Current Flow in Semiconductors and Conductors

Learn about the flow of current in semiconductors, including intrinsic, n-type, and p-type materials, as well as in conductors. Understand how free electrons and holes contribute to current in different materials, and the factors affecting electron movement.

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Questions and Answers

What is the primary cause of current flow in a semiconductor?

Electron and hole flow

In a semiconductor, what is the effect of applying a voltage across it?

Free electrons move towards the positive side

What is drift velocity in a semiconductor?

Finite steady velocity of electrons under steady state conditions

What does mobility refer to in a semiconductor?

The ability of charged carriers to move throughout the material Signup and view all the answers

How is drift velocity computed in a semiconductor?

$vd = rac{ ext{mobility} imes E}{V}$ where $E$ is electric field intensity (V/m) Signup and view all the answers

What is the primary difference between an n-type and a p-type semiconductor?

The presence of free electrons in n-type and absence in p-type Signup and view all the answers

What is the concentration of free electrons in the material?

7.8x10^11 electrons/cm3 Signup and view all the answers

What is the concentration of holes in the material?

7.8x10^11 holes/cm3 Signup and view all the answers

Based on the carrier concentrations, does the material behave as p or n type?

n type Signup and view all the answers

What is responsible for diffusion current in semiconductors?

Non-uniform concentration of charged carriers Signup and view all the answers

Under what conditions can diffusion current exist in a semiconductor?

Even in the absence of an electric field Signup and view all the answers

Which factors are diffusion constants for holes and electrons directly proportional to?

Electron and hole mobility, and temperature Signup and view all the answers

What is the equation for drift current density in a semiconductor?

I = Jn + Jp Signup and view all the answers

What is the formula for conductivity of intrinsic semiconductor?

σi = (ni mn + ni mp)q Signup and view all the answers

What does the number of donor impurity atoms per unit volume represent in n-type semiconductor conductivity equation?

ND Signup and view all the answers

Which parameter greatly influences the conductivity of p-type semiconductor?

Hole concentration (pp) Signup and view all the answers

How is the conductivity of semiconductor computed in terms of electron and hole mobility?

( ND mn)q Signup and view all the answers

What property significantly differs between Ge and Si based on the atomic structure table?

(ni) Intrinsic carrier concentration Signup and view all the answers

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