How Fast Do Electrons Drift in a Silicon Resistor?

AI Thread Summary
The discussion revolves around calculating the drift velocity of electrons in a silicon resistor under specific conditions. The user is confused about whether to find the drift current density (Jn,drift) or the mobility factor (μnE) and how to determine the electric field (E) from the given voltage. Clarification is provided that Jn,drift refers to the drift current of electrons, and the complexities of semiconductor behavior, including the presence of hole currents and diffusion, are acknowledged. The user also considers using the current formula, I = nqvdA, but encounters unrealistic velocity results. The conversation highlights the challenges in applying fundamental equations to semiconductor physics.
de1337ed
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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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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.
 

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