How Fast Do Electrons Drift in a Silicon Resistor?

In summary: The total current is the sum of all currents. In summary, the problem asks for the drift velocity of electrons in an Si resistor at 300Kelvin, with dimensions of 100μm long, 1μm thick, and 5μm wide, and a voltage of 5v applied. Given that the electron concentration is n = 1.01x103, we can use the formula Jn,drift = qn(μnE) to find the drift current. However, we need to determine the electric field (E) first. This can be done by using the formula E = V/L, where V is the voltage and L is the length of the resistor. Using this, we can find the
  • #1
de1337ed
11
0
Problem:

An Si resistor is at 300Kelvin, and is 100μm long, 1μm thick, 5μm wide. The conductivity is 7.128 Ωcm. The resistance is 28058Ω. A voltage of 5v is applied. What is the drift velocity of the electrons, given that n = 1.01x103?
Other constants:
μn = 1350 cm2/Vsec
μp = 450 cm2/Vsec
---
My work:
So basically,
I have the formula Jn,drift = qn(μnE).
The question asks for drift velocity, does that mean I'm trying to find Jn,drift or just the mobility factor μnE? What exactly is Jn,drift? In either scenario, how do I find E field if I'm only given a voltage? It's not like I can integrate b/c Voltage is constant through the resistor.
I was also considering using I = nqvdA. But I was getting some outrageous velocity with this.
Ideas?
Thank you.
 
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  • #2
de1337ed said:
Problem:

An Si resistor is at 300Kelvin, and is 100μm long, 1μm thick, 5μm wide. The conductivity is 7.128 Ωcm. The resistance is 28058Ω. A voltage of 5v is applied. What is the drift velocity of the electrons, given that n = 1.01x103?
Other constants:
μn = 1350 cm2/Vsec
μp = 450 cm2/Vsec
---
My work:
So basically,
I have the formula Jn,drift = qn(μnE).
The question asks for drift velocity, does that mean I'm trying to find Jn,drift or just the mobility factor μnE? What exactly is Jn,drift? In either scenario, how do I find E field if I'm only given a voltage? It's not like I can integrate b/c Voltage is constant through the resistor.
I was also considering using I = nqvdA. But I was getting some outrageous velocity with this.
Ideas?
Thank you.

Jn,drift is probably the drift current of negative carriers (electrons). In a semiconductor you may have also drift current of holes as well as diffusion currents of both types of carriers.
 

1. What is drift velocity in a resistor?

Drift velocity in a resistor is the average velocity at which electrons move through the material of the resistor when a potential difference is applied across it.

2. How is drift velocity related to current?

Drift velocity is directly proportional to the current in a resistor. This means that as the current increases, the drift velocity of the electrons also increases.

3. What factors affect the drift velocity in a resistor?

The drift velocity in a resistor is affected by the material of the resistor, the temperature, and the strength of the applied electric field. Higher temperatures and stronger electric fields can result in higher drift velocities.

4. How does drift velocity affect the resistance of a material?

Drift velocity is one of the factors that determine the resistance of a material. As the drift velocity increases, the resistance decreases, and vice versa.

5. Can drift velocity be measured?

Yes, drift velocity can be measured using various experimental methods. One common method is by measuring the current and potential difference across a resistor and using Ohm's law to calculate the drift velocity. Other methods include using a Hall effect sensor or a cathode ray tube.

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