Explain temperature dependency in semiconductors, Electrical Engineering

Assignment Help:

Explain temperature dependence of electrical resistivity and conductivity in semiconductors.

The electrical conductivity of the semiconductors changes considerably with temperature changes. At absolute zero, this behaves as an insulator. And at room temperature, due to thermal energy, several of the covalent bonds of the semiconductor break. The breaking of bonds sets those electrons free that are engaged in the formation of such bonds. It results in few free electrons. All these electrons constitute a small current if potential is applied across the semiconductor crystal. It demonstrates the conductivity for intrinsic semiconductor increases along with increase in temperature as specified by η=A exp(-Eg/2kT), here η is the carrier concentration, T is the temperature, Eg is the energy band gap and A is constant. If in extrinsic semiconductors, addition of small amount of impurities creates a large number of charge carriers. That number is so large that the conductivity of an extrinsic semiconductor is a lot of times more than an intrinsic semiconductor at the room temperature. In n-type semiconductor each donor has donated their free electrons at room temperature. The additional thermal energy only serves to raise the thermally generated carriers. It increases the minority carrier concentration. A temperature is reached while the number of covalent bonds which are broken is so large which the number of holes is almost equal to the number of electrons. After that the extrinsic semiconductor behaves as intrinsic semiconductor.


Related Discussions:- Explain temperature dependency in semiconductors

Successive approximation adc, Successive approximation ADC One method ...

Successive approximation ADC One method of addressing digital ramp ADC's shortcomings is so-called successive approximation ADC. Only change in this design is a very special c

Cause of sparking at the brushes of a dc motor, Q. Cause of sparking at the...

Q. Cause of sparking at the brushes of a DC Motor? Ans: Sparking at the brushes can be occur due to poor quality of carbon brushes, loose connection, poor armature of carbon

Flip flops, if JK flip flop has 1600hz frequency .then what is the input fr...

if JK flip flop has 1600hz frequency .then what is the input frequency?

Name the materials used in case of bimetals, Name the materials used in cas...

Name the materials used in case of Bimetals and give reasons. Bimetals : Alloy of nickel and iron along with low value of coefficient of thermal expansion are utilized as

Realize various dividers in the schematic representation, Q. Counters are u...

Q. Counters are used to realize various dividers in the schematic representation of the digital clock shown in Figure. The blocks labeled "logic array" are logic gate combinations

What are loosely coupled systems, What are loosely coupled systems? In ...

What are loosely coupled systems? In loosely coupled systems every CPU may have its own bus control logic. The bus arbitration is handled by an external circuit, common to all

Sketch the phasor diagram showing all the voltages, Q. A balanced wye-conne...

Q. A balanced wye-connected load with a per-phase impedance of 4 + j3  is supplied by a 173-V, 60-Hz three-phase source. (a) Find the line current, the power factor, the total

Explain the fixed bias circuit, Q. Explain the fixed bias circuit?     ...

Q. Explain the fixed bias circuit?           The Fig refers to the common emitter collector characteristics and the ac and dc load lines.The Fig shows the points Q 1 and Q 2

Write Your Message!

Captcha
Free Assignment Quote

Assured A++ Grade

Get guaranteed satisfaction & time on delivery in every assignment order you paid with us! We ensure premium quality solution document along with free turntin report!

All rights reserved! Copyrights ©2019-2020 ExpertsMind IT Educational Pvt Ltd