Chapter 221 Completely Impressed!

As early as his sophomore and junior years, Yuan Shuai and Yang Yan participated in an innovation experiment for college students. The scientific research value of that experiment was higher than that of a normal undergraduate graduation project majoring in materials.

Coupled with what Yuan Shuai learned during his internship in the laboratory during this period, Ning Chen felt that Yuan Shuai's current ability was no worse than when he first entered Xuzhou Laboratory.

After explaining the experimental idea clearly to the original commander, the two officially started the experiment.

At the beginning, Ning Chen did not intend to give him any complicated tasks. He just asked him to do some relatively simple tasks so that he could become familiar with the various operations of the experiment.

Ning Chen was also very satisfied with the performance of the former commander. He could firmly remember all the details that Ning Chen gave to the former commander and completed the work of the experimental assistant almost perfectly.

After Sui Feng came to the laboratory and saw Ning Chen and Yuan Shuai doing experiments together, he couldn't help but ask:

"You...are you starting research on a new topic?"

"Well, although I haven't applied for the project yet, I want to do a few sets of experiments in advance."

This kind of experiment is generally called a "pre-experiment". It can explore the ideal conditions for some experiments in advance and save valuable time for subsequent formal experiments.

This is also some of the routine operations used by Ning Chen and Xu Zhou in scientific research projects. If each subject waits for formal approval before starting experiments, in the long run, the progress of scientific research will be greatly different.

"No, Teacher Ning, I remember you have just returned to school for two days. Isn't your speed of starting this new subject too fast?"

Ning Chenxin said that he may not necessarily have to go to the Chinese Academy of Sciences again one day, and he must race against time for experiments.

"Well, I just applied for the project, and then I started experimenting first. Sui Feng, do you want to consider joining this project?"

Ning Chen also knew that Sui Feng probably didn't want to participate in his project this time, but he still asked politely.

"I won't join in. Let's give Junior Brother Yuan Shuai more opportunities this time. Junior Brother Yuan Shuai, do scientific research well with Teacher Ning. Papers are indispensable. The last project we did together, we published one It’s a sub-journal of Nature.”

The reason why Sui Feng didn't want to do experiments with Ning Chen this time was because Sui Feng needed the results of his first work more now.

If he were to work on a project with Ning Chen, Sui Feng could only get a second-authored paper at most, which would still be much less helpful for graduation and subsequent employment than a first-authored article, even if the papers and journals published by the first-authored article were not that outstanding.

But it is completely different for Yuan Shuai. Now Yuan Shuai has just entered the first year of graduate school. It is the time to accumulate experience. Being able to do experiments with Ning Chen is undoubtedly a very valuable opportunity.

If I could publish a paper with Ning Chen, even if it was only two or three papers, it would be an accumulation of achievements.

"Senior Brother Sui, I will definitely conduct experiments with Teacher Ning." Marshal Yuan promised seriously.

Ning Chen was not used to the former commander's overly formal attitude.

"Okay, if nothing happens, let's continue the experiment." Ning Chen said.

Sui Feng also knew what was going on and didn't bother Ning Chen and Yuan Shuai anymore, and started preparing his own experiment.

…

After a period of preliminary experiments, Ning Chen and Yuan Shuai have almost figured out the best conditions for some experiments.

The former commander's progress is also very rapid. Not only can he complete his tasks well, he is also very active in learning knowledge beyond his responsibilities.

This made Ning Chen feel relieved to hand over more tasks to the former commander, so that the former commander could take on some more important tasks in the experiment.

What Ning Chen didn't know was that after returning to the dormitory every day, the former commander would summarize and analyze what he learned every day, and set some short-term goals for himself.

The former commander knew that he did not have Ning Chen's talent, but he still regarded Ning Chen as his goal, hoping that he could devote himself to scientific research like Ning Chen.

With the application for this project officially approved, Ning Chen and Yuan Shuai can finally start the formal experiment.

"Commander, let's clean the surfaces of these single crystal silicon wafers first."

"Okay, I'm going to clean it up."

What Ning Chen calls "cleaning the monocrystalline silicon wafer" is not simply washing with water, but requires multiple cleanings with trichlorethylene, acetone, methanol, etc. to remove dirt and oxidation on the surface of the monocrystalline silicon wafer. substances, impurities, etc.

This step does not seem complicated, but the operation process must be very precise to ensure that subsequent experiments can proceed smoothly.

After completing the cleaning process of the single crystal silicon wafer, Ning Chen even needed to observe the state of the surface of the single crystal silicon through an electron microscope before he could decide whether to continue the next experiment.

