Talk:Single-photon avalanche diode

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Noise statement[edit]

I believe this statement:

"Besides photon-generated carriers, also thermally-generated carriers (through generation-recombination processes within the semiconductor) can fire an avalanche process."

is mostly incorrect. Depleted silicon has relatively few thermally-generated carriers. Instead, the dominant sources of noise are tunneling-assisted and trap-assisted phenomenon (PhD thesis of Alex Rochas, EPFL).

Comment[edit]

Depleted silicon does have thermal generation by direct band to band thermal excitation (different from tunnelling). The dominant source of noise depends on the device - all three contribute to noise or dark counts. The sentence could be changed to:

"Besides photon-generated carriers, also thermally-generated carriers (through generation-recombination processes within the semiconductor), band-to-band tunnelling [citation to tunnelling], trap-assisted thermal generation, and trap-assisted tunnelling, can initiate an avalanche breakdown resulting in a dark count."

129.215.183.148 (talk) 08:19, 17 October 2011 (UTC)Eric Webster[reply]

Figure 2[edit]

Figure 2 appears to include an in-line resistor with the SPAD, otherwise the shape of the current would have an infinite slope, not a finite one. Should the caption be marked as such?

Answer: No, the SPAD series resistance is unavoidable in any real SPAD device. Typical series resistance is in the range of several hundreds of ohms. This resistance is due to the semiconductor neutral regions and to the metal contacts.

Un Explained Terms[edit]

There seems to be a few unexplained terms in this article - eg in the operating principle section Va and Vb are introduced - but there is no explaination of what they mean - they don't appear on the figure referenced either. — Preceding unsigned comment added by Wideofthemark (talk • contribs) 08:16, 10 April 2014 (UTC)[reply]

Unexplained/ poorly explained terms removed and replaced Carver1889 (talk) 14:28, 8 April 2022 (UTC)[reply]

InTechOpen as a source[edit]

Moved from User talk:Joel B. Lewis § Single-Photon Avalanche Diodes

– JBL (talk) 18:58, 9 May 2020 (UTC)[reply]

As a professional in the field, Fisher did indeed write a review covering 1900 to 1969 and this is of higher quality than Renker's overview. Previously this was cited but was removed despite the text being robustly researched, citing the historical literature extensively (120 references), being written by an author with a doctorate in the field and being in a book of other single-photon avalanche diode researchers, including the head of SPAD development at FBK. How should this be handled if wikipedia insists on removing DOI links to this historical review? — Preceding unsigned comment added by 150.143.115.238 (talk) 16:06, 9 May 2020 (UTC)[reply]

The same was as all other disputes on Wikipedia: via discussion and consensus-building (see WP:Consensus). The natural way to begin is to open a discussion on the article talk-page. It would also be a good idea to ping the relevant editors Headbomb and Ceyockey, who initially removed the citation, to invite them to discuss. --JBL (talk) 16:11, 9 May 2020 (UTC)[reply]

I don't understand the question. The only thing I can see there is the removal of citations published via InTech Open, a well-known vanity press. See WP:VANPRED#Use in the real world vs use on Wikipedia for more details on why we don't use those for sourcing. Headbomb {t · c · p · b} 16:16, 9 May 2020 (UTC)[reply]

I don't think the publisher's status particularly impacts the writing of a researcher that is independent of that publisher, especially if others in the field also choose that route. While it is true that higher impact journals publish better manuscripts, the quality of a manuscript is better characterized by the writing quality of the author and the robustness of their citation process. When combined with peer review independent of the publisher, we need to separate out the two quality concerns, a) the publisher and b) the author, and make an assessment of the correlation between those two. A blanket policy that doesn't make that assessment should be avoided. While vanity publishing is an issue, many mainstream publishers require an open access charge that is payable by the authors or their institution. IEEE, the predominant publisher for academic engineering, requires an author payable open access charge and Springer open access books also require this. Perhaps a happy medium can be arrived that that allows Wikipedia readers to see such citations, with a suitable footnote, so they can make their own opinions as to its robustness, but to also read that independent work if they wish. — Preceding unsigned comment added by 150.143.115.238 (talk) 17:24, 9 May 2020 (UTC)[reply]

I have removed the sentence with respect to the origins being 1890s 1900s as neither of the references, Renker or Cova extend back that far. — Preceding unsigned comment added by 150.143.115.238 (talk) 17:48, 9 May 2020 (UTC)[reply]

The issue isn't open access / pay-to-publish models, but rather pay-to-publish-without-legitimate-peer-review/publisher oversight. InTech is willing to publish hot garbage and is a massive spammer of unsolicited invitations to publish with them, so accordingly we threat everything they publish as hot garbage, unless a particular source is considered authoritative in the field (e.g. if there's a book review, from a known expert, published in a reputable venue, saying that a particular InTech book is actually worth something). Headbomb {t · c · p · b} 18:52, 9 May 2020 (UTC)[reply]

