What makes up a "current" in solid state physics?

[cemtu]

Homework Statement

What makes of a current in solidstate/semiconductor physics?

Relevant Equations

none

If there is some incoming light that has hit electrons of a N-type doped silicon and broke loose these electrons from their covalent bounds and excited them to the conduction band and also excited the electrons in the donor energy level to the conduction band as well, here we know that,

the Majority charge carriers are electrons, so if we apply an external voltage and drive holes(minority charge carriers) and electrons(majority charge carriers) apart and measure the current, does the measured value of current give the value caused by only electrons flowing(majority charge carriers) or the value caused by only holes flowing(minority charge carriers) or value caused by both(amount of electrons(majority) + holes(minority)) of them ??

I am confused.

 

[Delta2]

I am not an expert in semiconductor physics but I think the measured current will be the sum of the two currents from the electrons and the holes carriers.

But let's wait what the experts like @gneill , @jasonRF or @vanhees71 have to say.

 

[vanhees71]

I think that's correct. The "electrons" and "holes" are of course quasiparticles which have the quantum numberes of an electron and a positively charged quasiparticle called "hole". Their effective masses are usually different from the mass of the electron.

 

[cemtu]

I think that's correct. The "electrons" and "holes" are of course quasiparticles which have the quantum numberes of an electron and a positively charged quasiparticle called "hole". Their effective masses are usually different from the mass of the electron.

How can "an absence of electron=hole" has any type of mass?

 

[vanhees71]

Quasiparticles are just an ingenious idea by Landau. You have a many-body system, which you can describe with quantum field theory. Then it turns out that the collective excitations can be described in a formalism which is mathematically identical with the QFT description of particles. Holes are just an excitation of the semiconductor material which behave like such a gas of quasiparticles. Another example are phonons, i.e., the quantized sound waves of a solid. Nowadays the condensed-matter physicists have an entire zoo of all kinds of "exotic" quasiparticles behaving like magnetic monopoles, Weyl fermions, etc.

 

[Gordianus]

Even though it's a rather old book, I like Kittel's simple approach (Introduction to Solid State Physics). He easily explained how "holes" can be thought as "real" objects. Most texts on Electronics resort to this simple picture. Without holes, describing a simple PN junction would be too complex.

 

[cemtu]

Even though it's a rather old book, I like Kittel's simple approach (Introduction to Solid State Physics). He easily explained how "holes" can be thought as "real" objects. Most texts on Electronics resort to this simple picture. Without holes, describing a simple PN junction would be too complex.

I genuinely disagree.

 

[vanhees71]

Why? It's a very successful description.