging from black to white. Therefore, by scanning row by row across the surface with the beam of electrons, you will get a data that consists of three coordinates and with a computer software you can easily convert it into an image. Note that in this method higher Z value (brighter spot) doesn't really mean its higher but rather it shows that we have a higher yield of electrons from that specific site.
Thanks Maido.... it is very informative.
do we need to etch metal samples before doing SEM
+Jitender Chaurasia Yes, the sample should be etched to generate a better picture.
+Jitender Chaurasia Depends on what you want to see. Generally you only need to remove the "dirt" from metal substrates if you want to see the natural surface. If it contains oil leftovers from manufacturing or fat from fingers (mixed with salts), then you need to clean it with deionized water and organic solvents such as acetone. If the substrate is generally clean from such pollution, then a rubber syringe is good enough to remove the loose particles. Generally I wouldnt recommend etching - unless you are studying corrosion or want to remove the natural oxide layer for EDX analysis.
+Rupan Kaur The picture might be more interesting indeed after the etching as the sample would be covered with valleys and craters but generally any pre-treatment and cleaning/refreshing of the sample should be as non-destructive as possible!
Can we see the real atomic structure of metal though electron microscope sir
Yes. But you will need a transmission electron microscope for that purpose and prepare a very thin sample. In the current video we use a scanning electron microscope, which is cannot see atoms but is great for studying surfaces with a resolution up to 1 nm.
@@CaptainCorrosion thank you sir
Great
how can we measure the coating thickness
Hello and thank you for the question. It really depends on the substrate and coating as there are lots of methods to choose from. For instance, making cross-sections with focused ion beam and studying them with SEM. Or you can use special tools to cut precise slices of the material and image it from the side with SEM. We will publish a video in the end of march where we study a tooth under the scanning electron microscope - for that purpose we cut it into half as well.
WOW!!!!
Thanks
can you tell me where can I download this animation ?
***** Thank you... I am lecturer, I am teaching SEM for Undergrads. if possible to provide this animation it will be very helpful... I will provide due credits to you in my classes. Can you please share this animation ? thanks
***** Thank you, I will look into it... very kind of you...