Half an hour was not long. While Xu Chuan was observing the lunar rock material through a scanning electron microscope, the testing on the other side of the laboratory was also successfully completed.
The detection results of lunar rocks using ultra-high-resolution field emission scanning electron microscopy have been drawn into data tables and pictures.
After connecting the color printer and image printing equipment, Wang Hang, who was responsible for conducting the experiment, quickly printed out the relevant data charts.
"Academician Xu, Institute Zhao, the analysis results of the field emission scanning electron microscope have come out."
Taking the experimental data from the other party, Xu Chuan quickly read through it.
Compared with conventional scanning electron microscopy, ultra-high-resolution field emission scanning electron microscopy takes much longer.
But it can also see a lot more things.
In particular, the equipment in Xinghai Research Institute uses the latest digital image processing technology to provide the latest level of high-magnification and high-resolution scanning images. It is valuable and can also bring more observations of the material itself.
Generally speaking, the scans of the lunar rocks in the Yaochi crater are almost the same as those observed with ordinary electron microscopes.
But the details are completely different.
For example, the SED image of an ordinary scanning electron microscope can visually display the thickness of carbon nanotubes and the interweaving state between carbon nanotubes.
However, in the field emission scanning electron microscope STEM image, you can see the small particle structure hidden in the 3D structure.
These particle structures cannot be seen in traditional scanning electron microscopy experiments.
In addition, field emission scanning electron microscopes also have unique brightfield image BF, darkfield image DF, and high-angle annular darkfield image HAADF modes, etc.
These images have different imaging advantages and can be used together according to the sample conditions, and the imaging results can be verified with each other.
Xu Chuan discovered something special in the high-angle annular dark field image HAADF of the lunar rock in the Yaochi crater.
"It's a bit interesting. The trajectory and intensity of the secondary electrons of these carbon nanotubes in HAADF imaging have obvious differences between light and dark compared to light and dark field imaging."
After muttering something in his mouth, his eyes fell on a drawing in his hand, with a hint of thoughtfulness in his eyes.
When placed on a 1,000,000X magnification image, there is a clear difference in the brightness of the regular and neat carbon nanotubes.
There are some obvious changes in the energy response, composition contrast, and morphology contrast data of HAADF imaging.
On the side, Zhao Guanggui frowned slightly and said: "This shouldn't be the case. Theoretically, HAADF imaging and BF and DF imaging will not have such a large difference in contrast and energy response."
Although the three imaging methods are different and the images formed will be different, it is rare for the energy and contrast to be so different.
Xu Chuan smiled and said: "It's not impossible. If these carbon nanotubes are doped with the underlying substrate, resulting in a structure similar to the semiconductor gates in integrated chips, these differences can be explained.
"
Hearing this, Zhao Guanggui looked over in surprise and couldn't help but ask: "Are you saying that if there are differences in potential distribution on the surface of these samples, such as P-N junctions similar to semiconductors, biased integrated circuits, etc., what will happen to them?"
The difference in local potential affects the trajectory and intensity of the secondary electrons."
Xu Chuan nodded and said: "Well, at present, this guess is most likely to explain this energy and contrast gap."
"Hiss~"
Zhao Guanggui took a breath and said in surprise: "If so, this is most likely a natural carbon nanotube integrated board?"
Staring at the experimental data report document in his hand, Xu Chuan pondered and said, "I don't deny this possibility, but the possibility that it is a natural carbon nanotube integrated circuit board is still very low in my opinion."
"Um?"
Hearing this, Zhao Guanggui and the other two researchers in the laboratory all looked at him with surprise and confusion.
According to the data on HAADF imaging, this is a very obvious potential contrast difference, and generally speaking, this difference usually only appears on semiconductors.
Because semiconductors have local potential differences, in the positive potential area, the secondary electrons seem to be pulled and difficult to escape. Therefore, in these areas, the secondary electron yield is less and the image appears darker;
On the contrary, in the negative potential area, secondary electrons are easily pushed out, the yield is higher, and they appear brighter on the image. This is the potential contrast.
Generally speaking, the analysis of semiconductor equipment from other countries, such as chips, is done through potential contrast.
