Classify the materials based on the energy bands, Electrical Engineering

Assignment Help:

Classify the materials based on the energy bands and explain them.

Classification of materials based on energy bands:

With reference to various band structures demonstrated in figure below we can generally divide solid in semiconductors, insulators and conductors. Conductors have many of electrons in the conduction band at room temperature. There no energy gaps exist and the valence and conduction bands overlap.

312_energy bands.png

Insulator is a material wherein the energy gap is too large that practically no electron can be given sufficient energy to jump that gap.

These materials might conduct little electricity when their temperature is raised to very high values enabling some electrons to join the conduction band. A semiconductor is a solid along with an energy gap small sufficient for electron to cross simply from the valence band to the conduction bands. At room temperature adequate energy is available for valence electrons to bridge the energy gap to the conduction band; therefore the material sustains a few electric current.

The energy distribution of electrons in a solid are governed through the laws of Fermi - Dirac statistics.

The Fermi level is that at any temperature, the no. of electrons along with greater energy than the Fermi energy is equivalent to the number of unoccupied energy levels lower than it. In conductors, the Fermi level is put in a permitted band because the valence band and conduction band overlap with no energy gap. In insulators, this lies in the centre of the large energy gap whereas in semiconductors this lies in the relatively small energy gap.


Related Discussions:- Classify the materials based on the energy bands

Determine the peak fundamental component of the mmf, Q. A two-pole, three-p...

Q. A two-pole, three-phase synchronous generator has a balanced three-phase winding with 15 turns per phase. If the three-phase currents are given by i a = 100 cos 377t, i b =

Obtain rated fundamental voltage across the motor, A 440-V, 60-Hz, six-pole...

A 440-V, 60-Hz, six-pole, wye-connected, squirrel-cage induction motor with a full-load speed of 1170 r/min has the following parameters per phase referred to the stator: R 1 = 0.

Sketch voltage and the energy stored in the capacitor, Q. Considering the c...

Q. Considering the circuit shown in Figure, sketch v(t) and the energy stored in the capacitor as a function of time.

Calculate the pay back of the project, Problem: Jyoti Textile is consid...

Problem: Jyoti Textile is considering whether to add a new product to its range. Machinery costing $280,000 would have to be bought at the start of the project (Year 0). The pr

Show television waveform, Q. Show television waveform? The television w...

Q. Show television waveform? The television waveform representing one scan is illustrated in Figure. A blanking pulse with a duration of 0.18 of the horizontal - sweep period T

Assinment, Ask question #Minimum mechanism of microwave communication 100 w...

Ask question #Minimum mechanism of microwave communication 100 words accepted#

Harmonics, how harmonics shows effect on power systems?

how harmonics shows effect on power systems?

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