Instructables

can I make a home made LED?

I don´t know if the resins used to make leds are special trated, or very difficult to find the metal of "filaments". But my question is: Is possible to make a home made LED?

Plasmana5 years ago
I know all semiconductors give off very little light when they are in operation, if you successfully break the plastic packaging without breaking the semiconductor, go in a dark room, and you might be able to see some light... LED's are really diodes, they are just specially design to give off far more light than regular diodes. It is much better to buy LED's instead.
eric m4 years ago
 google  homemade oled. 
jbowmas4 years ago
If you are simply interested in generating the LED effect at home, then yes, you can. You are not going to be able to match (within several orders of magnitude) the cost and quality of a commercial LED, though. Try googling "homemade LED Silicon Carbide". There are several sites and videos on the topic.

First though, you should understand what is going on. A diode consists of either two differently doped semiconductors in contact, or a metal in contact with a semiconductor. The Silicon Carbide LED is of the second type (called a Schottky Diode).

The basic premise of a diode is that one material is 'N' type, and the other is 'P' type. These designations refer to the the presence of electrons (N) or holes (P). Note that this does NOT mean that the N-type is negatively charged, or that the P type is positively charged. This is referring to the crystal structure: an N type crystal excludes electrons, pushing them into the conduction band. A P type crystal is the opposite... it has extra places where electrons can rest in the crystal.

When these two types are in contact, some of the electrons from the N-type will spill over into the P-type, up until the point where the electric charge they set up stops any further migration (a negative charge builds up on the P-type due to the electrons migrating there, and the opposite happens on the N-type). This explains the diode action: if you hook up a battery with the + to the N type and the - to the P type, the negative charge on the P-type will push back against the applied -, and the positive charge on the N-type will push back against the applied +.

Now back to the electrons and holes. There is an energy gap (referred to as the bandgap) between the conduction band and the electron holes in the crystal structure. When an electron falls from the conduction band into the hole, it gives up that amount of energy. This is called "electron-hole recombination", and is a very bad thing in silicon chips. The bandgap in silicon results in the energy being released as heat (called phonons).

However, in other materials, such as Gallium Arsenide, the bandgap energy is in the visible light area of the spectrum, and this electron-hole recombination results in photons of light being given off. That is the light from the Light Emitting Diode.

One last note: the "filiment" that you see in a commercial LED is simply a hookup wire. It is not actually a glowing filiment like a lightbulb has, nor is it part of the diode itself (as the wire is in the Silicon Carbide LED or any other Schottky Diode).
TLLCUK4 years ago
Unless you have a few million to play around with, some clever people  . . . just cheaper and easier in this case to buy them imho.
antiquekid34 years ago
Yes! You can! Get a chunk of silicon carbide and a small wire (cat's whisker) and touch it to the silicon carbide with current flowing in the correct direction, and you will have light! It was done in the 1920s! See: http://en.wikipedia.org/wiki/Led#Discoveries_and_early_devices
That would be really awesome if you could make some dirt cheap ones. Here, I just found out about blowing an LED up with a simple 9V and it would be fun if you had an endless supply of these and rig them up like a grenade... (hook up a timing button, activate it, and throw it somewhere... KABOOM! mwhahaha)... Hey! How about making an 'ible for that? :D
joinaqd5 years ago
no you cant make homemade leds....but i wish we could,that would be awesoem
benthekahn5 years ago
Theoretically, you could, but it would be much much cheaper and they would work better if you bought some.
UziMonkey5 years ago
No. It's not a light bulb with a filament, it's a semiconductor device. The semiconductor chip in there is a PN junction (just like normal diodes) with a finely tuned voltage requirement. Making a crude PN junction is not so hard. Tuning it to emit visible light is nearly impossible to do yourself.
short answer: NO! just go buy some LEDs they're really cheap!