This document discusses semiconductors and provides details about their properties and characteristics. It defines a semiconductor as a material with resistivity between that of a conductor and insulator. Some key points made in the document are:
- Semiconductors have properties like negative temperature coefficient of resistance and their conductivity can change when doped with impurities.
- Common semiconductors include silicon and germanium which form covalent bonds and have small energy gaps between valence and conduction bands.
- Semiconductors can be doped as n-type or p-type to introduce free electrons or holes that serve as majority carriers for current flow. A pn junction is formed when a p-type and n-
This ppt is about semiconductor diodes.You can get every basic information about PN junction diode and its working and some more information about the semiconductors.
This ppt is about semiconductor diodes.You can get every basic information about PN junction diode and its working and some more information about the semiconductors.
Introduction to Semiconductor Devices.
In modern world no other technology permeates every nook and cranny of our existence as does electronics.
Application of electronics are : Televisions, radios, stereo equipment, computers, scanners, electronic control systems (in cars for example) etc.
Introduction
Semiconductor is a solid substance that has conductivity between that of an insulator and that of most metals, either due to the addition of an impurity or because of temperature effects. Devices made of semiconductors, notably silicon, are essential components of most electronic circuits.
Examples: Silicon, Germanium, Carbon
Intrinsic & Extrinsic Semiconductor
Semiconductors are mainly classified into two categories: Intrinsic and Extrinsic. An intrinsic semiconductor material is chemically very pure and possesses poor conductivity. It has equal numbers of negative carriers (electrons) and positive carriers (holes). Where as an extrinsic semiconductor is an improved intrinsic semiconductor with a small amount of impurities added.
The Doping of Semiconductors
The addition of a small percentage of foreign atoms in the regular crystal lattice of silicon or germanium produces dramatic changes in their electrical properties, producing n-type and p-type semiconductors.
Pentavalent impurities
Impurity atoms with 5 valence electrons produce n-type semiconductors by contributing extra electrons.
Trivalent impurities
Impurity atoms with 3 valence electrons produce p-type semiconductors by producing a "hole" or electron deficiency.
N-Type Semiconductor
The addition of pentavalent impurities such as antimony, arsenic or phosphorous contributes free electrons, greatly increasing the conductivity of the intrinsic semiconductor. Phosphorous may be added by diffusion of phosphine gas (PH3).
P-Type Semiconductor
The addition of trivalent impurities such as boron, aluminum or gallium to an intrinsic semiconductor creates deficiencies of valence electrons,called "holes". It is typical to use B2H6 diborane gas to diffuse boron into the silicon material.
Diodes
A device that blocks current in one direction while letting current flow in another direction is called a diode. Diodes can be used in a number of ways. For example, a device that uses batteries often contains a diode that protects the device if you insert the batteries backward. The diode simply blocks any current from leaving the battery if it is reversed -- this protects the sensitive electronics in the device.
This presentation gives a lot of information about
Semiconductor Devices.This is presented by Rajesh Kumar Sangani from Rajiv Gandhi University of Knowledge Technologies,Basar Dist
Adilabad,A.P,India.
This slide give you idea about the atomic structure, classification of solids based on valance electron, free electron, energy band description, why the silicon is used as semiconductor substance compare to germanium, semiconductor and its types.
Introduction to Semiconductor Devices.
In modern world no other technology permeates every nook and cranny of our existence as does electronics.
Application of electronics are : Televisions, radios, stereo equipment, computers, scanners, electronic control systems (in cars for example) etc.
Introduction
Semiconductor is a solid substance that has conductivity between that of an insulator and that of most metals, either due to the addition of an impurity or because of temperature effects. Devices made of semiconductors, notably silicon, are essential components of most electronic circuits.
Examples: Silicon, Germanium, Carbon
Intrinsic & Extrinsic Semiconductor
Semiconductors are mainly classified into two categories: Intrinsic and Extrinsic. An intrinsic semiconductor material is chemically very pure and possesses poor conductivity. It has equal numbers of negative carriers (electrons) and positive carriers (holes). Where as an extrinsic semiconductor is an improved intrinsic semiconductor with a small amount of impurities added.
