Hand rubbing nuclear fusion live in the wilderness

Chapter 415 Orbital Hybridization - The Graphene Bandgap Problem

The lithography machine for photo-etched carbon-based chips has been assembled, and the basic materials needed are also available. It is self-evident what to do next.

Most of the audience in the live broadcast room are looking forward to the following things, hoping for the arrival of carbon-based chips.

As for why it is the vast majority and not all, it is naturally because there are bad people among the masses.

In the simulated space, South Korea handles the graphene single crystal wafer material used to manufacture carbon-based chips in a high-standard clean and dust-free chemical laboratory.

Having a graphene single crystal wafer material does not mean that carbon-based chips are guaranteed.

Ultra-high-purity graphene single-crystal wafers are only the most basic materials for manufacturing carbon-based chips. In addition, there are carbon nanotubes and high-purity silicon carbide crystals that need to be attached.

Just like the single crystal silicon of silicon-based chips, graphene single crystal has excellent performance, but because this book is a single crystal grade material, it also needs to be doped with other ionic materials to manufacture corresponding P and N semiconductors.

This step is inevitable whether it is on a silicon-based chip or a carbon-based chip.

Of course, the method of doping graphene single crystal wafers and the doped ion materials are definitely different from single crystal silicon.

Carbon and silicon, both of these two materials belong to the carbon group elements, and both have four electrons in the outermost shell. The two elements have very similar valence shell electron configurations. The difference is that the number of protons in the inner core is different from the number of electrons in the outer shell.

Carbon has 6 protons in its nucleus and silicon has 14 protons in its nucleus.

The number of electrons in carbon is 6, divided into two layers, 2 in the inner layer and 4 in the outer layer.

The number of electrons in silicon is 14, divided into three layers, 2 in the inner layer, 8 in the middle layer, and 4 in the outer layer.

The number of protons and electrons is different, which leads to their different bonding properties, and also leads to their different bonding orbitals, properties and corresponding bond energy levels when facing different materials.

In an easier-to-understand phrase, carbon atoms can form compounds that are more stable than silicon when facing various other atoms.

Covalent bonds are formed between carbon atoms and between carbon atoms and other atoms. The bond energy is large and the compound is relatively stable, so a wide variety of compounds can be formed in nature.

This is why on the earth, the content of silicon in the crust is second only to oxygen and far more than carbon, but the types of compounds of silicon in nature are not as many as those of carbon.

Because silicon compounds are not as stable as carbon.

And this, in fact, can be applied to the manufacture of carbon-based chips,

The theoretical basis of using carbon compounds to manufacture corresponding P and N semiconductors is the 'orbital hybridization theory'.

The problem to be solved is the 'band gap' problem of graphene single crystal material.

The lack of band gap of graphene single crystal materials limits the application of graphene in logic circuits.

It is equivalent to the light at home without a switch, always on.

The "orbital hybrid theory" was proposed in 1931 by American chemist Pauling on the basis of the valence bond theory of atoms, and it belongs to the modern valence bond theory.

However, it enriches and develops the modern valence bond theory in terms of bonding ability and molecular spatial configuration.

The so-called orbital hybridization, in short, means that when forming a molecule, due to the mutual influence of atoms, several different types of atomic orbitals with similar energy are mixed and recombined into a new set of orbitals.

This process of orbital recombination is called hybridization, and the new orbitals formed are called hybrid orbitals.

When molecules are formed through the hybrid orbital theory, there are processes such as excitation, hybridization, and orbital overlap in general materials.

For example, the formation process of the ch4 molecule: an electron in the 2s orbital of the carbon atom absorbs energy and jumps to the 1p empty orbital. This process is called excitation.

但这个时候各个轨道的能量并不完全相同，于是1个2s轨道和3个2p轨道“混合”起来，形成能量相等、成分相同的4个sp3杂化轨道
然后4个sp3杂化轨道上的电子间相互排斥，使四个杂化轨道指向空间距离最远的正四面体的四个顶点，碳原子的4个sp3杂化轨道分别与4个h原子的1s轨道形成4个相同的σ键，从而形成ch4分子。

Since the four ch bonds are identical, the formed ch4 molecule is a regular tetrahedron with a bond angle of 10928'.

