# Site Feedback **URL:** https://forum.solidstate.quantumtinkerer.tudelft.nl/c/site-feedback/2.md [Latest](https://forum.solidstate.quantumtinkerer.tudelft.nl/latest.md) · [Categories](https://forum.solidstate.quantumtinkerer.tudelft.nl/categories.md) · [Tags](https://forum.solidstate.quantumtinkerer.tudelft.nl/tags.md) --- ## [About the Site Feedback category](https://forum.solidstate.quantumtinkerer.tudelft.nl/t/about-the-site-feedback-category/1)
**Author:** [@system](https://forum.solidstate.quantumtinkerer.tudelft.nl/u/system)\ **Replies:** 1\ **Last updated:** [May 14, 2026, 11:46am UTC](https://forum.solidstate.quantumtinkerer.tudelft.nl/t/about-the-site-feedback-category/1 "2026-05-14T11:46:33Z")
--- ## [Exam grades](https://forum.solidstate.quantumtinkerer.tudelft.nl/t/exam-grades/3867)
**Author:** [@r.t.debrouwer](https://forum.solidstate.quantumtinkerer.tudelft.nl/u/r.t.debrouwer)\ **Replies:** 1\ **Last updated:** [June 8, 2026, 8:35am UTC](https://forum.solidstate.quantumtinkerer.tudelft.nl/t/exam-grades/3867 "2026-06-08T08:35:57Z")
Is there any information on when we get the grades for the final exam? In respect to the fact we have the retake in 2 weeks and 2 days, meaning we have to make the choice for the retake soon. --- ## [Solutions of the minitests](https://forum.solidstate.quantumtinkerer.tudelft.nl/t/solutions-of-the-minitests/3832)
**Author:** [@m.singh-9](https://forum.solidstate.quantumtinkerer.tudelft.nl/u/m.singh-9)\ **Replies:** 1\ **Last updated:** [May 18, 2026, 12:50pm UTC](https://forum.solidstate.quantumtinkerer.tudelft.nl/t/solutions-of-the-minitests/3832 "2026-05-18T12:50:27Z")
Where can I find the solutions of minitests 1, 2 and 3? --- ## [Where are the example minitest?](https://forum.solidstate.quantumtinkerer.tudelft.nl/t/where-are-the-example-minitest/3797)
**Author:** [@khilversum](https://forum.solidstate.quantumtinkerer.tudelft.nl/u/khilversum)\ **Replies:** 2\ **Last updated:** [May 1, 2026, 8:38am UTC](https://forum.solidstate.quantumtinkerer.tudelft.nl/t/where-are-the-example-minitest/3797 "2026-05-01T08:38:49Z")
Hey I have a question. During the whole course in this forum I haven’t had any sight of example minitest or example exams. While in a question I saw that someone does have acces to them leading to the conclusion that my … --- ## [Typo in Semiconductors/Basic Principles/Conduction section](https://forum.solidstate.quantumtinkerer.tudelft.nl/t/typo-in-semiconductors-basic-principles-conduction-section/3678)
**Author:** [@CGutierrez](https://forum.solidstate.quantumtinkerer.tudelft.nl/u/CGutierrez)\ **Replies:** 1\ **Last updated:** [December 2, 2025, 3:00pm UTC](https://forum.solidstate.quantumtinkerer.tudelft.nl/t/typo-in-semiconductors-basic-principles-conduction-section/3678 "2025-12-02T15:00:06Z")
Dear site organizers, Firstly, thank you for this site as I regularly use it in my Solid State Physics course. I came across a typographical error in the Semiconductors/Basic Principles/Conduction section in the senten… --- ## [Proposal to add to the book: a (more expansive) Index](https://forum.solidstate.quantumtinkerer.tudelft.nl/t/proposal-to-add-to-the-book-a-more-expansive-index/3552)
