modelling conductors, semiconductors and insulators (1 Viewer)

[delorean]

i have an assigment involving modelling conductors, semiconductors and insulators, how they work etc.

i dont really get how they work in the first place though my textbook isnt very clear.

could someone explain to me in human language how they work and what they do? the movement of electrons in a semiconductor when theres an electric field across it? all that stuff.. please just so i actually have a clear idea of what im going to model.

thanks in advance!

 

[rama_v]

If you were doing it properly, you would use the Drude model for conductivity in metals. Then, you would use the nearly-free electron model (probably simpler than other models IMO) for semiconductors. That would give you an overview of band theory and concepts such as effective mass, drift velocity, holes, direct and indirect band gaps, etc. All of which are beyond the scope of the present syllabus.

However, seeing as this is HSC physics, they probably are simple asking you to draw two bands and say for metals the conduction band 'overlaps' with the valence band, and for semiconductors there is no overlap, etc. And, at the end of the day, you learn nothing about why bands even exist in the first place, and why on earth there is a gap at all...

 

[Aerath]

LOL, ours was really lame - just had pens as the 'barriers' between the different energy bands, and used marbles as 'electrons', and then we watched them 'jump' over/into/across the 'gap'.