Explain einstein relation, Electrical Engineering

Assignment Help:

Explain Einstein relation.

Einstein relation:

There exists a significant relation between the diffusion constant and the mobility. It is termed as the Einstein relation and may be deduced as given below:

Consider a semiconductor wherein there exists an electric field Ex and a concentration gradient as the current is zero. In these conditions the system is in the Boltzmann statistics and thermal equilibrium applies. Consider a potential V(x) producing at x an electric field E(x)= -dV/dx.

For the density of holes the Boltzmann expression as a function of x in thermal equilibrium is as

p(x) = Ce-eV/KT

Here C is a constant.

Therefore the gradient of the hole density is given by

dp/dx = (-e/KT)p.(dv/dx)

= (e/KT)p.E

The hole current vanishes in thermal equilibrium. Therefore,

O=peup Ex-eDp  dp/dx

=peup Ex-(e2 /KT)Dp . Ex

Dp = (KT/e) Up (i.e. the Einstein relation).


Related Discussions:- Explain einstein relation

Define resistance in lumped-circuit, Q. Define Resistance in lumped-circuit...

Q. Define Resistance in lumped-circuit? An ideal resistor is a circuit element with the property that the current through it is linearly proportional to the potential differenc

Sketch the waveform of the circuit , The following four output displays of ...

The following four output displays of an oscilloscope (right hand side, below) show waveforms of a biased diode ac circuit. An example is illustrated on the left hand side. VIN is

Standard color-coded bands for evaluating resistance, Standard Color-Coded ...

Standard Color-Coded Bands for Evaluating Resistance Practical resistors are manufactured in standard values, various resistance tolerances, several power ratings (as will be e

Name the effects of electric current, Name the Effects of electric current ...

Name the Effects of electric current There are three Effects of electric current:- A) magnetic effect B) chemical effect C) heating effect

Working of r digital to analog converter, 2 n -R D/A CONVERTER An n-bit...

2 n -R D/A CONVERTER An n-bit 2 n -R D/A converter needs 2 n resistors of equal value R and (2 n+1 -2) analog switches. A 3-bit 2 n -R D/A converter is shown in Figure, which

Dc machines, a 400V 4-pole DC generator takes an armature current of 50A wh...

a 400V 4-pole DC generator takes an armature current of 50A when rotating at 626 rpm. the armature circuit resistance is 0,25ohms. determine the generated emf. DOC

Complete the timing diagram for counter, Q. When the J and K inputs of a JK...

Q. When the J and K inputs of a JKFF are tied to logic 1, this device is known as a divide-by-2 counter. Complete the timing diagram shown in Figure for this counter.

Selection of right- flex in electricity and gas hazards, Selection of Right...

Selection of Right- Flex : It is also important that the flex we choose is appropriate to the appliance used. Like fuses, the cables and flexes are also rated according to their

Distribution loss reduction and efficiency improvement, Distribution Loss R...

Distribution Loss Reduction and Efficiency Improvement You are well aware of the fact in which all energy supplied to a distribution utility does not reach the end consumers.

Explain modulation and sampling, Q. Explain Modulation and sampling? Mo...

Q. Explain Modulation and sampling? Modulation is the process whereby the amplitude (or another characteristic) of a wave is varied as a function of the instantaneous value of

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