electric field and semiconductors... (1 Viewer)

[gnrlies]

What happens when an electric field is applied accross a semiconductor???

This is refering to the syllabus point:

"perform and investigation to demonstrate a model for explaining the behaviour of semi-conductors, including the creation of a hole or positive charge on the atom that has lost the electron and the movement of electrons and holes in opposite directions when an electric field is applied accross the semi conductor"

The reason why I ask is becuase we have an assignment that asks us to do the following:

"produce a simple model to show the behaviour of semi-conductors when an electric field is applied across the semi-conductor"

 

[underthesun]

for the syllabus point, is it something to do with transistors, or current rectifiers?

i think because of the hole and electron stuff of semi conductors, the {edit:charge carrier} would be carried to one side and vice versa with the holes. But because of the opposing charges, a new electric field will be created, and a new electric field will be created and it would cancel the old one, and an equilibrium is established..

that is, if there are no wires attached (as in conducting wires) for a circuit. Then the holes and the electrons would be limited on near the edges.

purplish hue syllabus notes didn't mentioned about the equilibrium and the electric field. I think that part has more to do with solar cells.

 

[jims]

i tihnk for this prac we had a line of MMs and pretended that there was an electric field along it. 1 electron would move towards the postive plate (ie forward 1 spot) leaving a gap (hole). this would attact the next electron and so on. it was really quite useless because its not exactly hard to just imagine it all in ur head. plus i dont think this is a particularly good model

 

[Giant Lobster]

lol@mm model

hmm I think underthesun is right about the opposing electric fields and equilibrium. But you didnt make it clear as to whether it was for rectifying current direction. Because if it were, I think you have to describe in detail how the direction of the electric field affects the overall behaviour of the semiconductor, and mention depletion zones. i.e. -ve N-P +ve = current flow while +ve N-P -ve = increased resistance due to depletion zone widened.

Maybe that wasnt quite helpful... I didnt quite understand ur question sorry