Volume 1: Student Life Chapter 249: Grasp with both hands, both hands must be strong
Shen Jing turned around and whispered to Dr. Wu.
Chen Zhou shifted his attention to the experimental equipment.
Just now, Dr. Wu's words reminded him.
In diamond doping experiments, carrier concentration affects the Hall mobility.
The Hall mobility directly reflects the degree of boron doping in diamond.
In addition, the boron doping of diamond is achieved by adding a boron source into the reaction chamber for preparing diamond film by MPCVD method .
As for the boron source, boron-containing gases such as B2H6 and B(CH3)3 are generally used.
When the boron doping concentration is high, the prepared diamond doping contains many point defects, line defects and surface defects.
These defects can capture carriers, affect the Hall mobility of diamond materials, and further affect the prepared boron-doped diamond.
"Sure enough, whether it is the preparation of the diamond film itself or the preparation of single crystal diamond under the doping experiment, they are all contradictory experiments..." Chen Zhou thought to himself.
After thinking about it, Chen Zhou said something 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, we can also refer to samples from nature.
However, for n-type doping, we can only continue to explore.
In fact, the n-type doped phosphorus element was explored step by step from nitrogen, sulfur, and lithium.
The covalent bond radius of phosphorus is 1.4 times that of carbon, and its energy level is 0.58 MeV below the bottom of the conduction band.
Because of these properties, phosphorus can form shallow energy levels in diamond films and is therefore an ideal element for achieving n-type doping in 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 ongoing experimental device and said, "It's OK. It's not much different from the previous times."
After a pause, he looked at Chen Zhou and said with a smile: "It depends on the results of your data processing."
Hearing this, Chen Zhou smiled and said, "We'll try our best."
Peng Fei added, "If you need any help, just let me know."
Chen Zhou nodded: "Don't worry, I won't be polite."
After saying that, the two looked at each other and smiled.
Compared with others, Peng Fei, who was arranged to pick them up at the high-speed rail station at the beginning, made Chen Zhou feel much more comfortable.
After thinking for a while, Chen Zhou asked, "What is the current phosphorus doping concentration in diamond?"
Peng Fei did not answer directly, but said: "Because the phosphorus doping concentration directly affects the carrier mobility, when the carrier concentration is low, the ionized impurity scattering has less impact and the mobility is higher."
"In 2012, Dr. P et al. increased the room temperature carrier mobility to 780 cm2/(V·s) by reducing the phosphorus doping concentration in (100) crystal face diamond."
"So, based on their results, we further reduced the phosphorus doping concentration. The phosphorus doping concentrations of these 10 groups of experiments were selected in the range of 4×10^15/cm3 to 2×10^15/cm3."
Chen Zhou nodded. The 10 groups of experiments were used as a control for each other.
Chen Zhou remembered something else and asked, "You will also conduct tomorrow's co-doping experiment, right?"
Peng Fei replied: "That's right. The co-doping experiment is actually n-type doping. However, whether we use the MPCVD method to dope during the growth process or the ion implantation method, it is still difficult to achieve n-type doping of diamond with a single element."
"But by doping diamond with two or more elements, it is much easier to achieve n-type conductivity in diamond."
After a pause, Peng Fei continued: "In single element n-type doping, nitrogen and sulfur are not suitable options. But in co-doping, co-doping of boron and nitrogen, co-doping of boron and sulfur, and co-doping of phosphorus and nitrogen can all achieve the conductivity of diamond."
After listening to Peng Fei's words, Chen Zhou asked, "This topic is mainly about 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 saying that, Peng Fei glanced at Chen Zhou and chuckled, "Why? Are you interested in the properties and applications of diamond semiconductor materials?"
"Somewhat interested." Chen Zhou did not deny it, and instead told Peng Fei about the particle accelerator experimental diode.
After listening to this, Peng Fei looked at Chen Zhou in surprise and said, "I didn't expect you to be involved in such a physics project?"
Chen Zhou replied: "This is the topic of Dean Yang of the School of Physics. I will be responsible for the data processing part."
Although Chen Zhou spoke simply, Peng Fei heard a different meaning.
The research on nuclear physics can be classified as high-energy physics. In China, it is basically a research project of the National Key Laboratory.
Chen Zhou is now involved in such a project, which I have to say is very impressive.
Peng Fei thought for a moment before saying, "If you are interested, you can talk to Dr. Wu about it. After this topic is solved, you can join the next topic. In addition, the 38th Institute of Huake Group is currently conducting research on rare earth magnetic semiconductors, which have a wide range of applications in nuclear physics."
Chen Zhou said softly: "Forget it. I haven't even prepared the academic report I'm going to give in the United States next month."
Peng Fei smiled and said, "Oh, right. I almost forgot that you are a mathematician. Speaking of which, this is an international academic exchange conference. I am so envious..."
Chen Zhou also smiled, and the two stopped talking and focused their attention on the experimental device.
The two sets of experiments took quite a while, and in one morning, only half of the experiments were completed.
Chen Zhou and Shen Jing, who had spent the whole morning in the laboratory, discussed the matter during lunch.
After half a day in the morning, the two of them had fully understood the mechanism of the experiment.
Especially Shen Jing, through communication with Dr. Wu, his understanding of this experiment is no less than that of Chen Zhou.
Of course, only for now.
Whether this guy will forget it in two days, only he himself knows.
In the afternoon, if the two of them stayed in the laboratory for another half day, it would not be of much significance.
Therefore, Chen Zhou and Shen Jing discussed and decided to first ask Dr. Wu for the experimental data and start the specific data analysis work.
What the two did not expect was that after they finished their meal, Peng Fei took them to Dr. Wu's office.
Dr. Wu was working on the computer. When she saw the few people coming in, she said directly, "I guess you are bored staying in the laboratory. I have just sorted out the experimental data. You can do data analysis this afternoon."
"There are also some of my preliminary processing of the data, which you can refer to."
Chen Zhou and Shen Jing looked at each other. Isn't Dr. Wu too knowledgeable?
But then Chen Zhou thought of something and couldn't help muttering in his heart: "Could it be that Dr. Wu processed the data? This is so embarrassing..."
Dr. Wu added: "However, because the topic is confidential, you can only use the computers in the institute to work, and you cannot bring them back to the hotel."
Chen Zhou and Shen Jing nodded at the same time to show that they understood.
After all, it is a project of Huake Group. If it was not confidential, it would make the two of them even more surprised.
A small office with two computers.
It just so happened that Chen Zhou and Shen Jing each had one.
The two of them spent their afternoon here.
Shen Jing turned on the computer and casually clicked on the data. While looking at it, he asked, "Chen Zhou, shall we analyze the data first?"
Chen Zhou thought about it and nodded: "Let's do the data analysis first, and then go back to study the preparation process in the evening. The two are also related."
Shen Jing looked at Chen Zhou. Wow, you really have energy...
As if knowing what Shen Jing was thinking, Chen Zhou looked at the senior and said with a smile, "It has already started, there is no need to delay. Now that we have the experimental data, we can focus on both."
After a pause, Chen Zhou added: "Grasp it with both hands, and both hands must be strong!"
