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5 lessons,
48m 59s
Course Overview and Electron and Holes
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In this lesson i introduced regarding electron holes and there movement in bands

Rupali kanwar
I am a socialist from age of 15. I believe in sharing knowledge across the world. on unacademy I will teach regards women and women power

Unacademy user
sir please make minimum 60 minutes video

  2. Effective Mass of electrorn Concept of Holes Energy Band Structure of Solids: Conductors, Insulators and Semiconductors Band Theory .Semiconductors Intrinsic and ExtrinsicSemiconductors Type of diodes Simple Diode Zener Diode

  3. Effective Mass of electron An electron moving in the solid under the influence of the crystal potential is subjected to an electric field. We expect an external field to accelerate E and k and change the electron, increasing Electronic state. 4-k at time , later k at start

  4. and d dt dt dr dt de dkd dk dt dk dV dt dx

  5. 1 de (dk

  6. Concept of Holes Consider a semiconductor with a small number of electrons excited from the valence band into the conduction band rIf an electric field is applied, the conduction band electrons will participate in the electrical current the valence band electrons can ove iYto the empty states, and thus can also contribute to the curren

  7. Concept of Holes If we describe such changes via "movement" of the "ei"pty" states the picture will be significantly simplified. This "empty space" is called a Hole. "Deficiency" of negative charge can be treated as a positive charge. Holes act as charge carriers in the sense that electrons from nearby sites can "move" into the hole. Holes are usually heavier than electrons since they depict collective behavior of many electrons.

  8. o electrons holes Energy Conduction band Narrow forbidden gap Valence band Applied E field

  9. To understand hole, motion, one requires another view of the holes, which represent them as electrons with negative effective mass m* For example the movement of the hole think of a row of chairs occupied by people with one chair empty, and to move all people rise all together and move in one direction, so the empty spot moves in the same direction

  10. Energy Band Structure of Solids Conductor, Semiconductor and Insulator In isolatedatoms electrons are arranged in energy levels.b Nucleus, containing positively charged protons Orbital electrons, negatively charged