What are P-type & N-type Silicon Semiconductors? | Stanford Advanced Materials (2024)

Semiconductors are critically important in our world. The most significant application is in computerized or radio waves-powered electrical devices. These semiconductors are made of the widely abundant element, silicon. In fact, silicon is at the core of almost all kinds of electronic devices.

One of the reasons why they are widely used in semiconductors is because they are abundant in nature. For example, silicon occurs naturally in sand and quartz, which has a perfect electronic structure. The use of silicon in semiconductors explains why Silicon Valley is the home of many tech companies.

Another very important thing to note about silicon is the impact of doping, a process in which impurities are introduced to enhance the value of an intrinsic semiconductor. Read on to learn more details about doping in silicon semiconductors.

What are P-type & N-type Silicon Semiconductors? | Stanford Advanced Materials (1)

Structure of Silicon

Just like carbon, silicon has 4 electrons in its outer orbital, which contributes to its crystalline structure. Silicon has the appearance of a silvery, metallic substance. However, silicon is not a metal, even though its crystal assumes a metallic structure. In fact, silicon acts as an insulator, allowing only a small amount of electricity to pass through it.

What are P-type & N-type Silicon Semiconductors? | Stanford Advanced Materials (2)

It is neither a good insulator nor a good conductor, hence the name semiconductor. When other elements like phosphorus or boron are introduced into the crystalline structure of silicon, then we have either an n-type or p-type semiconductor.

Types of Semiconductors

Semiconductors are generally materials or elements that behave like normal conductors and also act like typical insulators. However, they cannot be said to be strong conductors or insulators. In practical applications, semiconductors fall into two types of categories, as discussed below.

Intrinsic Semiconductors

Intrinsic semiconductors are made up of only one kind of material, examples of which can either be silicon or germanium. Another name for this type of semiconductor is undoped semiconductors or i-type semiconductors. These are chemically pure semiconductors. In these semiconductors, electrons have energies in only certain bands. The energy bands correspond to a large number of discrete quantum states of electrons. Also, note that the distribution and population of bands in semiconductors is another factor that distinguishes them from metals.

For clarity, the valence band of electrons in metals is typically almost filled under normal conditions, but in semiconductors, only a few electrons exist in the conduction band, just above the valence band. Insulators, on the other hand, have nearly no free electrons, which is why they can’t conduct electricity. Also, in intrinsic semiconductors, the number of holes is equal to the number of excited electrons.

Extrinsic Semiconductors

Extrinsic Semiconductors, on the other hand, are intrinsic semiconductors combined with other materials, such as boron or arsenic. This alters the natural behaviors or characteristics of the intrinsic semiconductors. In other words, when intrinsic semiconductors are doped, what you get are extrinsic semiconductors.

There are two types of extrinsic semiconductors, depending on the type of material that is added. The first type is the n-type semiconductors, which result from the addition of atoms that ve an extra electron. N-type means negative because of the extra electrons, which are typically from group V elements like phosphorus and arsenic. The other is the p-type semiconductors.

They are doped with elements like boron and gallium, which have only three electrons in the outer shell. This means that they are one electron short, unlike the n-type semiconductors. The resulting positive charge earned them the name p-type semiconductors.

Doping in Semiconductor Production

Doping is commonly used in semiconductor production to introduce impurities into an intrinsic semiconductor so as to modulate its electrical, optical, and structural properties. As explained above, doping silicon semiconductors produce the P-type and N-type silicon semiconductors. Generally, doped or extrinsic semiconductors may exhibit better electric conductivities than intrinsic semiconductors, in which case, they are called degenerate. Let’s dive deeper into the differences between the two.

P-Type Semiconductor

Instead of increasing the negative charge in the crystal lattice, the dopant, in this case increases the positive charge. Group III elements like boron or gallium serve as the dopant here. These elements have only 3 electrons in their outer shell, and when it mixes with the silicon crystal lattice, they form holes in the valence band of silicon atoms. Hence, the electrons in the valence band can roam freely, such that the hole moves in the opposite direction to the movement of the electrons.

What are P-type & N-type Silicon Semiconductors? | Stanford Advanced Materials (3)

Since the electrons of the dopant atom are fixed in the lattice, only the positive charges can move around, giving rise to a net positive charge within the silicon-boron lattice. The positive holes earned these semiconductors their name, P-type semiconductors.

N-Type Semiconductors

N-type semiconductors contain dopants that have extra conduction electrons to the host material. A good example is doping silicon with phosphorus. Here, there’s an excess of electron charge carriers. This is because the doping phosphorus atom has one more valence electron than the host silicon atoms.

What are P-type & N-type Silicon Semiconductors? | Stanford Advanced Materials (4)

A silicon atom has 4 electrons bound tightly to its outer orbit. Phosphorus has 5 electrons instead. When combined, there’s a free electron from phosphorus. Since the electron carries a negative charge, this semiconductor is categorized as n-type.


The two types of silicon semiconductors are P-type and N-type semiconductors. These extrinsic semiconductors possess enhanced properties, which make them very useful in the electronic manufacturing industry.

