Method for making a light emitting diode having a P-N junction doped with one or more luminescent activator ions
View Patent ↗A light emitting diode (LED) includes a p-n junction containing luminescent activator ions. The visible emission from the activator ions preferably complementing the band edge emission of the LED in order to produce an overall white emission from the LED. In a preferred embodiment, the LED has double heterojunction structure having a semiconductor active layer between two confinement layers. The semiconductor active layer includes activator ions preferably selected from among Eu 3+ , Tb 3+ , Dy 3+ , Pr 3+ , Tm 3+ , and Mn 2+ . The electron-hole pairs trapped within the active layer sensitize the activator ions, causing the activator ions to emit light.
1. A method for making a light emitting diode having a P-N junction doped with a luminescent activator ion, comprising the steps of:
(a) observing an excitation spectrum of the luminescent activator ion in a wide-gap, nitride-based semiconductor material;
(b) formulating a semiconductor composition to have a band edge emission that overlaps a selected excitation peak of the luminescent activator ion, the semiconductor composition being selected from AlN, GaN, InN and alloys thereof; and
(c) doping the semiconductor composition with the luminescent activator ion to form the P-N junction of the light emitting diode.
2. The method of claim 1 wherein the wide-gap, nitride-based semiconductor material is GaN.
3. The method of claim 2 wherein the luminescent activator ion is selected from the group of ions consisting of Eu 3+ , Tb 3+ , Dy 3+ , Pr 3+ , Tm 3+ , and Mn 2+ .
4. The method of claim 1 wherein the luminescent activator ion is selected from the group of ions consisting of Eu 3+ , Tb 3+ , Dy 3+ , Pr 3+ , Tm 3+ , and Mn 2+ .
5. The method of claim 1 wherein the P-N junction is doped with more than one luminescent activator ion.