**Author:** [@vzinschitz](https://forum.solidstate.quantumtinkerer.tudelft.nl/u/vzinschitz)\ **Replies:** 0\ **Last updated:** [May 19, 2025, 12:46pm UTC](https://forum.solidstate.quantumtinkerer.tudelft.nl/t/proposal-to-add-to-the-book-a-more-expansive-index/3552 "2025-05-19T12:46:31Z")
Just a disclaimer: This is more of an idea that would make it a bit easier (possibly?) to navigate the site, but is also not necessary and really just a “if you find yourself with some free time on your hands” kind of si… --- ## [Solutions to extra exercises](https://forum.solidstate.quantumtinkerer.tudelft.nl/t/solutions-to-extra-exercises/3514)
**Author:** [@FlorisvanderWerff](https://forum.solidstate.quantumtinkerer.tudelft.nl/u/FlorisvanderWerff)\ **Replies:** 2\ **Last updated:** [May 18, 2025, 12:26pm UTC](https://forum.solidstate.quantumtinkerer.tudelft.nl/t/solutions-to-extra-exercises/3514 "2025-05-18T12:26:34Z")
Dear @anton-akhmerov, @t.vandersar Would it be possible to make the solutions to the extra excercies found in the attic section available? --- ## [Incorrect math display in "Band structures in 2D" Question 3 solutions](https://forum.solidstate.quantumtinkerer.tudelft.nl/t/incorrect-math-display-in-band-structures-in-2d-question-3-solutions/3504)
**Author:** [@vzinschitz](https://forum.solidstate.quantumtinkerer.tudelft.nl/u/vzinschitz)\ **Replies:** 3\ **Last updated:** [May 8, 2025, 1:16pm UTC](https://forum.solidstate.quantumtinkerer.tudelft.nl/t/incorrect-math-display-in-band-structures-in-2d-question-3-solutions/3504 "2025-05-08T13:16:23Z")
There seems to be an issue with the math display in question 3 solutions of Band structures in 2D (Band structures in 2D - Open Solid State Notes). I reloaded the page multiple time but the problem persists, so I believ… --- ## [Solutions](https://forum.solidstate.quantumtinkerer.tudelft.nl/t/solutions/3435)
**Author:** [@Victor](https://forum.solidstate.quantumtinkerer.tudelft.nl/u/Victor)\ **Replies:** 3\ **Last updated:** [May 6, 2025, 5:57pm UTC](https://forum.solidstate.quantumtinkerer.tudelft.nl/t/solutions/3435 "2025-05-06T17:57:18Z")
Dear @anton-akhmerov, @t.vandersar, Would it be possible to make the solutions to the exercises available sometime after the exercise class, but still within the same day? --- ## [Missing warmup answers in Doping and devices](https://forum.solidstate.quantumtinkerer.tudelft.nl/t/missing-warmup-answers-in-doping-and-devices/3068)
**Author:** [@koent](https://forum.solidstate.quantumtinkerer.tudelft.nl/u/koent)\ **Replies:** 0\ **Last updated:** [May 20, 2024, 6:25pm UTC](https://forum.solidstate.quantumtinkerer.tudelft.nl/t/missing-warmup-answers-in-doping-and-devices/3068 "2024-05-20T18:25:07Z")
As the title says, the warmup questions are missing from the answers page --- ## [Basic principles warmup 4, missing minus sign](https://forum.solidstate.quantumtinkerer.tudelft.nl/t/basic-principles-warmup-4-missing-minus-sign/3053)
**Author:** [@koent](https://forum.solidstate.quantumtinkerer.tudelft.nl/u/koent)\ **Replies:** 1\ **Last updated:** [May 20, 2024, 2:50pm UTC](https://forum.solidstate.quantumtinkerer.tudelft.nl/t/basic-principles-warmup-4-missing-minus-sign/3053 "2024-05-20T14:50:57Z")
It was already pointed out last year but here it should say -E\_F, or e^{(E\_f-E\_c)\\beta} --- ## [Incorrect answer numbering Basic principles exercise 2](https://forum.solidstate.quantumtinkerer.tudelft.nl/t/incorrect-answer-numbering-basic-principles-exercise-2/3055)
**Author:** [@koent](https://forum.solidstate.quantumtinkerer.tudelft.nl/u/koent)\ **Replies:** 0\ **Last updated:** [May 20, 2024, 8:09am UTC](https://forum.solidstate.quantumtinkerer.tudelft.nl/t/incorrect-answer-numbering-basic-principles-exercise-2/3055 "2024-05-20T08:09:05Z")
In this exercise the first subquestion is not labeled in the answers, so every subsequent answer is labeled incorrectly --- ## [Incorrect exercise numbering answers x-ray](https://forum.solidstate.quantumtinkerer.tudelft.nl/t/incorrect-exercise-numbering-answers-x-ray/3023)
