Lecture #6
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Dioda Semikonduktor (Semiconductor Diode)
Basic electronic / Yohandri
Contents : Semiconductor Theory P-N Junction Diode Diode Characteristic
Kompetensi Menjelaskan tentang semikonduktor, dioda persambungan p-n, dan karakteristik dioda
Background The electronics industry today is based on semiconductors, due to our well-developed ability to affect the electronic properties of the solid. Understanding semiconductors allows us to understand the functioning of circuit elements, as well as grasp future possibilities and limitations.
Conductors, Insulators and Semiconductors Conductor is Solids with “free electrons” that is electrons not directly involved in the inter-atomic bonding- are the familiar metals (Cu, Al, Fe, Au, etc). Solids with no free electrons are the familiar insulators (glass, quartz crystals, ceramics, etc.) Silicon is an insulator, but at higher temperatures some of the bonding electrons can get free and make it a little conducting – hence the term “semiconductor” Pure silicon is a poor conductor (and a poor insulator). It has 4 valence electrons, all of which are needed to bond with nearest neighbors. No free electrons.
1. Teori Semikonduktor (Semiconductor Theory) Semiconductor material are in between conductors (like metals) and insulators (like glass)
In pure form, it is non-conducting E.g. silicon crystal - has 4 electrons in its outer orbital, which form perfect covalent bonds with four neighboring atoms, leaving no electrons to conduct electric current The behavior of silicon can be change and turn it into a conductor by doping it. In doping, you mix a small amount of an impurity into the silicon crystal Generally there are two types of semiconductor : Intrinsic Extrinsic
a. Intrinsic semiconductor Intrinsic semiconductor made form pure semiconductor like silicon or germanium.
In low temperature 0 K all of valence electrons are bounded. No free electron
T=0K
Pada temperatur kamar banyak elektron valensi yang terlepas dari ikatan kovalen (free electron) karena tereksitasi termal. Bila diberi medan listrik maka elektron akan bergerak menjadi aliran atau arus listrik Saat atom terionkan maka pada atom akan timbul lubang (hole), elektron yang bebas dari ikatan kovalen disebut Elektron intrinsik. Sedangkan lubang yany terjadi oleh terbebasnya elektron intrinsik disebut lubang intrinsik
b. Extrinsic semiconductor Semikonduktor ekstrinsik dibuat dari campuran bahan semikonduktor intrinsik dengan atom unsur dari kelompok III atau V dalam susunan berkala.
Intrinsik + Kelompok V
Elektron > hole Pembawa muatan negatif Semikonduktor jenis n
Intrinsik + Kelompok III
Hole > elektron Pembawa muatan positif Semikonduktor jenis p
Semiconductor Doping N-type In N-type doping, phosphorus or arsenic is added to the silicon in small quantities Phosphorus and arsenic each have 5 outer electrons The 5th electron has nothing to bond to, so it's free to move around The created free electrons allow an electric current to flow through the silicon Electrons have a negative charge, hence the name Ntype
P-type
I n P-type doping, boron or gallium is the dopant
Boron and gallium each have only three outer electrons When mixed with silicon, they form "holes" in the where a silicon electron has nothing to bond to The absence of an electron creates the effect of a positive charge, hence the name P-type Holes can conduct current. A hole happily accepts an electron from a neighbor, moving the hole over a space
2. Dioda Persambungan P-N (P-N Junction Diode)
Dioda merupakan suatu komponen elektronik yang dapat melewatkan arus pada satu arah saja.
The structure and the circuit symbol are shown below:
p n
pn Junction: open circuit
3. Karakteristik Dioda ( Diode Characteristic)
