ENSC 324 HOMEWORK #2 Fall 2015 DUE: Monday, November 9 at 2 PM Please note that unless you show work in the derivations and solutions you will get no credit for the answers. Obviously copied answers from study partners or other sources, etc., will also receive no credit. Please do all parts of all six problems. You may want to make a copy of your homework in case it cannot be returned before Exam 3 (solutions will be provided). Problem #1 An abrupt silicon pn junction at zero bias and T=300K has dopant concentrations of NA = 2×1016/cm3 and ND = 1×1016/cm3 . a) Calculate the Fermi level on each side of the junction with respect to the intrinsic Fermi level. b) Sketch the equilibrium energy band diagram for the junction and determine Vbi from the diagram and the results of part a). c) Now calculate Vbi using Equation (7.10) and compare to the result found in part b). d) Determine xn, xp and the peak electric field for this junction. e) Show how the energy band diagram will change (qualitatively) under both forward and reverse bias on a duplicate of the sketch obtained in part b). What will happen (qualitatively) to the results found in part d) for both forward and reverse bias? Problem #2 We are going to design a GaAs pn junction to meet some certain specifications. The diode is at 300K with a crosssectional area of 10-4 cm2 . At a reverse bias of 4V, we want 20% of the total space charge region width to lie in the p-region and the total junction capacitance to be 0.6 pF. Determine a reasonable set of ND, NA, Vbi, and W to make this diode meet specification. Problem #3 An abrupt silicon pn junction at T=300K under equilibrium conditions has a p-side doping of of NA = 3×1015/cm3 and an n-side doping of ND = 2×1015/cm3 . (i)Compute: a) Vbi b) xn, xp, and W c) the electric field at x=0 d) the voltage at x=0 (ii) Sketch the following as a function of position: a) charge density, b) electric field, electrostatic potential. (iii) Repeat parts (i) and (ii) if everything is kept the same except of NA = 1017/cm3 . Problem #4 An abrupt silicon pn junction diode is to be designed to operate at T = 300K such that the diode current is I = 10 mA at a forward biased diode voltage of 0.75V. The ratio of electron current to hole current is to be 0.1 and the maximum current density is to be no more than 20 A/cm2 . Use the following parameters: NA = ND = 1016/cm3 , Dn = 25 cm2 /s, Dp = 10 cm2 /s, τp0 = τn0 = 0.5 µs, εr = 11.7. Problem #5 A symmetrically doped abrupt silicon pn junction has doping concentration of NA = ND = 5×1016/cm3 . If the peak electric field of in the junction at breakdown is 4 × 105 V/cm, determine the breakdown voltage of the junction. Problem #6 A silicon pn junction diode at T=300K has the following parameters: NA = 5 × 1016 /cm3 , ND = 1 × 1016 /cm3 , Dn = 25 cm2 /s, Dp = 10 cm2 /s, ni = 1.5 × 1010 /cm3 , τn0 = 5 × 10-7 s, τp0 = 1 × 10-7 s, A = 10-3 cm2 . The forward bias voltage is 0.625 V. Find: a) the minority electron diffusion current at the space charge edge; b) the minority hole current at the space charge edge; c) the total current in the pn junction. d) the electron and hole currents at x = xn, x = xn + Lp, and x = xn + 10Lp.
Why Work with Us
Top Quality and Well-Researched Papers
We always make sure that writers follow all your instructions precisely. You can choose your academic level: high school, college/university or professional, and we will assign a writer who has a respective degree.
Professional and Experienced Academic Writers
We have a team of professional writers with experience in academic and business writing. Many are native speakers and able to perform any task for which you need help.
Free Unlimited Revisions
If you think we missed something, send your order for a free revision. You have 10 days to submit the order for review after you have received the final document. You can do this yourself after logging into your personal account or by contacting our support.
Prompt Delivery and 100% Money-Back-Guarantee
All papers are always delivered on time. In case we need more time to master your paper, we may contact you regarding the deadline extension. In case you cannot provide us with more time, a 100% refund is guaranteed.
Original & Confidential
We use several writing tools checks to ensure that all documents you receive are free from plagiarism. Our editors carefully review all quotations in the text. We also promise maximum confidentiality in all of our services.
24/7 Customer Support
Our support agents are available 24 hours a day 7 days a week and committed to providing you with the best customer experience. Get in touch whenever you need any assistance.
Try it now!
How it works?
Follow these simple steps to get your paper done
Place your order
Fill in the order form and provide all details of your assignment.
Proceed with the payment
Choose the payment system that suits you most.
Receive the final file
Once your paper is ready, we will email it to you.
No need to work on your paper at night. Sleep tight, we will cover your back. We offer all kinds of writing services.
No matter what kind of academic paper you need and how urgent you need it, you are welcome to choose your academic level and the type of your paper at an affordable price. We take care of all your paper needs and give a 24/7 customer care support system.
Admission Essays & Business Writing Help
An admission essay is an essay or other written statement by a candidate, often a potential student enrolling in a college, university, or graduate school. You can be rest assurred that through our service we will write the best admission essay for you.
Our academic writers and editors make the necessary changes to your paper so that it is polished. We also format your document by correctly quoting the sources and creating reference lists in the formats APA, Harvard, MLA, Chicago / Turabian.
If you think your paper could be improved, you can request a review. In this case, your paper will be checked by the writer or assigned to an editor. You can use this option as many times as you see fit. This is free because we want you to be completely satisfied with the service offered.