# Current flow in a semiconductor circuit

• CoolDude420
In summary, the conversation discusses the behavior of a DC voltage source connected to a piece of intrinsic undoped silicon semiconductor. The metal wires, being good conductors, have lots of free electrons that are available for conduction with the help of a voltage. On the other hand, the silicon, being a semiconductor, has fewer free electrons at room temperature. The conversation poses questions about the overall charge of the silicon when carrying a current, the effect of excess electrons on the silicon's charge, and how a negative charge on the silicon would affect the rate of electron flow.

#### 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

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?

## 1. What is a semiconductor circuit?

A semiconductor circuit is a type of electronic circuit that uses semiconductor materials, such as silicon, to control the flow of electric current. These circuits are widely used in electronic devices, including computers, smartphones, and televisions.

## 2. How does current flow in a semiconductor circuit?

In a semiconductor circuit, current flows through the material in a controlled manner. This is achieved by creating a depletion region, where the concentration of positively and negatively charged particles is different, using a process called doping. By applying a voltage to the circuit, the flow of current can be controlled through this depletion region.

## 3. What is the role of diodes in a semiconductor circuit?

Diodes are a type of semiconductor device that allow current to flow in only one direction. They are commonly used in semiconductor circuits to rectify alternating current (AC) into direct current (DC). Diodes also play a crucial role in regulating voltage levels within a circuit.

## 4. How does temperature affect current flow in a semiconductor circuit?

The flow of current in a semiconductor circuit is highly dependent on temperature. As temperature increases, the number of charge carriers (electrons and holes) in the material also increases, leading to a higher current flow. However, at very high temperatures, the semiconductor material may become damaged and hinder the flow of current.

## 5. What are the advantages of using semiconductor circuits?

Semiconductor circuits offer several advantages over other types of circuits, such as vacuum tube or mechanical circuits. These include smaller size, lower power consumption, higher reliability, and faster switching speeds. Additionally, semiconductor materials are abundant and relatively inexpensive, making them a cost-effective choice for electronic devices.

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