Light emitting diode

A light emitting diode of silicon carbide having a p-n junction, comprising:

• an n-type layer of silicon carbide doped with donor impurities;
• a first p-type layer of silicon carbide formed on the n-type layer, said first p-type layer being doped with acceptor impurities and donor impurities;
• and
• a second p-type layer of silicon carbide formed on the first p-type layer, said second p-type layer being doped with acceptor impurities;
• wherein said first p-type layer has a thickness less than the diffusion length of electrons having flowed from said n-type layer under a forward bias condition, so that said first p-type layer effects light emission by donor-acceptor pairs caused by recombination with the electrons having flowed from said n-type layer, and said second p-type layer effects light emission related to the acceptor impurities caused by recombination with the electrons having flowed from said n-type layer.

A light emitting diode, comprising:

• an n-type layer of silicon carbide doped with donor impurities;
• a first p-type layer of silicon carbide formed on the n-type layer;
• and
• a second p-type layer of silicon carbide formed on the first p-type layer, wherein one of said first and second p-type layers is doped with acceptor impurities, and the other of said first and second p-type layers is doped with acceptor impurities and donor impurities;
• wherein an application of a forward bias voltage across a p-n junction formed by said n-type layer and said first and second p-type layers produces emission of light which is substantially blue monochromatic;
• and
• wherein the first p-type layer has a thickness which is less than the diffusion length of electrons flowing from the n-type under s forward bias condition.

A light emitting diode according to, comprising:

• an n-type semiconductor layer doped with donor impurities;
• a first p-type semiconductor layer formed on the n-type semiconductor layer;
• and
• a second p-type semiconductor layer formed on the first p-type semiconductor layer, wherein one of said first and second p-type semiconductor layers is doped with acceptor impurities, and the other of said first and second p-type semiconductor layers is doped with acceptor impurities and donor impurities;
• wherein an application of a forward bias voltage across a p-n junction formed by said n-type semiconductor layer and said first and second p-type semiconductor layers produces emission of light which is substantially blue monochromatic;
• and
• wherein the first p-type semiconductor layer has a thickness which is less than the diffusion length of electrons flowing from the n-type semiconductor layer under a forward bias condition.