Current flow in a semiconductor circuit

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SUMMARY

The discussion centers on the current flow in a semiconductor circuit, specifically focusing on intrinsic undoped silicon connected to a DC voltage source via metal wires. It is established that while metals have a high density of free electrons facilitating conduction, intrinsic silicon has significantly fewer free charge carriers at room temperature. This disparity in electron availability limits the current flow through the silicon, as excess electrons from the metal cannot easily traverse the silicon lattice due to its semiconductor properties. The questions posed explore the charge dynamics within the silicon when current flows and the implications of charge accumulation on electron movement.

PREREQUISITES
  • Understanding of semiconductor physics, specifically intrinsic silicon behavior
  • Knowledge of electrical conduction mechanisms in metals and semiconductors
  • Familiarity with basic concepts of charge carriers (electrons and holes)
  • Awareness of the effects of temperature on semiconductor conductivity
NEXT STEPS
  • Research the differences between intrinsic and doped silicon conductivity
  • Learn about the role of temperature in semiconductor charge carrier dynamics
  • Explore the concept of charge neutrality in semiconductor materials
  • Investigate the effects of electric fields on electron movement in semiconductors
USEFUL FOR

Students of electrical engineering, semiconductor physicists, and anyone interested in understanding the fundamentals of current flow in semiconductor devices.

CoolDude420
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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
 
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CoolDude420 said:
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?
 

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