SEMICONDUCTOR - created from Mind Map

Página 1

STRUKTUR ATOM

intrinsic Semicondutor

Extrinsic Semoconductor

JALUR TENGAAH (ENERGY BAND)

PENGKELASAN BAHAN

Accordiing to Bohr, atoms have a planetary structure that consists of a central nucleus, surrounded by orbiting electrons. Nuclues contains protons and electrons. Also electrons orbit the nucleus.

The orbit paths of the elctrons surrounding te nucleus are called shells.each shell has a defined number of electrons it will hold (2n 2). n=1, 2, 3,...

Bohr's Atomic Theory

The outer shell is called the valence shell and elctrons at this layer are called valence electrons. Maximum number of velence electron is 8. The material is more concuctive if less electron velence orbiting the outer shell.

An intrinsic semiconductor, also called an un doped semiconducor or i-type semiconductor, is a pure semiconductor without any significant dopant species present.

Pure forms of semiconductors

An extrinsic semiconductor is one that has been doped, that is, into which a doping agenthas been introduced, giving it different electrical properties than the intrinsic (pure) semiconductor.

Impurities are added to improve conductivity

Conductor

Semiconductor

Insulator

Occupied by many conduction electrons, causing metal to become good electric conductor.

Enables some electrons with enough energy to jump from the velence band to the conduction band easily.

Temperature low- no free electron in the conduction and band.

Temperature high-electric conductivity high.

Large number of electrons being excited into the conduction band, leaving a large number of holes in the valence band.

Valence band-filled with electrons.

Conduction band-empty.

Band gap-empty.

Electrons are unable to gain enough energy to jump from the valence band to the conduction band.

Conductor

Insulator

Semiconductor

Low resistance which allows electrical current flow.

Charge flows freely.

Copper, silver, gold, aluminium, nicket etc.

High resistance which suppresses electrical current flow.

Almost no charge flows.

Glass, ceramic, plastic, wood etc.

Can allow or suppress electrical current flow.

Conductiviity lies between conductor and insulator.

Carbon, silicon, germanium etc.

Página 2