Current flow in a semiconductor circuit

[CoolDude420]

Homework Statement

Hi,

This isn't a homework question. Just a thought I was having while reviewing some basics.

Let's say I have a DC voltage source. I use two metal wires to connect my DC voltage source across a piece of intrinsic undoped silicon semiconductor. Everything is at room tenperature.

Now, my understanding is that the metal being a very good conductor, will have lots of free electrons that have broken away from their covalent bonds. These electrons are available for conduction and just need a voltage to start moving.

The silicon on the other hand, being a semiconductor, has some electrons at room temperature (not as much as doped silicon) but not nearly as much as the metal.

My question is, why does the silicon limit the current flow (number of electrons) that flow in the circuit. Why can't some of the excess electrons in the metal flow through the silicon lattice and to the other terminal of the battery?

Relevant Equations

N/A

N/A

 

[Steve4Physics]

Homework Statement:: Hi,

This isn't a homework question. Just a thought I was having while reviewing some basics.

Let's say I have a DC voltage source. I use two metal wires to connect my DC voltage source across a piece of intrinsic undoped silicon semiconductor. Everything is at room tenperature.

Now, my understanding is that the metal being a very good conductor, will have lots of free electrons that have broken away from their covalent bonds. These electrons are available for conduction and just need a voltage to start moving.

The silicon on the other hand, being a semiconductor, has some electrons at room temperature (not as much as doped silicon) but not nearly as much as the metal.

My question is, why does the silicon limit the current flow (number of electrons) that flow in the circuit. Why can't some of the excess electrons in the metal flow through the silicon lattice and to the other terminal of the battery?
Relevant Equations:: N/A

N/A

Q1. When carrying a current, is the overall charge on the piece of silicon positive, negative or neutral?

Q2. If 'excess electrons' flowed into the silicon,would the silicon become positive or negative or neutral?

Q3. If the silicon became negatively charged, how would this affect the rate at which electrons enter the silicon?