After carefully checking the surface condition of the single crystal silicon wafer, Ning Chen was very satisfied with Yuan Shuai's experimental work.

"Very good, the surface condition of this single crystal silicon wafer is already close to perfect." Ning Chen said with admiration.

Even Ning Chen himself would be hard-pressed to clean monocrystalline silicon wafers better than Yuan Shuai.

Although this is just a small step in the experimental process, any complex research is accumulated from such small steps.

The former commander was not proud of Ning Chen's praise. He continued to maintain a serious state and prepared for subsequent experiments.

After preparing the cleaned single crystal silicon wafer, Ning Chen and Yuan Shuai placed the single crystal silicon wafer in the vacuum chamber.

During the femtosecond laser processing of single crystal silicon wafers, it is also necessary to prevent the single crystal silicon from being oxidized, so the experimental environment must be strictly isolated from oxygen.

Of course, due to the influence of various comprehensive conditions, a complete vacuum environment may not be the best choice for experimental conditions.

"Commander Yuan, next we need to conduct experiments in several working environments. The first is a complete vacuum environment, the second is to add part of the working gas to the vacuum background, and the third is to perform experiments on a single crystal silicon wafer. Apply some solid powder to the surface..."

Ning Chen's requirements for scientific research were extremely strict. Ning Chen wanted to try all possible experimental conditions.

Commander Yuan will not feel tired because of too much experimental workload. Before this, Commander Yuan has been mentally prepared and is familiar with each experimental condition.

In this way, Ning Chen and Yuan Shuai conducted experiments for more than ten days in a row, and finally completed all the experimental conditions from scratch.

During this period, due to class reasons, Yuan Shuai could not stay in the laboratory all the time and could only use his spare time to come to the laboratory.

Even so, Yuan Shuai spent a lot of time in the laboratory every day, and even during his lunch break, he spent all his time on this experiment.

The preparation of samples is not all the experimental work. Next, Ning Chen and Yuan Shuai worked together on various measurements of the samples.

During the sample measurement process, Ning Chen would also patiently explain to Yuan Shuai how to use various instruments, and try to let Yuan Shuai conduct more experiments with his own hands.

After many days of continuous measurement work, Ning Chen and Yuan Shuai finally completed the measurement of all samples and analyzed the data together.

Ning Chen did not rush to express his conclusion, but let the former commander talk about his thoughts first.

After some observation and comparison, Yuan Shuai said:

"First of all, we can clearly find that after femtosecond laser irradiation, a more regularly arranged array of tiny conical structures appears on the originally smooth crystalline silicon surface, and the tops of these conical structures are not in contact with the surrounding silicon surfaces that have not been irradiated. Pretty much in the same plane.”

Marshal Yuan observed very carefully. Except for some obvious features, all kinds of details did not escape Marshal Yuan's eyes.

"Then we can see that the cone-shaped structure formed in the air is the roughest, and the surface is also covered with a layer of finer, dendritic nanostructures with a length of tens of nanometers. Under other conditions, these The conical structure is more compact and has no obvious relationship with the composition of the working gas..."

After listening to the former commander's analysis, Ning Chen also nodded happily.

There are basically no major problems in the content of Yuan Shuai's analysis. Of course, there are still some areas that Yuan Shuai did not analyze immediately.

"Commander, what you said is very good. It basically summarizes some main phenomena and patterns. Here I will add some other questions."

After hearing Ning Chen's words, the former commander also looked attentive and waited for Ning Chen's explanation.

"Commander, if you look carefully at the bottom of the conical structure in these images, do you find any problems?"

Under Ning Chen's guidance, the former commander gradually found the problem.

"Ning Chen, the bottoms of these conical structures... seem to be asymmetrical!"

Ning Chen also nodded when he heard this and said:

"Yes, the bases of these conical structures are indeed asymmetric, and their short axes are parallel to the polarization direction of the laser. In addition, through comparison, we can also conclude that as the laser flux increases, and As the number of pulses increases, the cone-shaped structure formed will be taller and larger, and the spacing will be wider..."

Ning Chen talked about several problems he had discovered, which the former commander had not noticed before.

After listening to Ning Chen's story, the former commander became even more impressed by Ning Chen's ability.

The former commander had obviously observed these inspection images and measurement data very carefully, but he still could not fully notice the details discovered by Ning Chen.

The gap between himself and Ning Chen is really wider than the original commander expected.

Although Ning Chen is now a researcher at Shengzhou University, the former commander also knows that four years ago, the two of them were at the same starting point.

Even if he just wants to catch up with Ning Chen's shadow, the former commander still needs to put in more effort than he does now.