Talk:Light-emitting diode physics

Add exact "bandgap" column to Materials table

"Voltage drop" is an imprecise value, because the voltage drop for a single LED is not exact but ranges depending on how much current (and hence much light you want to produce) and because the "knee" of any diode curve is smooth and not an exact voltage. However, the bandgap of the material in eV is an exact value. "Voltage drop" is still useful to think of when making circuits, so I'll leave that column for each color, but I was thinking of adding a bandgap value for each material. And I would probably also have the wavelenghs be for each specific material rather than a broad range. And I would sort the materials for each color in order of increasing bandgap (and decreasing wavelength). Em3rgent0rdr (talk) 16:52, 20 June 2024 (UTC)

I'm saying this because there is a distinction between bandgap and voltage drop. For instance, as an online libretext points out, "The band gap energy of an LED can be determined by measuring the voltage across an LED at the point which the LED barely begins to turn on." So voltage drop to provide significant illumination would be higher. Additionally, as a stackexchange answer says, there is also a small range of wavelenghts that are produced and some thermally-excited electrons may have high enough energy to jump the gap. I bring this up to emphasize that the bandgap is a key and precise property of each material and deserves its own column. Em3rgent0rdr (talk) 17:18, 20 June 2024 (UTC)

I-V plot of LEDs of various colors would be nice

An I-V plot of LEDs of various colors (from http://lednique.com/current-voltage-relationships/iv-curves/) would be nice, as seeing the curve helps understanding more than just giving a "voltage drop" range of particular LED color. If I can't find any a freely-licensed plot on the internet, then if I have time I could make some measurements with the LEDs and make a freely licensed plot. Em3rgent0rdr (talk) 19:16, 20 June 2024 (UTC)