The Doping of Semiconductors
The addition of a small percentage of foreign atoms in the regular crystal lattice of silicon or germanium produces dramatic changes in their electrical properties, producing n-type and p-type semiconductors.
Pentavalent impurities
Impurity atoms with 5 valence electrons produce n-type semiconductors by contributing extra electrons.
Trivalent impurities
Impurity atoms with 3 valence electrons produce p-type semiconductors by producing a "hole" or electron deficiency.
N-Type Semiconductor
The addition of pentavalent impurities such as antimony, arsenic or phosphorous contributes free electrons, greatly increasing the conductivity of the intrinsic semiconductor. Phosphorous may be added by diffusion of phosphine gas (PH3).
P-Type Semiconductor
The addition of trivalent impurities such as boron, aluminum or gallium to an intrinsic semiconductor creates deficiencies of valence electrons,called "holes". It is typical to use B2H6 diborane gas to diffuse boron into the silicon material.
Diodes
A device that blocks current in one direction while letting current flow in another direction is called a diode. Diodes can be used in a number of ways. For example, a device that uses batteries often contains a diode that protects the device if you insert the batteries backward. The diode simply blocks any current from leaving the battery if it is reversed -- this protects the sensitive electronics in the device.
This presentation gives a lot of information about
Semiconductor Devices.This is presented by Rajesh Kumar Sangani from Rajiv Gandhi University of Knowledge Technologies,Basar Dist
Adilabad,A.P,India.
This slide give you idea about the atomic structure, classification of solids based on valance electron, free electron, energy band description, why the silicon is used as semiconductor substance compare to germanium, semiconductor and its types.
Advancements of Semi conductors and Superconductorsadnanalvi051
explained what are semiconductors and superconductors and their uses. Also nowadays revolutions and advancements in semiconductors as superconductors. After reading these Slides one can easily understand about semiconductors and Superconductors, Nowadays our life is full of semiconductor usage.
Semiconductor.pdf description ki last lin...KALPESH-JNV
Semiconductors (SC) are a class of materials that exhibit intermediate electrical conductivity between conductors (such as metals) & insulators (such as ceramics / plastics). They are used extensively in modern electronics, as the basis for the design & fabrication of transistors, diodes, integrated circuits.
The discovery of the SC properties dates back to the late 19th century, when experiments were carried out on the electrical conductivity of various materials. In 1874, Edwin Hall discovered the phenomenon of Hall effect, which led to the discovery of SC. The Hall effect occurs when a magnetic field is applied perpendicular to the flow of electric current in a conductor, resulting in a voltage difference across the conductor. This effect was found to be more pronounced in certain materials, such as Si & Ge, which led to further investigations into their electrical properties.
SC are characterized by their unique band structure, which determines their electrical conductivity. In an ideal SC crystal, the valence band (the highest occupied energy band) is separated from the conduction band (the lowest unoccupied energy band) by a bandgap. The bandgap is a measure of the energy required to move an electron from the valence band to the conduction band, and determines whether a material is a conductor, an insulator, or a SC.
At absolute zero temperature, all electrons in a SC crystal occupy the valence band, and there are no electrons in the conduction band. However, as the temperature increases, some of the electrons gain enough energy to jump across the bandgap and move to the conduction band, where they are free to move and conduct electricity. This process is called thermal excitation, and it is responsible for the temperature dependence of the electrical conductivity of SC.
SC can be classified into two main types based on their doping properties: intrinsic and extrinsic. Intrinsic SC are pure materials such as Si or Ge, which have no impurities or dopants added to them. Intrinsic SC have a relatively low electrical conductivity at room temperature due to the presence of the bandgap. Extrinsic SC, on the other hand, are doped with impurities to modify their electrical properties.
Doping is the process of intentionally introducing impurities (also called dopants) into a SC crystal to modify its electrical properties. The impurities can either donate or accept electrons, creating excess or deficient electrons, respectively, in the crystal lattice. This alters the band structure and conductivity of the SC, making it more useful for electronic applications.