The reason for doing this is that the strength of the chemical bond formed by the hybrid orbital is stronger, and the energy of the system is lower, which can further improve the stability of the material.

This method is applied to the graphene single crystal wafer material, which can effectively stabilize the performance of the wafer and make up for the shortcomings of the graphene material.

As we all know, graphene materials have many advantages, such as very hard properties in a very thin case, extremely high toughness, good conductivity and so on.

Therefore, it has many uses and is very extensive.

From optics, electricity, and mechanical properties, to materials science, micro-nano processing, energy, biomedicine, and drug delivery, it has a wide range of applications.

But behind the excellent performance, there are naturally disadvantages.

In addition to being very difficult and expensive to produce graphene on a large scale, graphene is highly reactive with oxygen and heat (commonly).

Because graphene has good thermal conductivity, it is not so stable, although later scientists found a method that can produce a large amount of graphene using CVD.

However, the inability to exist stably in an oxygen environment is a huge disadvantage of graphene, including the graphene single crystal wafer material prepared by Korean won.

If it reacts with oxygen at high temperature, it will lead to the formation of graphene oxide, which will destroy the properties of graphene itself until it loses its electrical conductivity.

This can be said to be a fatal shortcoming for graphene materials.

After all, if graphene is used to make carbon-based chips, it is impossible not to commercialize them.

For commercial applications, you cannot equip every chip with an oxygen-free environment or a vacuum environment.

Not to mention the money and resources that need to be spent, it is not practical at all for chips that are extremely demanding on the environment.

In response to this shortcoming, experts from various countries are looking for ways to make up for it, but so far, there is still no stable and effective way to make up for it.

The orbital hybridization technology can effectively make up for this shortcoming.

Because the electron orbital after hybridization is more concentrated in angular distribution than the original one, so that it overlaps with the atomic orbitals of other atoms to a greater extent, and the covalent bond formed is stronger.

In this way, graphene materials processed by hybrid orbital technology will no longer be afraid of oxygen and high temperature environments.

Of course, hybrid orbital technology is not without its drawbacks.

First of all, after the theory of orbital hybridization was proposed in 1931, this theory and technology have not yet fully matured for nearly 100 years.

Although the current hybrid orbital technology has been applied to various molecular compounds, it has even been written into chemistry textbooks for middle and high schools, and has become molecular chemistry, and even one of the basic subjects of chemistry.

But it is undeniable that, whether it is theory or technology, orbital hybridization theory has not formed its own closed loop so far.

At present, only the valence layer orbital with the closest energy is used in the hybrid orbitals studied in various countries. For example, the C atom in organic matter only uses its 2s and 2p.

However, simply using two or three orbitals does not meet the requirements of orbital hybrid complete bases.

Huaguo is currently the country that has gone the farthest on carbon-based chips, and relevant researchers have not considered using 'hybrid orbital technology' to improve the stability of carbon-based chips.

But it is a pity that this technology is not taken seriously in China or even in the whole world, and there are very few people who are proficient in this area.

Although this technology has given birth to two Nobel Prizes in chemistry, it is still an unpopular specialty.

This may be the two times that the Nobel Prize has been wronged. After all, the majors that have won the Nobel Prize will basically attract the attention and investment of the whole world in the following years.

But the theory of orbital hybridization does not. Before 2010, there were very few schools in the world offering this major.

How little is it?

It is probably that if you have studied this major and then reached the doctoral stage, your supervisor may be a Nobel laureate or a disciple of a Nobel laureate.

Well, probably the scarcity of talent to this extent.

However, with the increase in importance later on, the course of orbital hybridization has become widespread, and even some majors, such as molecular chemistry, have made it a compulsory course in theoretical chemistry.

However, there are still very few people who learn this stuff.

But this can't be blamed on the theory of orbital hybridization, because it is too difficult to learn.

The middle and high school stage is okay, it is really very simple, as long as you have mastered VSEPR, Pauli exclusion principle, Hund's rule, and can write 1s2s2p, three kinds of unit cells are enough.

But at the university level, the difficulty of this thing is like asking a liberal arts student to understand real variable functions + functional analysis + topology + abstract algebra.

Simply hopeless.

