Semiconductor Devices: Homework Solution

[fudawala]

Homework Statement

For a forward biased P plus N abrupt junction diode, Lp = 1 micrometer, and at x = xn (x' = 0), the ratio of the hole current to the electron current, Ip/In, is 100 in the steady state. Determine Ip/In at x' = 1 micrometer.

Homework Equations

Jn = In/A

Jp = Ip/A

Jp(x') = qDpp0n/Lp[exp(qVa/KT) - 1]exp(-x'/Lp)

Jn(-xp) = qDnnop/Ln[exp(qVa/KT) - 1]

The Attempt at a Solution

The attempt to the solution was to use the relationship of the second equation which is the hole current density equation. I have manipulated the equation to solve for the hole current which is Ip = AJp. This is where I got stuck and I could not finish the problem.

 

[KataKoniK]

Thank you for your post. After looking at the equations and information provided, I believe the following steps can help you solve the problem:

1. Use the given information to calculate the electron current density at x = xn (x' = 0). This can be done using the equation Jn = In/A, where A is the area of the diode. Note that In is the total electron current, so you will need to use the ratio of Ip/In to determine the hole current at x = xn.

2. Use the given equation for Jp(x') to calculate the hole current density at x' = 1 micrometer. Note that you will need to use the same area A for both Jn and Jp.

3. Use the equation Jp = Ip/A to solve for the hole current Ip at x' = 1 micrometer.

4. Finally, use the calculated values for In and Ip to determine the ratio of Ip/In at x' = 1 micrometer.

I hope this helps. Let me know if you have any further questions.

 

[Mene]

it is important to recognize when you have reached a roadblock in solving a problem and to seek out additional resources or assistance. It may be helpful to consult with a colleague or conduct further research on the topic. Additionally, it may be beneficial to review any relevant equations or concepts to ensure a complete understanding of the problem. In this case, it may also be helpful to consider the properties of a forward biased diode and how the current is affected by changes in x'. By understanding the behavior of the diode, you may be able to apply the equations and solve for the desired ratio.