Extrinsic SC can be further classified into two types: n-type and p-type. N-type SC are doped with impurities that have excess electrons (such as phosphorus)
Jane se phele niche vali video dekh lo (VERY IMP)
https://www.youtube.com/watch?v=V5qMCRAZTN8
The following presentation is a part of the level 4 module -- Electrical and Electronic Principles. This resources is a part of the 2009/2010 Engineering (foundation degree, BEng and HN) courses from University of Wales Newport (course codes H101, H691, H620, HH37 and 001H). This resource is a part of the core modules for the full time 1st year undergraduate programme.
The BEng & Foundation Degrees and HNC/D in Engineering are designed to meet the needs of employers by placing the emphasis on the theoretical, practical and vocational aspects of engineering within the workplace and beyond. Engineering is becoming more high profile, and therefore more in demand as a skill set, in today’s high-tech world. This course has been designed to provide you with knowledge, skills and practical experience encountered in everyday engineering environments.
Event Management System Vb Net Project Report.pdfKamal Acharya
In present era, the scopes of information technology growing with a very fast .We do not see any are untouched from this industry. The scope of information technology has become wider includes: Business and industry. Household Business, Communication, Education, Entertainment, Science, Medicine, Engineering, Distance Learning, Weather Forecasting. Carrier Searching and so on.
My project named “Event Management System” is software that store and maintained all events coordinated in college. It also helpful to print related reports. My project will help to record the events coordinated by faculties with their Name, Event subject, date & details in an efficient & effective ways.
In my system we have to make a system by which a user can record all events coordinated by a particular faculty. In our proposed system some more featured are added which differs it from the existing system such as security.
TECHNICAL TRAINING MANUAL GENERAL FAMILIARIZATION COURSEDuvanRamosGarzon1
AIRCRAFT GENERAL
The Single Aisle is the most advanced family aircraft in service today, with fly-by-wire flight controls.
The A318, A319, A320 and A321 are twin-engine subsonic medium range aircraft.
The family offers a choice of engines
Explore the innovative world of trenchless pipe repair with our comprehensive guide, "The Benefits and Techniques of Trenchless Pipe Repair." This document delves into the modern methods of repairing underground pipes without the need for extensive excavation, highlighting the numerous advantages and the latest techniques used in the industry.
Learn about the cost savings, reduced environmental impact, and minimal disruption associated with trenchless technology. Discover detailed explanations of popular techniques such as pipe bursting, cured-in-place pipe (CIPP) lining, and directional drilling. Understand how these methods can be applied to various types of infrastructure, from residential plumbing to large-scale municipal systems.
Ideal for homeowners, contractors, engineers, and anyone interested in modern plumbing solutions, this guide provides valuable insights into why trenchless pipe repair is becoming the preferred choice for pipe rehabilitation. Stay informed about the latest advancements and best practices in the field.
Water scarcity is the lack of fresh water resources to meet the standard water demand. There are two type of water scarcity. One is physical. The other is economic water scarcity.
Sachpazis:Terzaghi Bearing Capacity Estimation in simple terms with Calculati...Dr.Costas Sachpazis
Terzaghi's soil bearing capacity theory, developed by Karl Terzaghi, is a fundamental principle in geotechnical engineering used to determine the bearing capacity of shallow foundations. This theory provides a method to calculate the ultimate bearing capacity of soil, which is the maximum load per unit area that the soil can support without undergoing shear failure. The Calculation HTML Code included.
CFD Simulation of By-pass Flow in a HRSG module by R&R Consult.pptxR&R Consult
CFD analysis is incredibly effective at solving mysteries and improving the performance of complex systems!
Here's a great example: At a large natural gas-fired power plant, where they use waste heat to generate steam and energy, they were puzzled that their boiler wasn't producing as much steam as expected.
R&R and Tetra Engineering Group Inc. were asked to solve the issue with reduced steam production.
An inspection had shown that a significant amount of hot flue gas was bypassing the boiler tubes, where the heat was supposed to be transferred.
R&R Consult conducted a CFD analysis, which revealed that 6.3% of the flue gas was bypassing the boiler tubes without transferring heat. The analysis also showed that the flue gas was instead being directed along the sides of the boiler and between the modules that were supposed to capture the heat. This was the cause of the reduced performance.