It is said that mathematics and physics make people lose their hair and make people Mediterranean, but if you want to learn this stuff, the speed of hair loss will be faster than if you go to Shaolin to become a monk.

In addition, the theory of orbital hybridization is not clear. At present, it is almost only used to describe geometric shapes or environments in academia. It is too difficult to find a job, so few people learn it.

In addition, over-emphasizing the other "importance" of hybridization may cause unnecessary "detours" in the future study of chemistry.

Therefore, even those who study chemistry rarely have a minor in orbital hybridization theory.

Few people learn, and the theory is immature closed loop. This is the first point.

The second point is derived from the first point.

Through orbital hybridization technology, only in the process of forming molecules, the atomic orbitals with similar energy of the central atom can be hybridized, and isolated atoms cannot be hybridized.

This limits the orbital hybridization technology.

It should be known that in various chemical experiments, sometimes the elements that need to be used have great differences in the energy of the central atom.

It can be said that one is in the sky and the other is on the ground.

In this way, the application of orbital hybridization technology is limited.

Despite its drawbacks, the value of orbital hybridization technology is high.

On this point, the South Korean won is more aware than other countries.

Because of the carbon-based chip technology, he studied the theory of orbital hybridization from beginning to end.

Although it was painful during the learning process, after finishing the learning, Han Yuan realized that this technology is not only applied to the preparation of carbon-based chips.

Instead, it has a fairly broad application market in non-theoretical chemistry and polymer chemistry.

Hearing Han Yuan's commentary, the audience in the live broadcast room were dazed and staring.

[Orbital hybrid technology?Orbital hybridization theory?what is this? 】

【Grass!This is what I studied in college, and it lasted four years. I am now a senior, and I still don’t understand this stuff. I have taken the make-up exam twice. 】

[What a coincidence upstairs?I also learned this, commit crimes, save the children. 】

[I am a sophomore in high school, and I am about to participate in the IPHO Chemistry Provincial Competition. I am currently frantically making up this stuff, and my head is already bald. 】

[High school teachers don't talk about this stuff, it's a bit difficult to say, if you say it's organic in college, you must talk about it, and then when you go to college, the teacher asks, you know this, and I won't talk about it if I know.You want to refute, but you have a group of classmates with comprehensive knowledge, and the voice is drowned out, so you jumped, so you were confused, so you laid the foundation for failing the class. 】

[Everyone is talking about this, I want to ask, what is this thing, I'm crying, I haven't studied it in high school or university. 】

[I, who only went to junior high school, looked dumbfounded. 】

[A cricket track hybrid doesn't understand, isn't this live broadcast room per capita a postdoctoral fellow? ——]

[Are you still scolding upstairs? 】

[About hybridization theory, let me say a few points]

[The chemistry teacher of Harbin University of Science and Technology warmly reminds all students, don’t think that it’s okay if you can’t learn hybridization theory in high school, you can’t escape university, and what should come will always come. 】

[Heh, it’s fine if I don’t apply for this stuff in my university. 】

[Stop dreaming upstairs, this thing is compulsory as long as you apply for a major in chemistry, and even majors related to graphene are compulsory. 】

Not to mention ordinary viewers, even the experts who were studying in the live broadcast room and scientific researchers from various countries were a little confused and confused.

They know orbital hybridization technology and theory, but for the theoretical course of orbital hybridization technology, it is only to the extent that they know it.

Just like ordinary people know about Huaguo's "Dongfeng series" missile express, it is limited to this.

Of course, if it happened to be about chemistry, but not an expert in orbital hybridization theory, he would know the explosive power, radius, lethality, and effective strike radius of this 'Dongfeng Express' in more detail.

But how to make a 'Dongfeng Express' is not clear.

Although many universities have opened orbital hybridization theory majors in recent years, and some people have studied this area, the emergence of top talents takes time to accumulate.

And for a major that has just been established, let alone top talents, it is a problem for many people to graduate.

Four years for university, three years for graduate students, three years for some doctors, and four years for others. It takes more than ten years just to study.

As far as Huaguo is concerned, most universities offer this major, basically after 10 years.

Up to now, many students have not yet graduated, so where do the top talents come from.

(End of this chapter)