Question

1) You have the following scenario: • An electric field points from left to right (along the +x axis) • The electron density decreases as the x-coordinate increases • The hole density decreases as the x-coordinate increases. What are the directions of (Your answer should be either left-to-right or right-to-left or no current.): (a) Electric current carried by electrons (b) Electric current carried by holes 2) By looking at the literature find the mobility of electrons in bulk (a) Silicon, (b) Germanium and (c) Gallium Arsenide. If you were to make a high speed device, which material would be best and why? Ignore cost of fabrication and assume the same operating voltage for all devices. 3) An electron in Germanium (or for that matter any solid) cannot accelerate indefinitely in an external electric field. Why?

Can I get please some of or all of the above questions answered. I appreciate for the help. Thumbs are there to give

Answer 1

Attaching the solution .

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There are two different types of current is semiconductors, 0 Dreift cerent @ Diffusion evrent. 0 carriet drift results when an electric field E is applied across a piec of stucon . The electric field accelerates the holes in the dixection and electrons en the direction opposite to E. These two cerre components add together to produce a drift current in RE carrier diffusion occurs when the concentration of charge carro made higher in one part of the silicon crystal than in other Griven, Electric field E tvex direction. (Left to right) electrons move opposite to Electric field (E). ( right to @ Eleetric current carried by electone 6 Electric current by holes (left to right). 1 (Right to left) ☺ Mobility of electron is bulk és : (a) Silicon = 1300 Chaſsee o Germanicems 3800 cm/usee @ Gallium Arsenide = 5600-8500 confuse. Gallium Aresenide (Gats) is the best switching material be @ show teenneling effect 6 Property of Negative resistance (3) Electron cannot accelerate indefinetely because inside every material, there will be collision between the oloms and therefore scattering and deaccleration,