Chapter 319 Mercury Cadmium Telluride, Start
"Okay, let's do this based on our conditions. Director Gao, what is this Vaseline used for?"

"This is used to reduce internal friction during processing. It can be considered a process additive."

The two discussed the plan for a while. Mr. Luo was amazed at Gao Zhendong's ability to "know everything". "Director Gao, you are very familiar with energetic materials."

Gao Zhendong laughed: "I just know a little bit, but it's a pity that the committee won't let me do more, so I can only do this one."

After hearing this, Mr. Luo felt a headache. The committee would definitely not let you do any more of this.

As for the production process of this propellant, it is a combination of more traditional energetic material processes and compression molding. Speaking of this, Mr. Luo understands it better than Gao Zhendong.

The two of them had another discussion about the process, with Gao Zhendong mainly raising requirements and Mr. Luo confirming whether the conditions were met. If not, he would still have to make relevant preparations.

This involves many processes such as absorption, mixing, water driving, calendering, drying and stretching. Gao Zhendong and General Manager Luo communicated and confirmed them one by one. There is quite a lot of content. General Manager Luo also felt a little overwhelmed. Although the processes are the same, the specific process parameters are different.

While communicating with Gao Zhendong about the technology, we were able to learn a lot of extended knowledge related to these technologies. After all, what Gao Zhendong came up with was a little bit advanced, and it could also help the Changjian Factory to learn by analogy, which was very useful.

Although these are all included in the plan, it is equivalent to a technical briefing. Reading the materials is never as comprehensive and direct as personal communication. Otherwise, everyone can just learn by themselves with the textbooks. Why do we need a teacher? The plan only tells you how to do it, but why you should do it this way. You have to communicate with the designer face to face to understand the tricks.

Mr. Luo looked at his notebook which was filled with many pages, and a big smile appeared on his face. It was interesting to work with a capable person like Mr. Gao, where one could achieve results and learn at the same time.

After seeing Mr. Luo off, Gao Zhendong packed up and went home. However, since it was not Children's Day yet, he was not ready to give the Children's Day gift to Lou Xiaoe. If it was Children's Day, then it was Children's Day.
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Yu Yuncheng sat in front of Gao Zhendong, smiling happily. It had taken several weeks from May Day to now to finally finish the work at Institute 1761. This made Yu Yuncheng a little impatient.

After all, knowing that there was a good thing in front of him, he would definitely not be able to resist. However, the single crystal furnace and single crystal silicon were a big deal for the 1761 Institute, which forced him, as the person in charge of the 1761 Institute, to spend a lot of time arranging and handling the affairs within the institute.

After finally dealing with all these matters, he immediately brought a few key members and rushed to the capital.

When the leader of 1761 asked him why he went to Beijing again, Yu Yuncheng said, "Director Gao of the Third Rolling Mill has a new project and wants to continue cooperation. He also said that although they are still the leaders of this project and he will apply for relevant resources, it will not be done in the Third Rolling Mill, but in our institute."

The leader of the 1761 Institute immediately drove them away without saying anything: "Then hurry up and stop hanging around in the institute."

The benefits of the project being implemented in the institute are self-evident.

Now Yu Yuncheng is here with Gao Zhendong, looking for projects.

Gao Zhendong was also very happy to see him, as the matter of mercury cadmium telluride fell on his shoulders.

Although there is still some distance to go before we can prepare mercury cadmium telluride crystals and develop offline thermal imaging cameras, without this first step, the rest is easy.

As for not considering indium antimonide, the main reason is that the bandgap characteristics of mercury cadmium telluride can be changed by adjusting the composition and doping. In layman's terms, mercury cadmium telluride has good photoelectric properties in multiple bands such as near-infrared, mid-infrared and far-infrared.

Moreover, this thing has good anti-radiation performance. To put it bluntly, it can be used in outer space or in nuclear environments.

Although the preparation of mercury cadmium telluride is relatively difficult, indium antimonide is not much better these days. It's troublesome anyway, so why not try mercury cadmium telluride first? Gao Zhendong has a whole article dedicated to the preparation of mercury cadmium telluride crystals.

Looking at him, Gao Zhendong smiled and said, "Old Yu, you are finally done."

Yu Yuncheng smiled embarrassedly: "There are a lot of finishing tasks for the single crystal furnace in the institute, so there was a little delay."

Gao Zhendong shook his head: "For such a big thing, it's normal to have more related matters. It won't be a problem, it won't be a problem."

Yu Yuncheng smiled and said, "It's been dealt with anyway. Director Gao, what are you going to do this time? I have already kept some people here and informed the institute. They will fully cooperate."

Gao Zhendong nodded: "Let's make mercury cadmium telluride crystals!"

