Basic electronic components A review Made by Yulia I. Isakova As a template for students’ presentations Good afternoon ladies and gentlemen! My name is Yulia Isakova I am student of TPU. Today I would like to talk with you about basic electronic components. Tomsk 2015

Aim of presentation The aim for today’s presentation is to review basic electronic components which are used to build semiconductor devices. My aim for today’s presentation is to give you information about electronic components which are used to build semiconductor devices.

Outline Different types of materials Conductors Insulators Semiconductors Silicon as the most common material for semiconductors Basic electronic component: Diode Transistor Optoelectronics Examples of application Conclusion This slide shows the content of my presentation. My talk will be in three parts . In the first part I will tell you about different types of materials from the point of their electrical conductivity. Secondly, I’ll explain something about silicon materials. Then we will talk about the most basic electronic components. And finally I will show some examples of their application.

Terminology To permit To contain To join together biased Conductivity Conductors Insulators Semiconductors flow of electrons pure silicon wafer crystalline lattice Device Diodes P-n junction Silicon Transistor Lead Optoelectronics Liggh emmiting diode (LED) Infrared detector To permit To contain To join together biased Firstly, we must become familiar with the terminology, which will be used in my talk today. Here you can see some of the words and their definition.

Electrical conductivity of materials • Materials that permit flow of electrons are called conductors (e.g., gold, silver, copper, etc.). • Materials that block flow of electrons are called insulators (e.g., rubber, glass, Teflon, mica, etc.). • Materials whose conductivity falls between those of conductors and insulators are called semiconductors. • Semiconductors are “part-time” conductors whose conductivity can be controlled. Let us start by mentioning a few facts about electrical conductivity of materials. In fig.1 you can see a range of electrical conductivity for different materials. According to this figure we can divide all materials into three groups: Materials that permit flow of electrons are called conductors (e.g., gold, silver, copper, etc.). Materials that block flow of electrons are called insulators (e.g., rubber, glass, Teflon, mica, etc.). Materials whose conductivity falls between those of conductors and insulators are called semiconductors. Fig. 1 - Electrical conductivity

Silicon Atoms in a pure silicon wafer contains four electrons in outer orbit (called valence electrons). In the crystalline lattice structure of Si, the valence electrons of every Si atom are locked up in covalent bonds with the valence electrons of four neighboring Si atoms. In pure form, Si wafer does not contain any free charge carriers. An applied voltage across pure Si wafer does not yield electron flow through the wafer. – A pure Si wafer is said to act as an insulator. In order to make useful semiconductor devices, materials such as phosphorus (P) and boron (B) are added to Si to change Si’s conductivity. Let’s now talk about silicon. As you can see from Fig 2, atoms in a pure silicon wafer contains four electrons in outer orbit. These electrons are called valence electrons. It can been seen from this figure (Fig. 2c) that In pure form, Si wafer does not contain any free charge carriers. Thus, in order to make useful semiconductor devices we need to add materials such as phosphorus (P) and boron (B) to Si to change its conductivity. Fig. 2 – Atomic configuration and structure of Si

Basic electronic components 1. Diodes A diode is a 2 lead semiconductor that acts as a one way gate to electron flow. – Diode allows current to pass in only one direction. •A pn-junction diode is formed by joining together n-type and p-type silicon. Let us now turn to the discussion about basic electronic components. The first topic that we will discuss is diodes. A diode is a 2 lead semiconductor that allows current to pass in only one direction. Fig. 3 shows a symbol for a diode and its external view. Fig.3 – Schematic symbols of a diode

Diode: How it Works —I When a diode is connected to a battery as shown, electrons from the n-side and holes from the p-side are forced toward the center by the electrical field supplied by the battery. The electrons and holes combine causing the current to pass through the diode. When a diode is arranged in this way, it is said to be forward biased. We come now to the description of diode operational principle. Let us have a look at Fig.5 which shows a Schematic illustration of a p-n junction. From this figure we see that when a diode is connected to a battery as shown, electrons from the n-side and holes from the p-side are forced toward the center by the electrical field supplied by the battery. The electrons and holes combine causing the current to pass through the diode. When a diode is arranged in this way, it is said to be forward biased. Fig. 5 – Schematic illustration of a p-n junction

