Xueba starts with change

Chapter 249

Shen Jing turned his head to communicate with Dr. Wu in a low voice.

Chen Zhou turned his attention to the experimental device.

Just now, Dr. Wu's words reminded him.

In diamond doping experiments, the carrier concentration will affect the Hall mobility.

The Hall mobility directly reflects the degree of boron doping in diamond.

In addition, the doping of boron is achieved by adding boron source to the reaction chamber for preparing the diamond film by MPCVD to realize the boron doping of diamond.

For the boron source, boron-containing gases are generally used, such as B2H6 and B(CH3)3.

When the doping concentration of boron is high, the prepared diamond doping contains many point defects, line defects and surface defects.

These defects can trap carriers and affect the Hall mobility of the diamond material, which in turn affects the prepared boron-doped diamond.

"Sure enough, both the preparation of the diamond film itself and the preparation of single crystal diamond under the doping experiment are contradictory experiments..." Chen Zhou thought to himself.

After thinking about it, Chen Zhou talked to Dr. Wu and went to the n-type doping experiment.

As Dr. Wu said, n-type doping is much more difficult than p-type doping.

For p-type doping, it is also possible to refer to this natural sample.

However, n-type doping can only be explored continuously.

Speaking of it, the n-type doped phosphorus element was explored step by step from nitrogen, sulfur, and lithium elements.

The covalent bond radius of phosphorus is 1.4 times that of carbon, and the energy level is located 0.58 MeV below the bottom of the conduction band.

Because of these properties, phosphorus can form shallow energy levels in diamond films, so it is an ideal element for n-type doping of diamond.

However, the carrier mobility of n-type phosphorus doped diamond is still much lower than that of p-type boron doped diamond.

Chen Zhou found Peng Fei and asked softly, "How is the experiment going?"

Peng Fei pointed to the experimental device in progress: "It's not bad, it's not much different from the previous few times."

After a pause, he looked at Chen Zhou, smiled and said, "It depends on the results of your data processing."

Hearing this, Chen Zhou smiled: "We will try our best."

Peng Fei said again: "If you need help, just ask."

Chen Zhou nodded: "Don't worry, I won't be polite."

After speaking, the two smiled at each other.

Compared with the others, Peng Fei, who was arranged to pick them up at the high-speed rail station from the very beginning, made Chen Zhou feel much more comfortable.

After thinking about it, Chen Zhou asked, "What is the doping concentration of phosphorus in diamond now?"

Peng Fei did not answer directly, but said: "Because the doping concentration of phosphorus directly affects the carrier mobility, when the carrier concentration is low, the impact of ionized impurities scattering is less, and the mobility is higher."

"In 2012, Dr. P et al. increased the room temperature carrier mobility to 100 cm/(V s) by reducing the doping concentration of phosphorus in (780) crystal facet diamond."

“所以，我们在他们的基础上，进一步降低了磷的掺杂浓度。这10组实验磷的掺杂浓度，是在4×10^15/cm~2×10^15/cm区间内依次选取的。”

Chen Zhou nodded, and the 10 experiments were compared with each other.

Chen Zhou remembered one more thing, and asked, "Tomorrow's co-doping experiment is also carried out by your side, right?"

Peng Fei replied: "That's right. The co-doping experiment is actually n-type doping. However, no matter whether we use the MPCVD method for doping during the growth process or the ion implantation method, we use a single element to remove It is still difficult to achieve n-type doping of diamond."

"But it is much easier to achieve n-type conductivity of diamond by doping two or more elements into diamond."

After a pause, Peng Fei continued: "In the n-type doping of a single element, nitrogen and sulfur elements are not suitable options. But in co-doping, co-doping of boron and nitrogen, co-doping of boron and sulfur , and the co-doping of phosphorus and nitrogen can achieve the conductivity of diamond.”

After listening to Peng Fei's words, Chen Zhou turned to ask: "This subject is mainly the research on the preparation of diamond and diamond semiconductor materials. What about the research on properties?"