Thank you for reading our article and we hope that it can help you better understand silicon semiconductors. If you want to know more about semiconductor materials, we would like to advise you to visitStanford Advanced Materials(SAM) for more information.

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What are P-type & N-type Silicon Semiconductors? | Stanford Advanced Materials (2024)


What are P-type & N-type Silicon Semiconductors? | Stanford Advanced Materials? ›

N-type semiconductors have an excess of electrons, while p-type semiconductors have an excess of "holes" where an electron could exist. When n-type and p-type semiconductors meet in a PN junction

PN junction
A p–n junction is a combination of two types of semiconductor materials, p-type and n-type, in a single crystal. The "n" (negative) side contains freely-moving electrons, while the "p" (positive) side contains freely-moving electron holes.
https://en.wikipedia.org › wiki
, they form a boundary where electrons from the n-type region fill the holes in the p-type region, creating a depletion zone.

What are p-type and n-type silicon? ›

So, what's the difference? In n-type silicon, the electrons have a negative charge, hence the name n-type. In p-type silicon, the effect of a positive charge is created in the absence of an electron, hence the name p-type.

What is P and n-type In silicon wafer? ›

P-type silicon wafers have been heavily doped with boron, whereas n-type wafers are hardly doped at all. A typical p-type silicon wafer has a resistance of 112, indicating that it is heavily doped. The n-type version is the cheapest and is used in consumer electronics and computers.

What is the difference n-type semiconductor and p-type semiconductor? ›

In a P-type semiconductor, the majority charge carriers are holes (which are positive), thus moves from higher potential to lower potential. The majority charge carries in an N-type semiconductor are electrons (which are negative), thus moves from lower potential to higher potential.

What are p-type semiconductor materials? ›

What is a p-type Semiconductor? A p-type semiconductor is an intrinsic semiconductor doped with boron (B) or indium (In). Silicon of Group IV has four valence electrons and boron of Group III has three valence electrons.

What is n-type silicon used for? ›

N-type silicon is used in a variety of applications, including: Semiconductor devices: N-type silicon is often used in the production of semiconductor devices such as microchips and transistors.

How can you identify materials as P and n-type semiconductor? ›

If Hall coefficient is positive, it is p-type semiconductor. If Hall coefficient is negative, it is n-type semiconductor.

Which is better, N-type or P-type? ›

What is the primary difference between N-Type and P-Type solar panels? The main difference lies in the material used for doping and the resulting efficiency. N-Type panels are typically more efficient due to less light-induced degradation but tend to be more expensive than P-Type panels.

What are P-type and N-type semiconductors used for? ›

N-type semiconductors excel in applications requiring efficient electron flow, like transistors and diodes. They're also key in photovoltaic cells, converting light energy into electricity effectively. P-type semiconductors are crucial for devices like solar cells, where hole movement generates current.

What is an example of an n-type semiconductor? ›

N-type semiconductor examples are silicon doped with arsenic, silicon doped with phosphorus, arsenic doped with Germanium, Germanium doped with phosphorus, and so on are n-type semiconductor examples.

What is n-type material? ›

What is an n-type Semiconductor? An n-type semiconductor is an intrinsic semiconductor doped with phosphorus (P), arsenic (As), or antimony (Sb) as an impurity. Silicon of Group IV has four valence electrons and phosphorus of Group V has five valence electrons.

Is germanium n-type or p type? ›

Germanium is simply an element of the periodic table and not a p-type or n-type semiconductor in itself. To make it p type, trivalent impurities (like Gallium, Indium, Thallium etc) are added, whereas to make in n type, pentavalent impurities (Phosphorus, Arsenic, Antimony, Bismuth etc.)

How are p and N-type semiconductors formed? ›

p-type : When pure/intrinsic semiconductor (germanium/sillicon) is doped with trivalent impurity (indium, gallium, aluminum, boron). n-type : When pure/intrinsic semiconductor (germanium/sillicon) is doped with pentavalent impurity (phosphorous, arsenic, antimony,bismuth).

What is P type silicon layer? ›

A P-type cell has a silicone base with boron atoms infused to create an overall positive charge (hence 'P' type). The top silicone layer of the wafer is infused with phosphorus (N-type) to create a p-n junction for electricity flow. P-type cells are the most common type used in solar panel production.

Are both P type and n-type silicon electrically neutral? ›

The p-type and n-type semi conductors are formed when the impurity atoms, which themselves are electrically neutral, are added to pure semiconductor which is also electrically neutral. Hence the p or n-type semiconductor formed is electrically neutral.

What is P type silicon substrate? ›

The term p-type refers to the positive charge of the hole. In p-type semiconductors, holes are the majority carriers and electrons are the minority carriers. P-type semiconductors are created by doping an intrinsic semiconductor with acceptor impurities (or doping an n-type semiconductor).

Is P type silicon positive or negative? ›

Because an acceptor donates excess holes, which are considered to be positively charged, a semiconductor that has been doped with an acceptor is called a p-type semiconductor; "p" stands for positive.


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