Based on our results, Tetra Engineering installed covering plates to reduce the bypass flow. This improved the boiler's performance and increased electricity production.
It is always satisfying when we can help solve complex challenges like this. Do your systems also need a check-up or optimization? Give us a call!
Work done in cooperation with James Malloy and David Moelling from Tetra Engineering.
More examples of our work https://www.r-r-consult.dk/en/cases-en/
Industrial Training at Shahjalal Fertilizer Company Limited (SFCL)MdTanvirMahtab2
This presentation is about the working procedure of Shahjalal Fertilizer Company Limited (SFCL). A Govt. owned Company of Bangladesh Chemical Industries Corporation under Ministry of Industries.
Final project report on grocery store management system..pdfKamal Acharya
In today’s fast-changing business environment, it’s extremely important to be able to respond to client needs in the most effective and timely manner. If your customers wish to see your business online and have instant access to your products or services.
Online Grocery Store is an e-commerce website, which retails various grocery products. This project allows viewing various products available enables registered users to purchase desired products instantly using Paytm, UPI payment processor (Instant Pay) and also can place order by using Cash on Delivery (Pay Later) option. This project provides an easy access to Administrators and Managers to view orders placed using Pay Later and Instant Pay options.
In order to develop an e-commerce website, a number of Technologies must be studied and understood. These include multi-tiered architecture, server and client-side scripting techniques, implementation technologies, programming language (such as PHP, HTML, CSS, JavaScript) and MySQL relational databases. This is a project with the objective to develop a basic website where a consumer is provided with a shopping cart website and also to know about the technologies used to develop such a website.
This document will discuss each of the underlying technologies to create and implement an e- commerce website.
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Maintaining high-quality standards in the production of TMT bars is crucial for ensuring structural integrity in construction. Addressing common defects through careful monitoring, standardized processes, and advanced technology can significantly improve the quality of TMT bars. Continuous training and adherence to quality control measures will also play a pivotal role in minimizing these defects.
2. Group Member
Name ID
Md. Nasir Uddin Mahamud 152-15-6226
Md. Touhidur Rahman 152-15-6232
Md. Mithu Mia 152-15-6243
Md. Atiqul Islam 152-15-6244
3. Semiconductor
A semiconductor is a substance which has
resistivity (10−4 to 0.5 Ωm) in between
conductors and insulators e.g. germanium,
silicon, selenium, carbon etc.
4. Sl. No. Substance Nature Resistivity
1
2
3
Copper
Germanium
Glass
good conductor
semiconductor
insulator
1.7 × 10−8 Ω m
0.6 Ω m
9 × 1011 Ω m
Resistance material
5. Properties of Semiconductors :
There are three properties of semiconductors.
(i) The resistivity of a semiconductor is less than
an insulator but more than a conductor.
(ii) Semiconductors have negative temperature
co-efficient of resistance .
(iii) When a suitable metallic impurity is added to
a semiconductor, its current conducting properties
change appreciably.
6. Bonds in Semiconductors
The electrons surrounding each atom in a semiconductor are part of a
covalent bond.
A covalent bond consists of two atoms "sharing" a single electron.
Each atom forms 4 covalent bonds with the 4 surrounding atoms.
Therefore, between each atom and its 4 surrounding atoms, 8 electrons are being
shared.
7. Commonly Used Semiconductors
The two most frequently used materials are germanium (Ge) and silicon(si)
Germanium.
The atomic number of germanium is 32.
Therefore, it has 32 protons and 32 electrons.
four electrons in the outer or valence orbit
to shared 8 electrons Germanium to Germanium it make
semiconductor
8. (ii) Silicon
The atomic number of germanium is 14.
Therefore, it has 14 protons and 14 electrons.
four electrons in the outer or valence orbit
to shared 8 electrons Silicon to Silicon it make semiconductor
9. Energy Band Description of Semiconductors
For silicon:
we see that forbiden energy gap is very small valence band to conduction
band.
Being 1.1eV for silicon .
So small energy is needed by their valence electrons to cross over to the
conduction band.
even at room temperature,some of the valence electrons may acquire
sufficient energy to enter into the conduction band thus become free
electrons.