(This is a structural diagram of a chip electron microscope, you can clearly see the differences inside)
Looking at the experimental report in his hand, Xu Chuan thought for a moment and explained: "Although judging from the scanned image, when the bias voltage is applied, the substrate has semiconductor properties to a certain extent."
"But there is still a big gap between it and carbon-based integrated tubes. From a material science point of view, I personally prefer that it is affected by external forces and is doped with some other materials, resulting in a difference in resistance.
."
"Looking at the third picture, you can clearly see that the carbon nanotubes in the third column have different molecular brightnesses."
After a slight pause, he continued: "But this direction can be studied to see what elements it is doped with. It would be good to learn from it."
Zhao Guanggui's eyes moved, he stared at the experimental data in his hand and said, "You mean the doping research on carbon semiconductors?"
Xu Chuan nodded and said with a smile: "Well, although carbon and silicon have similar properties, they are still very different."
"Carbon is a conductor, and silicon itself is a semiconductor, so it is very difficult to dope it perfectly and convert it into a stable carbon semiconductor."
"But now, the moon is pointing us in a direction."
"Although the carbon nanotubes in this material are not integrated with carbon transistors, they are doped with other elements."
This chapter is not over yet, please click on the next page to continue reading! "Test what elements are involved in these carbon nanotubes, and then replicate them with high-purity carbon materials to see how they perform in all aspects."
"Perhaps it can also help us solve another problem of carbon-based chips."
Zhao Guanggui nodded and said: "I will arrange for someone to conduct experiments in this area!"
It is not a rare thing to obtain research ideas and inspiration from natural materials or creatures in nature.
For example, geckos and robotic claws, shark skin and ship coatings, swimsuits, maple seeds and drones, etc.
And the moon rock in front of them can also give them some very good inspiration.
The first is the neatly and tightly arranged carbon nanotubes, which is the most important discovery.
It is of extremely high value for them to study how carbon-based chips can efficiently integrate carbon transistors.
The second is the microstructure now discovered through field emission scanning electron microscopy.
These carbon nanotubes existing in lunar rocks have obvious doping phenomena. This may be caused by changes in external temperature, pressure and other conditions.
This is also important for their study of how carbon nanotubes can create semiconductor switches with excellent performance.
In fact, the problem with carbon-based chips is not just the arrangement of carbon-based pipes.
Even though it's the hardest part, that doesn't mean there aren't other challenges.
For example, carbon is a conductor and has electrical conductivity. Whether it is pure carbon or impure carbon, it can conduct electricity.
Controlling the defect-free structure of nanocarbon materials, converting them into semiconductors, and controlling the purity of semiconductors have also become extremely difficult problems.
To be precise, carbon is more difficult to apply in semiconductors than silicon and has more disadvantages.
In fact, it has to be said that silicon material is the best, or most suitable, material that humans can currently find in the chip field.
The overall performance and adaptability of carbon, based on current technology, are far inferior to silicon materials in terms of chips.
The talents cultivated by top semiconductor companies such as Intel, Applied Materials, Lamb Research Institute, Dongjing Electronics, etc. are not idiots.
It is no exaggeration to say that most of the time, whether it is academia or major research institutes, whether it is an idea that comes up in the head or a flash of inspiration, these companies actually started as early as two or three years ago.
It was pre-researched ten years ago.
Then we will give up decisively because of this idea, some irreparable flaw in this material, or too high research difficulty.
For things like chips, no matter how much other performance is said, if one key indicator is not good, it will be killed directly.
Germanium, for example, is an example.
Germanium crystals have self-strain and are prone to thermal and cold drift, which deteriorates the stability of the chip.
This was enough to cause germanium to be abandoned on a large scale by the industry after the emergence of silicon.
The development of silicon-based chips to the current stage is the optimal solution that has been compromised by countless attempts in the industry for decades.
At least it is the optimal solution at the current stage of technological development.
In this regard, the overall performance and evaluation of carbon cannot catch up with silicon.
Of course, this does not mean that carbon has no future.
On the contrary, carbon-based chips have far greater prospects than silicon-based chips.
Higher integration, faster computing speed, not affected by quantum effects...low energy consumption, low heat dissipation, high electron mobility, more suitable for high-frequency and overclocking operations than silicon-based chips, etc.
These are the advantages of carbon-based chips.
To be continued...