Semiconductor Electronics Materials Devices And Simple Circuits

Definition of Capacitance:

Capacitance ( ) is the ability of a capacitor to store electric charge. It is defined as the ratio of the charge ( ) stored on each plate to the potential difference ( ) between the plates:

$ \varepsilon_0 8.85 \times 10^{-12} \, F/m A d \kappa \kappa > 1 E_{\text{induced}} E_0 Q V C V Q Q = \text{constant} V = \frac{V_0}{\kappa} C = \kappa C_0 V = \text{constant} Q = \kappa Q_0 C = \kappa C_0 \kappa $

Semiconductors:
Semiconductors are materials with electrical conductivity between that of conductors and insulators. Their conductivity can be modified by adding impurities (doping) to create two types: P-type and N-type semiconductors.
Majority Charge Carriers:

N-type Semiconductor:

Formed by doping a pure semiconductor (like Silicon or Germanium) with Pentavalent impurities (atoms with 5 valence electrons), such as Phosphorus (P), Arsenic (As), or Antimony (Sb).
Pentavalent impurities are called Donor impurities because they donate extra electrons.
Four of the five valence electrons form covalent bonds with neighboring silicon atoms, while the fifth electron becomes a free electron that can move freely.
Since electrons are negatively charged and are the majority carriers, this type is called N-type (Negative-type).
Majority carriers: Electrons
Minority carriers: Holes

P-type Semiconductor:

Formed by doping a pure semiconductor with Trivalent impurities (atoms with 3 valence electrons), such as Boron (B), Aluminum (Al), or Gallium (Ga).
Trivalent impurities are called Acceptor impurities because they create "holes" that can accept electrons.
With only three valence electrons, they cannot complete all four covalent bonds with neighboring silicon atoms, creating a hole (absence of electron) in the crystal structure.
These holes act as positive charge carriers and can move through the crystal when electrons jump into them.
Since holes are positively charged and are the majority carriers, this type is called P-type (Positive-type).
Majority carriers: Holes
Minority carriers: Electrons

Visual Representation:
N-type Semiconductor:

Applications:

Both N-type and P-type semiconductors are used together to form PN junction diodes, transistors, solar cells, LEDs, and various other electronic components.
The junction between P-type and N-type materials creates a depletion region that is fundamental to modern electronics.
Final Answer: