what is the difference between reverse, dark and leakage current of a (photo-)diode? From my current understanding it all seems to be the same?

  • $\begingroup$ A quick google gets you a page on dark current which answers your question. What research did you do before asking the question here? $\endgroup$ – Lio Elbammalf Jun 14 '18 at 11:35
  • $\begingroup$ Yes, I did. A lot, that's why I probably can reduce the problem of having several terms to describe very similar things. What did you do to help solving this issue? $\endgroup$ – Ben Jun 14 '18 at 11:45
  • $\begingroup$ The wikipedia page on dark current includes the information in your accepted answer, just in different words. I'm just unsure as to why you had to ask someone on here for it, rather than read the wiki page yourself. $\endgroup$ – Lio Elbammalf Jun 14 '18 at 13:43
  • $\begingroup$ When you already know it, the wikipedia site provides all information but it doesn't really highlight the difference. Hence, it could be but to be sure you have to ask someone. At least this is how I proceed, I'm seeking for explicit information. $\endgroup$ – Ben Jun 15 '18 at 6:47

What's common for all these currents is that they are reverse, i.e., they flow when a reverse voltage is applied to a diode, but there are some differences.

A dark reverse current in a photodiode flows when there is no light and is, naturally, different (smaller) than the reverse current in a photodiode exposed to light.

Although some regular diodes could have some sensitivity to light, the term "dark current" is not used to describe their reverse current, since it would not be much different from a "non-dark" reverse current. Instead, we use the term "reverse leakage current".

With that said, reverse dark current and reverse leakage current have similar underlying mechanisms. They both increase with the temperature and the reverse voltage and, in most cases, are both considered undesirable.

  • $\begingroup$ Thank you! The reverse current includes the dark reverse current, right? $\endgroup$ – Ben Jun 14 '18 at 11:43
  • $\begingroup$ Dark current is defined as a reverse current of photoelectric devices (including photodiodes), when there is no illumination. So, yes, it is a (kind of) a reverse current defined for specific class of devices (photoelectric devices) under specific conditions (no light plus some specific voltage and temperature). $\endgroup$ – V.F. Jun 14 '18 at 12:38

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