Electronics and Semiconductor Materials: An Introduction to Diodes and Their Applications, High school final essays of Physics

Download Electronics and Semiconductor Materials: An Introduction to Diodes and Their Applications and more High school final essays Physics in PDF only on Docsity! Chapter 1 _ Diodes and Applications - eae a ie) s Aen “i & F a 2° ack ea J _— 7 i. r _ 2 ® Lecturer: Dr. Tran Vu Hoang Outline HCMUTE > Tuning-in Activities UD What is Electronics? HCMUTE L The branch of science and technology UL Deal with the motion of electrons in various systems or devices UI Include active electrical components: diodes, transistors, rectifiers ... Battery EE J G&G) HCMUTE What is a Circuit? LI Closed system consists of various components (Electronic) linked to each other to make a circuit functional L) Very small in size L) Have plenty of circuits present in chips Semiconductor Electronic Electronic devices devices circuits and system Electronic Devices HCMUTE 201094 1 antes 7 anes EE J G&G) HCMUTE Electronic vs Electrical Engineering Electronic LJ Semiconductor (usually silicon) LI low intensity currents LJ conduction is finely controlled LI small scale electronic systems: computers, integrated circuit Electrical L) Conductor (Metals and alloys) UL powerful currents LJ conduction is not as finely controlled LJ large scale electrical systems: power transmission, motor control ... Outline HCMUTE > Ideal Diode = S | v Ideal Diode HCMUTE LI the simplest of semiconductor devices but plays a very vital role LI have characteristics that closely match those of a simple switch that can conduct current in only one direction. + - «= + i Anode Cathode Anode Cathode —Reverse bias—p> Forward bias— —-o— —o o- Closed circuit Open circuit Forward biased Reverse biased a S | 1 Semiconductor Materials HCMUTE L) Conductor LI) have very low values of resistivity U) plenty of free electrons floating about within conduction band SG SS OOO WL Conductor their basic atom structure LJ easily pass an electrical current valance band a S | 1 Semiconductor Materials HCMUTE LJ Insulator E LJ have very high resistances LJ have very few or no “free electrons” floating about within their basic atom structure electron L) the electrons are stuck to the parent distribution WG atom and can not move around freely Wy Vt Insulator conduction band forbidden band Cc valance band ee WY 1 Semiconductor Materials HCMUTE L) Semiconductor LI) have electrical properties somewhere in the . on middle, between those of a “conductor” and an “insulator” LI) have very few “free electrons” conduction band Q electrons are still able to flow under special conditions valance band UI it is possible to control its conductivity by controlling the amount of impurities added to the intrinsic Semiconductor semiconductor material Semiconductor Materials L)Ge and Si have received the broadest range of interest in the development of semiconductor devices Valence electron Four valence electrons in the outer (valence) shell Core (+1) / Valence electrons Core (+4) Silicon atom Germanium atom _ * (a) Silicon atom (b) Copper atom Qy Semiconductor Materials HCMUTE Energy Energy Energy a a 4 Band gap | Band gap w—EC = ie 0 0 0 (a) Insulator (b) Semiconductor (c) Conductor 5,6,7,8 4 1, 2,3 valence electrons valence electrons valence electrons LE A Gy) HCMUTE Semiconductor Materials LI The outermost shell of atom is capable to hold up to eight electrons (most stable) LJ Silicon atom forms four covalent bonds with the four neighboring atoms U covalent bonding: each valence electron is shared by two atoms Ly N-type Semiconductor HCMUTE LJ Conduction band electrons > Valence band holes L Electrons = majority carriers Donor ions _ . . . DZ S I Mai ity L) Holes = minority carriers a- _ AY - Oar. suenty Q) Electrically neutral e~ © - © & + + _@® Bp — Minority — & _ — 6 carrier P-type Semiconductor HCMUT * Boron (B) ° Trivalent impurity atom ¢ Acceptor atom Forming covalent bonds with four adjacent silicon atoms = S | v HCMUTE P-type Semiconductor LJ Conduction band electrons < Valence band holes L) Electrons = minority carriers WL Holes = majority carriers U) Electrically neutral Acceptor ions OF O+ : + © 44 Ss OS r Py © ee + 2+" Minority