**Author:** [@koent](https://forum.solidstate.quantumtinkerer.tudelft.nl/u/koent)\ **Replies:** 0\ **Last updated:** [May 15, 2024, 8:00am UTC](https://forum.solidstate.quantumtinkerer.tudelft.nl/t/incorrect-exercise-numbering-answers-x-ray/3023 "2024-05-15T08:00:43Z")
In the answers of X-ray diffraction exercise 1 is written as exercise 2 --- ## [Incorrect question numbering crystal structure exercise 1](https://forum.solidstate.quantumtinkerer.tudelft.nl/t/incorrect-question-numbering-crystal-structure-exercise-1/3010)
**Author:** [@koent](https://forum.solidstate.quantumtinkerer.tudelft.nl/u/koent)\ **Replies:** 0\ **Last updated:** [May 14, 2024, 7:49am UTC](https://forum.solidstate.quantumtinkerer.tudelft.nl/t/incorrect-question-numbering-crystal-structure-exercise-1/3010 "2024-05-14T07:49:40Z")
Question 1.5 is corresponds to 1.5 and 1.6 in the answers --- ## [Solutions to warm-up exercises in lecture 14 are missing entirely](https://forum.solidstate.quantumtinkerer.tudelft.nl/t/solutions-to-warm-up-exercises-in-lecture-14-are-missing-entirely/3003)
**Author:** [@eamaldi](https://forum.solidstate.quantumtinkerer.tudelft.nl/u/eamaldi)\ **Replies:** 0\ **Last updated:** [May 13, 2024, 9:41am UTC](https://forum.solidstate.quantumtinkerer.tudelft.nl/t/solutions-to-warm-up-exercises-in-lecture-14-are-missing-entirely/3003 "2024-05-13T09:41:13Z")
Solutions to warm-uSolutions to warm-up exercises in lecture 14 are missing entirely --- ## [Typo in solution of warm up 3, many atoms](https://forum.solidstate.quantumtinkerer.tudelft.nl/t/typo-in-solution-of-warm-up-3-many-atoms/2997)
**Author:** [@koent](https://forum.solidstate.quantumtinkerer.tudelft.nl/u/koent)\ **Replies:** 1\ **Last updated:** [May 12, 2024, 9:43pm UTC](https://forum.solidstate.quantumtinkerer.tudelft.nl/t/typo-in-solution-of-warm-up-3-many-atoms/2997 "2024-05-12T21:43:41Z")
“The Schroedinger equation yields” :heart\_eyes: --- ## [Latex equation does not display](https://forum.solidstate.quantumtinkerer.tudelft.nl/t/latex-equation-does-not-display/2925)
**Author:** [@koent](https://forum.solidstate.quantumtinkerer.tudelft.nl/u/koent)\ **Replies:** 2\ **Last updated:** [May 2, 2024, 12:29pm UTC](https://forum.solidstate.quantumtinkerer.tudelft.nl/t/latex-equation-does-not-display/2925 "2024-05-02T12:29:26Z")
in the solutions of band structures in 2d the latex equation does not diplay --- ## [Missing newline in NFEM exercise 2.3-2.4](https://forum.solidstate.quantumtinkerer.tudelft.nl/t/missing-newline-in-nfem-exercise-2-3-2-4/2946)
**Author:** [@koent](https://forum.solidstate.quantumtinkerer.tudelft.nl/u/koent)\ **Replies:** 0\ **Last updated:** [April 29, 2024, 10:09am UTC](https://forum.solidstate.quantumtinkerer.tudelft.nl/t/missing-newline-in-nfem-exercise-2-3-2-4/2946 "2024-04-29T10:09:33Z")
It is a bit unclear where question 2.3 stops, I think there is supposed to be a newline here? --- ## [Solutions many atoms for unit cell](https://forum.solidstate.quantumtinkerer.tudelft.nl/t/solutions-many-atoms-for-unit-cell/2891)