10. For germanium:
we see that forbiden energy gap is very small valence band to
conduction band.
Being 0.7eV for germanium .
So small energy is needed by their valence electrons to cross
over to the conduction band.
even at room temperature, some of the valence electrons may
acquire sufficient energy to enter into the conduction band thus
become free electrons.
11. Summary:
we know that free electron means electricity.
so we said that, energy band help us to
understanding the current flow through a
semiconductor.
12. Effect of temperature on semiconductor
This is a very important point to keep in mind,
namely
(i) At absolute zero temperature
(ii) Above absolute zero temperature
13. At absolute zero temperature:
All the electrons are tightly held by the semiconductor.
The co-valent bonds are very strong.
There is a large energy gap between valence band and
conduction band.
So no valence electron can reach the conduction band become
free electron.
The semiconductor behaves a perfect insulator.
14. Above absolute zero temperature
Some of the co-valent bonds in the semiconductor break due to the thermal energy
supplied.
The breaking the bonds electrons become free.
When temperature is raised.
Valence electrons acquire sufficient energy to enter into the conduction band.
Become free electrons.
it may be noted that each time a valence electrons enters into the conduction band.
'Hole' is created in valence band.
so we said that above absolute zero temperature, the current flow through a
semiconductor.
16. (i) n-type semiconductor
When a small amount of pentavalent impurity is added to a pure
semiconductor it is known as n-type semiconductor.
We use pentavalent impurity like arsenic
Arsenic has five valence electrons
When a small amount of arsenic is added to germanium crystal, some number
of free electrons become available in the crystal.
Though each arsenic atom provides one free electron
That means small amount of arsenic impurity provides enough atoms to
supply millions of free electrons.
17. n-type conductivity
The current conduction in an n-type semiconductor by free
electrons
the free electrons in the crystal will be directed towards
the positive terminal
As the current flow through the crystal is by free electrons
which are carriers of negative charge, therefore, this type
of conductivity is called negative or n-type conductivity
18. p-type Semiconductor :
When a small amount of trivalent impurity is added to a pure
semiconductor, it is called p-type
We use trivalent impurity like gallium
gallium has three valence electrons
When a small amount of gallium is added to germanium crystal, there
exists a large number of holes in the crystal.
This missing electron is called a hole. Therefore, for each gallium atom
added, one hole is created. A small amount of gallium provides millions of
holes.
19. p-type conductivity
The current conduction in p-type semiconductor is predominantly
As the holes are positively charged, there- fore, they are directed
towards the negative terminal, constituting what is known as hole
current.
20. Majority and Minority Carriers:
In case of n-type:
N-type
I. N-type material has a large number of free electrons.
II. The free electrons in this case are considered majority carriers since the
majority portion of current in n-type material is by the flow of free electrons
and the holes are the minority carriers
21. In case of p-type:
I. P-type material has a large number of holes.
II. In a p-type material, holes outnumber the free electrons. Therefore,
holes are the majority carriers and free electrons are the minority
carriers.
22. pn Junction:
When a p-type semiconductor is suitably joined to n-type semiconductor, the
contact surface is called pn junction.
Formation of pn junction:
1. One common method of making pn junction is called
alloying. In this method, a small block of indium (trivalent
impurity) is placed on an n type germanium slab as shown in
Fig. (i). The system is then heated to temperature of about
500ºC.
23. 2. The indium and some of the germanium melt to form a small
puddle of molten germanium-indium mixture as shown in Fig.
(ii).
3. The temperature is then lowered and puddle begins to
solidify. Under proper conditions, the atoms of indium impurity
will be suitably adjusted in the germanium slab to form a single
crystal. The addition of indium overcomes the excess of
electrons in the n-type germanium to such an extent that it
creates a p-type region.
24. 4. As the process goes on, the remaining molten mixture
becomes increasingly rich in indium. When all germanium has
been redeposited, the remaining material appears as indium
button which is frozen on to the outer surface of the crystallized
portion as shown in Fig. (iii). This button serves as a suitable
base for soldering on leads.