EE 5621

PROBLEM SET 1

S. G. Burns

Due: 17 September (Friday) 2021

Ø Unless otherwise announced, I will collect the problem set when I collect the associated quiz. It is also important to note that I often use homework problems as part of the weekly quizzes. Quiz coverage will include material related to, and supporting, the problem set as well as material covered in class through the previous class period material. Any additions or deletions from quiz topical coverage will be announced in class, via e-mail, and/or on the class WEB page. I strongly encourage you to ask questions about the homework problems during class and during ZOOM office visits. I also encourage you to ask for assistance on any underlying and supporting topics from other courses. You may work together, and I encourage you to do so, but remember you, and you alone, are responsible for your work and you must turn in homework individually unless otherwise noted.

Ø ALL QUIZZES are open book and notes. Laptops and tablets are OK as well as WEB access. Be careful of time management when you surf the WEB.

Ø Be sure and bring your completed problem set to class.

Ø QUIZ 1, nominally 25 minutes long, will be given on Friday, 17 September, during the last portion of the class period.

Ø Also, take the opportunity to study the text "Examples", which includes solutions.

Ø I also strongly encourage that you read Chapters 1 and 2 to provide a broad perspective on what topics are included in the text.

Ø One other issue which you should be aware of. I use SYMBOL font in MSWORD, and ADOBE fonts, as needed, in preparing WEB documents. For better or worse, I also use IE and Chrome as my WEB browsers. One reason I use MS WORD and IE and Chrome is that they are available at no cost through ITSS for students and faculty. There are cases where your personal WEB browser and word processing program may not interpret SYMBOL font correctly. This is especially true for “shareware” and non-standard versions of word processing programs and versions of some WEB browsers such as Firefox. For example the micrometer symbol for 10^{-6 which} should print out as the Greek symbol μ could print out as an “m” which is 10^-3. This would occur if your printer driver and/or word processing and/or font utility within your WEB browser were not set up to accept SYMBOL, or in some cases ADOBE fonts. To the best of my knowledge, all the EE computers (and any other university WINDOWS computers) using IE and MS products and printers are OK but your personal system may not be. Please let me know if you have this difficulty so I can try and work on fixes with you.

Lots of basic plug-and-chug

1. StanBurnsium is a very rare and important crystal with 12 atoms/unit cell and a lattice spacing of 5.5 . Compute the volume density and compare your results numerically with the volume density of GaAs. Both answers must be in cgs units.

2.

z or c

Compute the Miller indices for the crystal plane shown in the figure.

3. One of your friends, attending at a large university in the Twin Cities, wants to dope a Si wafer with 2 x 10²³ boron atoms/cm³. Briefly explain why this student is probably doing very poorly in their equivalent EE 5621 course.

4. Compute the majority and minority charge carriers at 300K if:

(a) ND = 3 x 10¹⁷ cm^-3

(b) NA = 3 x 10¹⁷ cm^-3

(c) Determine the electron and hole mobilities and resistivities for both Parts (a) and (b). I suggest using graphical results one can find on the WEB or perhaps in previous course notes.

5. Be sure you make the conversion from eV to joules or your answer will be incorrect by a factor of 1.602 x 10^-19, which is significant! Electron volts (eV) is almost universally used in the semiconductor world for energy rather than Joules. Before we had flat panel television screens, cathode ray picture tubes (CRTs) were used. CRT televisions were discontinued 10+ years ago although you still might have one buried in your basement. The operating principle was that 20 keV electrons impacted the either the red, green or blue phosphor dots or rectangles on the screen creating the RGB the image. These 20 keV electrons have an associated energy upon impact which produce photons with a wavelength given by __________________(Fill in the blank). Consequently, what was the safety issue associated with the wavelength of these photons and what material was added to the glass envelope to improve safety even if you sat too close to the television? Briefly explain.

56. Some plug and chug using Plannck’s constant.

(a) Compute the range of photon energies in eV over the visible spectrum.

(b) Did you know that the three photoreceptors of the honeybee (Menzel and Backus, 1991) peak at 344 nm, 436 nm, and 556 nm? Compute the photon energy at each wavelength and what would a human observe for each wavelength?