**Author:** [@Nadia](https://forum.solidstate.quantumtinkerer.tudelft.nl/u/Nadia)\ **Replies:** 2\ **Last updated:** [April 13, 2024, 8:44am UTC](https://forum.solidstate.quantumtinkerer.tudelft.nl/t/solutions-many-atoms-for-unit-cell/2891 "2024-04-13T08:44:34Z")
Is it possible to post the solutions of many atoms for unit cell? --- ## [Wrong negative sign in Tight binding model under Density of States](https://forum.solidstate.quantumtinkerer.tudelft.nl/t/wrong-negative-sign-in-tight-binding-model-under-density-of-states/2848)
**Author:** [@fsfetcu](https://forum.solidstate.quantumtinkerer.tudelft.nl/u/fsfetcu)\ **Replies:** 1\ **Last updated:** [April 12, 2024, 3:18am UTC](https://forum.solidstate.quantumtinkerer.tudelft.nl/t/wrong-negative-sign-in-tight-binding-model-under-density-of-states/2848 "2024-04-12T03:18:53Z")
Hi, Should the argument of the arccos not be (E\_0-E)/2t? Or am I missing something? --- ## [Small typo in Drude model](https://forum.solidstate.quantumtinkerer.tudelft.nl/t/small-typo-in-drude-model/2832)
**Author:** [@mjsikkema](https://forum.solidstate.quantumtinkerer.tudelft.nl/u/mjsikkema)\ **Replies:** 1\ **Last updated:** [April 4, 2024, 6:07pm UTC](https://forum.solidstate.quantumtinkerer.tudelft.nl/t/small-typo-in-drude-model/2832 "2024-04-04T18:07:17Z")
In the equation where the average velocity is calculated, t is written as a vector once. --- ## [Solutions to exercises of Debye model](https://forum.solidstate.quantumtinkerer.tudelft.nl/t/solutions-to-exercises-of-debye-model/2831)
**Author:** [@mjsikkema](https://forum.solidstate.quantumtinkerer.tudelft.nl/u/mjsikkema)\ **Replies:** 0\ **Last updated:** [April 4, 2024, 3:12pm UTC](https://forum.solidstate.quantumtinkerer.tudelft.nl/t/solutions-to-exercises-of-debye-model/2831 "2024-04-04T15:12:03Z")
In the first line of the solution of exercise 2.1, I think there is a factor g(\\omega) missing. Also, the integral has limits, but the integration variable is a vector, so that does not make sense. I also think that in … --- ## [Missing part of equation in "X-Ray Diffraction" course notes](https://forum.solidstate.quantumtinkerer.tudelft.nl/t/missing-part-of-equation-in-x-ray-diffraction-course-notes/2452)
**Author:** [@rhjatol](https://forum.solidstate.quantumtinkerer.tudelft.nl/u/rhjatol)\ **Replies:** 1\ **Last updated:** [May 4, 2023, 12:34pm UTC](https://forum.solidstate.quantumtinkerer.tudelft.nl/t/missing-part-of-equation-in-x-ray-diffraction-course-notes/2452 "2023-05-04T12:34:34Z")
Hello! In the “X-Ray Diffraction” course notes, at the “The reciprocal lattice as a Fourier transform” section, we arrive at the sum \\sum\_\\mathbf{G} = \\delta (\\mathbf{k} - \\mathbf{G}). Following the same derivation in t… --- ## [Missing $\\beta$ in equation Debye model](https://forum.solidstate.quantumtinkerer.tudelft.nl/t/missing-beta-in-equation-debye-model/2400)
**Author:** [@rhjatol](https://forum.solidstate.quantumtinkerer.tudelft.nl/u/rhjatol)\ **Replies:** 1\ **Last updated:** [April 5, 2023, 12:01pm UTC](https://forum.solidstate.quantumtinkerer.tudelft.nl/t/missing-beta-in-equation-debye-model/2400 "2023-04-05T12:01:56Z")
Hi! In the Debye model lecture notes, the equation for the expectation of energy (total energy) is given, just below the equation for the dispersion relation. In the equation, however, the n\_B (\\hbar \\omega) -term should… --- ## [Google shows links to an old version of the lecture notes](https://forum.solidstate.quantumtinkerer.tudelft.nl/t/google-shows-links-to-an-old-version-of-the-lecture-notes/1947)
