Calculating Drift Velocity in Pure Silicon: Need Help

Thread starter becon
Start date Dec 29, 2010
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Drift Drift velocity Velocity

In summary, the drift velocity in pure silicon can be calculated using the formula: vd = (q * E * tau) / m*, where vd is the drift velocity, q is the charge of an electron, E is the electric field, tau is the material's relaxation time, and m* is the effective mass of the charge carrier in silicon. The relaxation time in pure silicon is the average time between collisions of charge carriers with impurities, defects, or other particles in the material. It is a key parameter in calculating drift velocity and can vary depending on the purity and temperature of the silicon. The electric field plays a crucial role in determining the drift velocity in pure silicon, as it increases the force on the charge carriers and can result

Dec 29, 2010

becon

I have a small question that can't solve.
How long does it take an average electron to drift 1um in pure silicon in an electric field of 10^4 V/m ?

drift velocity v_d = I / (n*q*A)
but don't know how to calculate
can you help me ?
thank you.

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Dec 29, 2010

ehild

Homework Helper

The drift velocity is mobility times electric field strength.

Google the "mobility of electron in silicon".

ehild

FAQ: Calculating Drift Velocity in Pure Silicon: Need Help

1. How is drift velocity calculated in pure silicon?

The drift velocity in pure silicon can be calculated using the formula: vd = (q * E * tau) / m*, where vd is the drift velocity, q is the charge of an electron, E is the electric field, tau is the material's relaxation time, and m* is the effective mass of the charge carrier in silicon.

2. What is the relaxation time in pure silicon?

The relaxation time in pure silicon is the average time between collisions of charge carriers with impurities, defects, or other particles in the material. It is a key parameter in calculating drift velocity and can vary depending on the purity and temperature of the silicon.

3. How does the electric field affect drift velocity in pure silicon?

The electric field plays a crucial role in determining the drift velocity in pure silicon. As the electric field increases, the force on the charge carriers also increases, resulting in a higher drift velocity. However, at high electric fields, the velocity may reach a saturation point due to collisional processes.

4. What is the effective mass of charge carriers in silicon?

The effective mass in silicon is a measure of the mass of an electron or hole in the material when it is subjected to an external electric field. In pure silicon, the effective mass of the charge carriers is determined by the crystal structure and can vary depending on the direction of the electric field.

5. How can I experimentally measure drift velocity in pure silicon?

There are several methods for experimentally measuring drift velocity in pure silicon. One common approach is to use Hall effect measurements, where an electric field is applied perpendicular to the direction of current flow and the resulting voltage is measured. Other techniques include time-of-flight measurements and transient photocurrent measurements.