Peng Fei pointed to Dr. Wu in the distance, and said, "Dr. Wu's other research group is responsible for studying the properties and applications of diamond semiconductor materials."

After finishing speaking, Peng Fei glanced at Chen Zhou, and said with a soft smile, "What? Are you interested in the properties and applications of diamond semiconductor materials?"

"Somewhat interested." Chen Zhou didn't deny it, and instead told Peng Fei about the experimental diode in the particle accelerator.

After Peng Fei listened, he looked at Chen Zhou in surprise: "I didn't expect that you have already participated in such a physics project?"

Chen Zhou replied: "This is the subject of Dean Yang of the Institute of Physics and Technology, and I will be in charge of the data processing part."

Although Chen Zhou said it simply, Peng Fei heard a different meaning.

Nuclear physics research can be attributed to high energy physics. In Huaguo, it is basically a project of the State Key Laboratory.

Chen Zhou has already participated in such a subject project, and I have to say, it is very powerful.

Peng Fei thought for a while, and then said: "If you are interested, you can talk to Dr. Wu. After this project is solved, you can join the next project. Moreover, the 38th Institute of Huake Group is currently conducting research on dilute magnetic semiconductors. , This thing has a wide range of applications in nuclear physics.”

Chen Zhou said softly: "Let's forget it, I haven't even prepared the academic report for going to America next month."

Peng Fei smiled: "That's right, I almost forgot that you are into mathematics. Speaking of which, this is an international academic exchange conference, I'm envious..."

Chen Zhou also smiled, and the two stopped talking, and focused on the experimental device.

The time required for the two groups of experiments is not short. In one morning, it can only be said that the experiment is only halfway through.

Chen Zhou and Shen Jing, who had been in the laboratory all morning, had a discussion during lunch.

Half a day in the morning had allowed the two of them to fully understand the mechanism of the experiment.

Especially Shen Jing, through communicating with Dr. Wu, his understanding of this experiment is no less than that of Chen Zhou.

Of course, only for now.

In two days, whether this guy will forget, only he knows.

In the afternoon, if the two of them stayed in the laboratory for half a day, it would not be very meaningful.

Therefore, Chen Zhou and Shen Jing discussed, first seek Dr. Wu to get the experimental data, and start the specific data analysis work.

To their surprise, Peng Fei brought them to Dr. Wu's office after they finished their meal.

Dr. Wu was working on the computer. When she saw a few people coming in, she said directly: "I guess you are bored in the laboratory. I have already sorted out the experimental data just now, and you can analyze the data in the afternoon."

"There are also some preliminary processing of the data, which you can refer to."

Chen Zhou and Shen Jing looked at each other, Dr. Wu understands too much, right?
But then Chen Zhou thought of something, and couldn't help muttering in his heart: "Could it be Dr. Wu who processed the data? It's so embarrassing..."

Dr. Wu added: "However, because the subject is classified, you can only use the computers in the office for office work, and you cannot take them back to the hotel."

Chen Zhou and Shen Jing nodded at the same time, expressing their understanding.

After all, it is a subject of Huake Group. If it is not confidential, it will make the two even more surprised.

A small office with two computers.

It happened that Chen Zhou and Shen Jing were on the same table.

The afternoon time for the two of them is here.

Shen Jing turned on the computer, clicked on the data casually, looked at it, and asked, "Chen Zhou, shall we analyze the data first?"

Chen Zhou thought for a while and nodded: "Let's do the data analysis first, and go back to study the preparation process at night. The two are also related."

Shen Jing looked at Chen Zhou, good guy, you really have energy...

Seemingly knowing what Shen Jing was thinking, Chen Zhou looked at the senior and said with a smile, "It's already started, so there's no need to delay. Now that the experimental data is available, let's grasp it with both hands."

After a pause, Chen Zhou added: "Grasp with both hands, both hands must be hard!"

(End of this chapter)