This document discusses semiconductor devices and their characteristics. It introduces P-type and N-type semiconductors, diodes, and their I-V characteristics including forward and reverse bias. Transistors are also introduced as amplifiers that can control current flow. Semiconductor devices are compact, reliable, and low cost components that are widely used in electronics due to their ability to be integrated into complex circuits.

1. Semiconductor Device
BY
ABHA AGRAWAL
DESIGNATION – ASTT. PROFFESSOR
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2. Overview
Introduction
What are P-type and N-type semiconductors??
What are Diodes?
Characteristics Of Diode
I – V Characteristics of Diodes
Diode as Rectifiers
Forward Bias & Reverse Bias
Shockley Equation
Transistors
Transistors as Amplifiers
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3. Introduction
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Semiconductor device, electronic circuit component made from a material that
is neither a good conductor nor a good insulator (hence semiconductor).
Such devices have found wide applications because of their compactness,
reliability, and low cost. As discrete components, they have found use in power
devices, optical sensors, and light emitters including solid-state lasers.

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Examples of Semiconductor Device

5. What are P-type and N-type ?
Semiconductors are classified in to P-type and N-type semiconductor
P-type: A P-type material is one in which holes are majority carriers i.e. they
are positively charged materials (++++)
N-type: A N-type material is one in which electrons are majority charge carriers
i.e. they are negatively charged materials (-----)
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6. Diodes
It is represented by the following symbol, where the arrow indicates the direction of positive
current flow.
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7. Characteristics of Diode
Diode always conducts in one direction.
Diodes always conduct current when “Forward Biased” ( Zero resistance)
Diodes do not conduct when Reverse Biased
(Infinite resistance)
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8. I-V Characteristics of Practical Diode
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9. I-V characteristics of Ideal diode
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10. Forward Bias and Reverse Bias
Forward Bias : Connect positive of the Diode to positive of supply…negative of Diode to negative
of supply
Reverse Bias: Connect positive of the Diode to negative of supply…negative of diode to positive
of supply.
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11. Shockley Equation












 1exp
T
D
sD
nV
v
Ii
q
kT
VT 
Is is the saturation current ~10 -14
Vd is the diode voltage
n – emission coefficient (varies from 1 - 2 )
k = 1.38 × 10–23 J/K is Boltzmann’s constant
q = 1.60 × 10–19 C is the electrical charge of an electron.
At a temperature of 300 K, we have
mV26TV
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12. Rectification
Converting ac to dc is accomplished by the process of rectification.
Two processes are used:
◦ Half-wave rectification;
◦ Full-wave rectification.
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13. Transistors
When a negative voltage is applied to the base (point
B), electrons in the base region are pushed ('like'
charges repel, in this case both negative) back
creating insulation boundaries. The current flow from
point E to point C stops. The transistor's state has
been changed from a conductor to an insulator.
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14. Transistors
The bipolar junction transistor
acts as a current amplifier,
having many applications for
amplification and switching.
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15. Transistors
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16. Unbiased Transistors
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17. Transistors: Amplifier
Apply different values of the
base bias voltage and the
collector bias voltage to the
npn transistor and see
what happens.
With two ammeters (shown as red dots) and a voltmeter to measure VCE we can
determine the characteristics of the transistor.
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18. Transistors: Amplifier
The amount of base current is
determined by the base bias
voltage.
B
C
I
I

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19. Conclusion
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Semiconductor devices have a wide range of current- and voltage-handling
capabilities, with current ratings from a few Nanoamperes (10−9 ampere) to more
than 5,000 amperes and voltage ratings extending above 100,000 volts.
lSemiconductor devices lend themselves to integration into complex but readily
manufacturable microelectronic circuits. They are, and will be in the foreseeable
future, the key elements for the majority of electronic systems, including
communications, consumer, data-processing, and industrial-control equipment.

20. Contact Information
Abha Agrawal
Designation – Astt. Proffessor
Email-Id – abha8024@gmail.com
Advanced Educational Institutions
70 km. Delhi-Mathura Road,
Aurangabad, Distt. Palwal
Haryana, India
01275-302214, 9354260374
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