I have moved this discussion to the article's talk-page, which is where it really belongs. --JBL (talk) 18:58, 9 May 2020 (UTC)[reply]

Thanks for contacting me. This was done during a brief period (albeit involving over 1000 edits) when I was looking at the removal of citations to works from "predatory publishers". This was all about helping to reduce the incentive for the use of predatory publishers. Not everything that appears in a predatory publisher's work is unworthy of citation here, but as the essay Wikipedia:Vanity and predatory publishing states, "In the real world, it is possible that a work published in non-peer reviewed venue like a vanity press or a predatory journal represents excellent scholarship. ... On Wikipedia, we, unlike scholars, cannot assess individual published works. We must instead rely on the reputation of the venue in which something is published." There are, in fact, soft blocks on using some sources, as a script-added edit summary tag does get added when using sources on a to-avoid list - see https://en.wikipedia.org/wiki/Special:Tags, the tag name "Citing predatory open access journal". When I was conducting my removals, I would typically leave a 'citation needed' tag if I was removing the only citation for a passage, but simply removing the citation if it was one among several citations for a passage. --User:Ceyockey (talk to me) 10:00, 10 May 2020 (UTC)[reply]

Clarified that issue under discussion is the publisher.

As many Wikipedia pages link to non-citeable sources using the "Further Reading" section, would this be suitable? Other pages include a variety of sources in this way including commercial white papers, online simulations and news articles. — Preceding unsigned comment added by 146.199.116.32 (talk) 14:57, 13 May 2020 (UTC)[reply]

Article Rewrite[edit]

This article requires a full re-write. A proposal for its flow would be the following section structure: i) Overview, ii) Related Technologies and Sub-Types, iii) Application Areas, iv) Basic Operating Principles, v) Relevant Modern Research, vi) Commercialization Efforts, vii) Comparisons with APDs and viii) Historical Development and Early Pioneers}. — Preceding unsigned comment added by 150.143.115.238 (talk) 14:12, 10 May 2020 (UTC)[reply]

The section on their basic operating principles (iv) can be further split into the subsections of: a) Structure, b) Biasing Regions and he I-V Characteristic, c) Passive Detection Circuits, d) Active Detection Circuits, e) Photon counting and Saturation, f) Dark Count Rate, g) Afterpulsing Noise, h) Photon Timing and Jitter, and i) Optical Fill-Factor. — Preceding unsigned comment added by 150.143.115.238 (talk) 14:16, 10 May 2020 (UTC)[reply]

As part of the above suggested article structure, I have started this process and chosen selected sections to re-write. Others can contribute as needed to sections needing expansion. — Preceding unsigned comment added by EmdFish123 (talk • contribs) 20:27, 16 May 2020 (UTC)[reply]

A section on the photon detection efficiency (PDE) should be added with links to image sensor quantum efficiency (QE) etc and to modern concepts such as back-side illumination (BSI). — Preceding unsigned comment added by EmdFish123 (talk • contribs) 20:34, 16 May 2020 (UTC)[reply]

Section: "Comparisons with APDs" has now been updated with a) new text, b) references and c) links to related Wiki pages. (17/05/20: 08:50 UK) — Preceding unsigned comment added by EmdFish123 (talk • contribs) 07:53, 17 May 2020 (UTC)[reply]

Added section on "Biasing Regions and the I-V Characteristic", linking with wiki-pages on electric field etc. (17/05/20: 13:38 UK) — Preceding unsigned comment added by EmdFish123 (talk • contribs) 12:40, 17 May 2020 (UTC)[reply]

Added re-write of section "Optical Fill Factor", linking to other wiki-pages and adding references. This is edit 1 of 2 for this section. — Preceding unsigned comment added by EmdFish123 (talk • contribs) 15:30, 17 May 2020 (UTC)[reply]

Added re-write of section "Optical Fill Factor", edit 2 of 2 with more content on this topic. (17/05/20: 18:45 UK) — Preceding unsigned comment added by EmdFish123 (talk • contribs) 17:47, 17 May 2020 (UTC)[reply]

Updated section "Commercialisation Efforts", with some references to papers, but also external links section to company websites showing their activity in SPAD development or usage. (18/05/20: 12:01 UK) — Preceding unsigned comment added by EmdFish123 (talk • contribs) 11:04, 18 May 2020 (UTC)[reply]

Full re-write of introduction ("Overview"), better flow for non-technical readers, better linking to other wiki-pages. Included two review articles for CMOS and III-V SPADs. Moved some of the existing material into their dedicated sections to improve clarity. (18/05/20: 14:26 UK)

Commercial SPAD module figure[edit]

The figure showing the packaged component module from "Excelitas" has low informational value as to what SPADs are and do, and may misinform as SPADs come in different sizes, shapes and organizations (imaging arrays). With only one company's module the figure appears to me as a pretty distasteful example of hidden advertisement. Suggest to replace the headline figure with something that shows the working principle of typical SPADs. — Preceding unsigned comment added by 88.98.216.216 (talk) 11:47, 20 January 2022 (UTC)[reply]