**Author:** [@Maciej](https://forum.solidstate.quantumtinkerer.tudelft.nl/u/Maciej)\ **Replies:** 2\ **Last updated:** [May 18, 2022, 7:47am UTC](https://forum.solidstate.quantumtinkerer.tudelft.nl/t/google-shows-links-to-an-old-version-of-the-lecture-notes/1947 "2022-05-18T07:47:38Z")
@anton-akhmerov : Links to the lecture notes often come in the top of google search results for some solid state physics related concepts :partying\_face: , but some of them link to what looks like a proto-version of the … --- ## [Basic principles: momenta signs for deriving conductivity](https://forum.solidstate.quantumtinkerer.tudelft.nl/t/basic-principles-momenta-signs-for-deriving-conductivity/1888)
**Author:** [@Roland](https://forum.solidstate.quantumtinkerer.tudelft.nl/u/Roland)\ **Replies:** 0\ **Last updated:** [April 11, 2022, 12:00pm UTC](https://forum.solidstate.quantumtinkerer.tudelft.nl/t/basic-principles-momenta-signs-for-deriving-conductivity/1888 "2022-04-11T12:00:51Z")
In Semiconductors \> Basic Principles \> Conduction the following expressions are given: - m\_e v\_e/\\tau\_e = -eE and - m\_h v\_h/\\tau\_h = eE . I think these should be: m\_e v\_e/\\tau\_e = -eE and m\_h v\_h/\\tau\_h = eE (which … --- ## [Attic - final exam](https://forum.solidstate.quantumtinkerer.tudelft.nl/t/attic-final-exam/1816)
**Author:** [@VDumaij](https://forum.solidstate.quantumtinkerer.tudelft.nl/u/VDumaij)\ **Replies:** 3\ **Last updated:** [April 5, 2022, 11:10am UTC](https://forum.solidstate.quantumtinkerer.tudelft.nl/t/attic-final-exam/1816 "2022-04-05T11:10:09Z")
Hi, Are the documents in the attic section part of the exam? Kind regards, Vincent --- ## [Mistake answer model lecture 14 Exercise 4.4](https://forum.solidstate.quantumtinkerer.tudelft.nl/t/mistake-answer-model-lecture-14-exercise-4-4/1814)
**Author:** [@rmwesterveld](https://forum.solidstate.quantumtinkerer.tudelft.nl/u/rmwesterveld)\ **Replies:** 1\ **Last updated:** [March 31, 2022, 11:43am UTC](https://forum.solidstate.quantumtinkerer.tudelft.nl/t/mistake-answer-model-lecture-14-exercise-4-4/1814 "2022-03-31T11:43:22Z")
Hi, I think I found another mistake, namely with the density of states for both electrons and holes. I think a for factor \\frac{L\_x L\_y}{(2 \\pi)^2} is missing since this always comes in front of the density iof states. --- ## [Mistake lecture notes Lecture 14](https://forum.solidstate.quantumtinkerer.tudelft.nl/t/mistake-lecture-notes-lecture-14/1813)
**Author:** [@rmwesterveld](https://forum.solidstate.quantumtinkerer.tudelft.nl/u/rmwesterveld)\ **Replies:** 1\ **Last updated:** [March 30, 2022, 8:11pm UTC](https://forum.solidstate.quantumtinkerer.tudelft.nl/t/mistake-lecture-notes-lecture-14/1813 "2022-03-30T20:11:27Z")
Hi I think there is a mistake made for the fermi energy in the excentric regime for N\_A\>N\_D. Namely if we found that n\_h \\approx N\_A-N\_D and that n\_h \\approx N\_v e^{\\frac{E\_v-E\_f}{k\_bT}} this would result to E\_f = E\_v+k\_… --- ## [kT in basic principles on semiconductors](https://forum.solidstate.quantumtinkerer.tudelft.nl/t/kt-in-basic-principles-on-semiconductors/1807)
**Author:** [@pvanandel](https://forum.solidstate.quantumtinkerer.tudelft.nl/u/pvanandel)\ **Replies:** 1\ **Last updated:** [March 29, 2022, 3:03pm UTC](https://forum.solidstate.quantumtinkerer.tudelft.nl/t/kt-in-basic-principles-on-semiconductors/1807 "2022-03-29T15:03:54Z")
Many times in basic priciples k\_BT is written as kT. A bit confusing. Maybe write ß instead? [Next page](https://forum.solidstate.quantumtinkerer.tudelft.nl/c/site-feedback/2.md?page=1)