What are transistors made of?

Electrons: Negatively charged particles.
Holes: Positively charged "absence" of electrons.

Transistors are primarily made from semiconductor materials.

Semiconductor Materials in Transistors

The composition of a transistor largely depends on the type and application, but generally involves semiconductor materials. Here's a breakdown:

Silicon (Si): The most commonly used material due to its abundance, cost-effectiveness, and suitable electrical properties. Most transistors are made from very pure silicon.
Germanium (Ge): Historically important, but less common now due to its sensitivity to temperature. Some transistors are made from germanium.
Other Semiconductors: Certain specialized transistors utilize other semiconductor materials to achieve specific performance characteristics. The reference indicates "certain other semiconductor materials are sometimes used". These may include:
- Gallium Arsenide (GaAs): Used in high-frequency applications.
- Silicon Carbide (SiC): Used in high-power, high-temperature applications.
- Gallium Nitride (GaN): Used in high-power, high-frequency applications.

Transistors control the flow of electrical current. Depending on the type of transistor, the charge carriers can be:

Transistors can be classified based on the type of charge carrier(s) they use:

Field-Effect Transistors (FETs): Utilize only one kind of charge carrier.
Bipolar Junction Transistors (BJTs): Utilize two kinds of charge carriers.

Material	Use	Notes
Silicon (Si)	General-purpose transistors	Most common, readily available, and well-understood.
Germanium (Ge)	Early transistors, specialized apps	Sensitive to temperature changes.
Gallium Arsenide	High-frequency applications	Provides faster switching speeds than silicon in some cases.
Silicon Carbide	High-power, high-temperature	Suitable for extreme conditions.
Gallium Nitride	High-power, high-frequency	Gaining popularity in power electronics and RF applications.