Xueba starts with change

Chapter 245 Shake people to help (add 3 for Ali)

Just when Shen Jing was filled with emotion, Chen Zhou came back.

There was also a tall, thin boy with glasses.

"Senior, let me introduce you." Chen Zhou pointed to the boy beside him, and introduced, "This is Zhang Yifan, my deskmate in high school, from the Chemistry Department of Huaguo University of Science and Technology. I called him to help."

After finishing speaking, Chen Zhou pointed to Shen Jing again: "This is the senior Shen Jing who came to Luzhou with me this time to participate in the project. Like me, he is from the Department of Mathematics of Yanda University."

"Hello." Zhang Yifan and Shen Jing greeted each other.

"Yifan, you come here." Chen Zhou moved the chair and put it beside the table, and then said, "For the documents you downloaded in the afternoon, delete the first 47 articles, and the specific technical materials in the latter documents are just It's up to you to help me sort it out."

"No problem." Zhang Yifan nodded, but then thought something was wrong. If you remove 47 articles, there are still...

???

Chen Zhou looked at Zhang Yifan with a smile and said, "I believe you can do it!"

Zhang Yifan: "..."

Shen Jing looked at Zhang Yifan, then moved closer to Chen Zhou, and asked softly, "When did you ask him to download the documents for you?"

Chen Zhou said: "Before I went to Dr. Wu's office, I called him and asked him to help find documents. After all, some documents can only be downloaded in the school library."

Shen Jing was stunned, and then took a deep look at Chen Zhou.

Hearing what the two said, Zhang Yifan smiled and said, "I thought it was something that Chen Zhou called me suddenly, but it turned out that he asked me to help check the documents. I said that you came to Luzhou this time, why didn't you call in advance? How about hello?"

Chen Zhou said with a smile: "Didn't I just arrive? Isn't it interesting to find you right after I arrive?"

Zhang Yifan was noncommittal. He estimated that if it wasn't for the need to check the literature, Chen Zhou would probably call to talk about it before he left.

But he also understands that this is not a vacation, but a mission.

And judging from this posture, it should be a relatively tight task.

So after receiving the call, Zhang Yifan didn't say a word, and spent an afternoon helping Chen Zhou check the documents.

What puzzled him was that Chen Zhou actually wanted so many documents...

Isn't it better to have more of this thing?

"I heard that you are going abroad to give an academic report?" Zhang Yifan asked Chen Zhou thinking of the news he had read on the Internet.

Chen Zhou sat back at the table, flipped through the literature, and said, "Well, on the 15th of next month, I will make a report on the proof of the hail conjecture."

"It's okay, I thought the news on the Internet was unreliable, but I didn't expect it to be true!" Zhang Yifan was very happy for Chen Zhou.

Chen Zhou smiled and urged, "Hurry up and work, and treat you to a big meal later! You have to go back to school at night, so it can't be too late."

"Deal!" Zhang Yifan laughed.

Immediately, the two stopped talking and were busy with their work.

Shen Jing couldn't help but glanced at the two of them. Chen Zhou and Zhang Yifan were looking at the documents seriously, not like they were talking and laughing just now.

"Isn't it too fast to enter the state?" Shen Jing muttered to himself.

What he didn't know was that Zhang Yifan's study habits were basically the result of sitting next to Chen Zhou when he was repeating high school, and was suppressed by that pressure.

Not only Zhang Yifan, but the students around Chen Zhou were more or less affected by it.

While Chen Zhou was changing, they were also changing silently.

Chen Zhou handed over the main finishing tasks to Zhang Yifan and Shen Jing respectively, which also gave him time to study more about the entire preparation process of the diamond film.

Preparation methods can only be improved if they are fully understood.

Moreover, Chen Zhou did not intend to study the MPCVD method from the very beginning.

He intends to be more comprehensive first, and then seek a breakthrough.

There is a change in the method of preparing diamond thin films.

From the high temperature and high pressure in the 50s, to the CVD method first used by Japanese scientists in the early 80s, to today's various synthesis methods.

It is said to be a variety of synthesis methods, but in fact they are all based on the CVD method and improved.

[Preparation of diamond film by hot wire CVD (HFCVD)]

This document has a comprehensive introduction to the preparation of diamond films by HFCVD.

Although this method is the originator of the CVD method, it is still widely used and has developed into one of the more mature methods for depositing diamond films.

This method requires a metal heating wire, such as tungsten wire and tantalum wire, to be placed above the substrate.

Then the carbon-containing gas is heated to 2000~2200°C to decompose and form active particles.

Under the action of hydrogen atoms, it will be deposited on the substrate to form diamond.

Although this method is simple, the deposition efficiency is very low, which is much lower than the method currently used in 43.

Not only that, but the process stability is poor and it is easy to cause pollution.

Although there are two improved methods mentioned in the literature, Chen Zhou also disagrees.

Because the efficiency is improved, but the quality of the diamond film is still too low.

It is obviously not applicable to the research of diamond semiconductor materials and devices.

However, Chen Zhou felt that he could try the improved method.

One is the HFCVD method of reactive gas distribution, that is, the carbon source gas and hydrogen gas are respectively fed from the bottom and top of the hot wire.

The other is the electron-assisted HFCVD method, which increases the deposition rate by applying a bias voltage of about 150V to the substrate.

Chen Zhou reads documents very quickly. Even if he is reading and memorizing while reading, his efficiency far exceeds that of others.

This is also due to the bonus provided by his system discipline upgrade.

Before coming, he quietly upgraded the chemistry to Lv2, just in case.

Therefore, with the addition of the chemistry subject level, Chen Zhou frantically absorbed the relevant chemistry knowledge.

Unlike studying mathematics and physics, Chen Zhou does not intend to use the same method to study chemistry and biology.

Chemistry and biology are two subjects that are more inclined to experiments and applications. Chen Zhou intends to start with experiments and applications.

With the help of the addition of subject level, learn efficiently and find the unknown from experiments and applications.

Then check the information to make up for the unknown.

Although there is no system of mathematics and physics in this way, the efficiency is very high.

And it is very suitable for Chen Zhou now.

After reading three articles on the HFCVD method, Chen Zhou felt that the general ideas were similar, so he stopped entangled with this method.

Instead, he looked at the next method, Flame Deposition.

This method was first proposed by Japanese scholars, but it was confirmed in a laboratory on the other side of the Atlantic.

This method is mainly to mix carbon source gas with oxygen and burn it in the atmosphere.

The burning flame is divided into three zones. In addition to the inner flame and outer flame, there is also a layer of reducing flame.

The substrate is placed in the reducing flame area of ​​the flame to generate diamonds.

The key to this method is the mixing ratio R of acetylene and oxygen.

Only in the R=0.7~1.0 region can diamond be grown.

Other regions are not conducive to diamond growth.

"R=0.97~1.0."

Chen Zhou frowned slightly and looked at the written range.

He saw from the literature that when R = 0.97 ~ 1.0, this method can prepare a transparent optical grade diamond film.

Habitually tapping on the draft paper with a pen, Chen Zhou temporarily skipped this message and continued to read the documents.

[The advantage of this method is that the equipment is simple, the cost is low, diamond can be synthesized in the atmosphere, and the growth rate is fast (60-150um/h), which is beneficial to the deposition of diamond on the surface of large-area and complex-shaped samples. 】

[The disadvantages are: the deposited diamond film has an uneven microstructure, and the film often contains impurities such as non-diamond carbon. Due to the thermal gradient of the flame, the substrate is easily bent and deformed, and a large heat is generated in the film. stress. 】

"A method with obvious advantages and disadvantages." Chen Zhou commented.

(End of this chapter)