Yu Yuncheng was stunned when he heard this. To be honest, he didn't know what mercury cadmium telluride was. This thing was only invented in 1959. At that time, basically no one in China knew what it was. "Mercury cadmium telluride? What is it?" He was not even sure whether it was mercury cadmium telluride or mercury chromium telluride.

Gao Zhendong took a pen and paper and wrote down the chemical formula HgCdTe, which is not really a chemical formula, on the paper. Only then could Yu Yuncheng confirm what Gao Zhendong was talking about, but he still had no idea what this thing was used for.

Gao Zhendong continued to introduce the properties of mercury cadmium telluride materials. Yu Yuncheng became more and more excited as he listened. This is a very good optoelectronic semiconductor material, and it has a wide band coverage and stable performance structure. It will be really interesting to make this thing.

But he was a little afraid, as he knew absolutely nothing about this.

"Director Gao, this thing is good, but can we make it?"

Gao Zhendong smiled and nodded: "I still have some confidence. I have explored a preparation method based on its structure, properties, components and other principles, from the perspectives of metallurgy and crystal phase. I still have some confidence. At least I will have no problem getting the compound first. As for high-quality crystals, I also have some confidence."

Gao Zhendong's words made Yu Yuncheng's hair stand on end. Are you just calculating and deduce from the principle? Where does the principle come from? If you hadn't told us that there is such a thing, none of us would have thought that there is such a thing. Infrared detection is still competing with lead sulfide. How do you calculate it?

However, he knew that Gao Zhendong never talked nonsense. From the beginning, it seemed that the conditions for making a single crystal furnace were not met. But the facts were there. Now, raw materials were being supplied to Factory 1274 every day, and at the same time, single crystal furnaces were being produced non-stop to expand production capacity.

What he could not have imagined was that Gao Zhendong not only knew about this thing, but he also had a series of data and results from decades later, including its lattice constant, density, Te-Cd-Hg ternary phase diagram, HgTe-CdTe pseudo-binary phase diagram, relatively accurate segregation coefficient, thermal properties, mercury vapor pressure, electrical properties, etc.

Let’s put it this way, even the inventor of HgCdTe in 1959 did not have as complete and accurate information as Gao Zhendong has.

Although he didn't know where Gao Zhendong's confidence came from, he was not a fool. Director Gao had no need to joke with him, so he didn't hesitate: "Director Gao, I'll do whatever you say."

Gao Zhendong smiled and said, "Okay, but you have to be mentally prepared. This is not something that can be done in a day or two. The whole process is very long. One experiment may take several months or even half a year to complete."

Due to mercury vapor pressure and other reasons, it is very difficult to grow crystals of mercury cadmium telluride, whether it is bulk crystals or thin film crystals. Although there are many methods, they are all quite troublesome. Not only is the crystal growth slow, but the annealing and other processes are demanding and time-consuming, and it can take dozens of days at a time.

This makes the entire experiment time-consuming and it is impossible to complete it without determination and perseverance.

Yu Yuncheng doesn't care about this. It doesn't matter if it takes longer. Besides, Director Gao may have a broad vision because of his high level.

In Yu Yuncheng's opinion, conducting an experiment once every six months is not a problem. For this kind of thing, let alone producing crystals, even if they can produce the compounds first and confirm something, it will be a major breakthrough.

So, although working with Director Gao brings great achievements, the pressure is also great.

"Director Gao, don't worry about this. We can still endure loneliness."

Gao Zhendong nodded. In fact, they didn't have to worry too much. Gao Zhendong was very particular about the choice of preparation method. He chose a method with the simplest process, the lowest equipment requirements, and low temperature control requirements. Most importantly, it did not require a crystal growth control mechanism, which was the most troublesome thing.

It just so happens that the crystals grown by this method have uniform composition and good structure. They can be used in the production of detector-level components, and the crystal utilization rate is very high.

Of course, this thing is not without its shortcomings, such as small crystal diameter, many high-temperature defects, unpurified impurities, etc., but these are not problems at this stage.

The crystal has a small diameter. I'm doing line scanning, so I just want to make it longer. I don't need a circular plane.

As for why Gao Zhendong quickly chose this method, the reason is quite simple. This thing was the main crystal growth method for the mass production of mercury cadmium telluride detection elements in the United States in the next few decades.

I have to say that in this regard, Citi Select is still trustworthy.

However, it is not the time to come up with all the methods at this time. The first priority now is to get the project approved.

Seeing that Yu Yuncheng did not hesitate, Gao Zhendong did not drag his feet and immediately handed him some materials: "That's fine. You first write a research application based on these materials, and we will submit it to the Ministry. According to the pre-agreed agreement, our two units will work together, with the Third Rolling Mill taking the lead and the 1761 Institute implementing it. As for the specific methods, you don't need to write them down. The Ministry should understand."

(End of this chapter)