n-type doping question (1 Viewer)

[124]

Hi, if adding group 3 such as boron and make it p-type it will become more conductive because more free positively charged holes.

What if add group 5 such as phosphorus more free electrons what happens with the conductivity?

Thanks in advance

 

[RishBonjour]

more free electrons--> more conductive.

 

[deswa1]

N type-> more electrons -> get added to a donor level right below the conduction band -> the energy gap between this and conduction band is tiny so very small amounts of thermal energy allow promotion to conduction band where they conduct-> therefore greater conductive properties.

Two very important things:
1. N type semiconductors are NOT negatively charged, they are still neutral.
2. Positive holes still carry charge like an intrinsic conductor, its just that electrons become the primary charge carriers

 

[deswa4]

N type-> more electrons -> get added to a donor level right below the conduction band -> the energy gap between this and conduction band is tiny so very small amounts of thermal energy allow promotion to conduction band where they conduct-> therefore greater conductive properties.

Two very important things:
1. N type semiconductors are NOT negatively charged, they are still neutral.
2. Positive holes still carry charge like an intrinsic conductor, its just that electrons become the primary charge carriers

This is such a perfect response!

 

[124]

So what is the difference in conductivity for p-type and n-type? Is it n-type has a donor level to store more electrons but p-type has acceptor level

 

[Shadowless]

this is such a perfect response!

who are you?

 

[deswa4]

who are you?

Who are you?

 

[dawooddaman]

Who are you?

Bob?

 

[someth1ng]

For p-type, there are positive "holes" charge carriers in the valence band that is able to move and hence, decrease resistivity. In n-type, there are excess in negative electrons which are in the conduction band and hence, decrease resistivity.

Note: doping doesn't necessarily decrease resistivity - it applies in this case but not always true for all semiconductors.