Basic electronic components 2. Transistor • A three lead semiconductor device that acts as: – an electrically controlled switch, or – a current amplifier. • Transistor is analogous to a faucet. – Turning faucet’s control knob alters the flow rate of water coming out from the faucet. – A small voltage/current applied at transistor’s control lead controls a larger current flow through its other two leads. Let’s now talk about another semiconductor devices called transistors. In fig 6 we can see that transistor operation is somewhat analogous to a faucet operation in a way that when we turn a faucet’s control knob it alters the flow rate of water coming out from the faucet. The same goes for a transistor. A small voltage/current applied at transistor’s control lead controls a larger current flow through its other two leads. Fig. 6 – Explanation of a transistor operation

Transistor Types: BJT, JFET, and MOSFET Bipolar Junction Transistor (BJT) – NPN and PNP Junction Field Effect Transistor (JFET) – N-channel and P-channel Metal Oxide Semiconductor FET (MOSFET) – Depletion type (n- and p-channel) and enhancement type (n- and p-channel) In this page we can see different types of transistors. There are Bipolar Junction Transistor (BJT), Junction Field Effect Transistor (JFET) – N-channel and P-channel and Metal Oxide Semiconductor FET (MOSFET). Each type of transistor will be discussed in more detail in my future presentations. Fig. 7 - Different types of transistors

Optoelectronics Light emitting diodes Infrared detector In optoelectronics we deal with 2 types of electronic devices. Light emitting electronic devices: ones that generate electromagnetic energy under the action of electrical field. Example: light emitting diodes (visible and infrared light). Light detecting devices: ones that transform electromagnetic energy input into electrical current/voltage. Examples: photoresistors, photodiodes, phototransistors, etc. Now we come to the final part of my presentation. Lets now see what are the optoelectronic devices. In optoelectronics we deal with 2 types of electronic devices. Light emitting electronic devices: ones that generate electromagnetic energy under the action of electrical field. Example are light emitting diodes (visible and infrared light). And Light detecting devices: ones that transform electromagnetic energy input into electrical current/voltage. Examples are photoresistors, photodiodes, phototransistors, etc. Fig. 8 - Examples of optoelectronics devices: LEDs and IR detector

How LED Works • The light-emitting section of an LED is made by joining n-type and p-type semiconductors together to form a pn junction. • When a voltage is applied to the P-N junction, electrons in the n side are excited and move across the pn junction into the p side, where they combine with holes. • As the electrons combine with the holes, photons are emitted. • The pn-junction section of an LED is encased in an epoxy shell that is doped with light scattering particles to diffuse light and make the LED appear brighter. • Often a reflector placed beneath the semiconductor is used to direct the light upward. We come now to the description of LED operation. In Fig. 9 we can see a schematic illustration of LED. It contains and anode and cathode, a reflector and LED chip. This whole structure is protected with an epoxy lens. Lets now have a look at the illustration of LED operational principle shown in Fig.10. What can we see? The light-emitting section of an LED is made by joining n-type and p-type semiconductors together to form a pn junction. When a voltage is applied to the P-N junction, electrons in the n side are excited and move across the pn junction into the p side, where they combine with holes. As a results of electron recombination with the holes, photons are emitted and we see the light. Fig.9 – Schematic illustration of LED Fig.10 – Principle of light generation in p-n junction

Application of LEDs LED uses fall into four major categories: Visual signals where light goes more or less directly from the source to the human eye, to convey a message or meaning. Illumination where light is reflected from objects to give visual response of these objects. Measuring and interacting with processes involving no human vision.[141] Narrow band light sensors where LEDs operate in a reverse-bias mode and respond to incident light, instead of emitting light One more topic remains to discuss. Different applications of LEDs are shown in this page. Here you can see some of the examples where we can used LEDs in our life. Traffic light using LED LED daytime running lights ofAudi A4 LED digital display that can display four digits and points Fig.11 – Examples of LEDs application

Conclusion Depending on electrical conductivity all materials can be divided into three main groups: conductors; insulators and semiconductors Silicon is the most common material used to build semiconductor devices. We have reviewed three main components that are used to build electronic devices, namely: diodes, transistors, LEDs. Now I would just like to sum up the main points again. Depending on electrical conductivity all materials can be divided into three main groups: conductors; insulators and semiconductors Silicon is the most common material used to build semiconductor devices. We have reviewed three main components that are used to build electronic devices, namely: diodes, transistors, LEDs.

Thank you very much for your attention! Now I'd like to invite any questions you may have.