Full color display
View Patent ↗A full color display comprising a red, a green, and a blue light emitting diode, each light emitting diode including a light emitting region having at least one layer of single crystal rare earth material, the rare earth material in each of the light emitting diodes having at least one radiative transition, and the rare earth material producing a radiation wavelength of approximately 640 nm in the red light emitting diode, 540 nm in the green light emitting diode, and 460 nm in the blue light emitting diode. Generally, the color of each LED is determined by selecting a rare earth with a radiative transition producing a radiation wavelength at the selected color. In cases where the rare earth has more than one radiative transition, tuned mirrors can be used to select the desired color.
1. A method of fabricating a full color display comprising the steps of:
providing a substrate;
defining a plurality of regularly positioned pixels on the substrate, each pixel including a red, a green, and a blue light emitting diode;
selecting a rare earth material for each of the red, the green, and the blue light emitting diodes, the rare earth materials having at least one radiative transition producing a radiation wavelength of approximately 640 nm for the red light emitting diode, 540 nm for the green light emitting diode, and 460 nm for the blue light emitting diode, respectively;
positioning a first mirror on the substrate for each light emitting diode in each pixel;
epitaxially growing a first cladding layer of intrinsic single crystal semiconductor material on each of the first mirrors;
epitaxially growing a light emitting area including at least one thin single crystal layer of the selected rare earth material on the first cladding layer of each light emitting diode of each pixel;
epitaxially growing a second cladding layer of intrinsic single crystal semiconductor material on the light emitting area of each light emitting diode of each pixel; and
positioning a second mirror on the second cladding layer of each light emitting diode of each pixel.
2. A method as claimed in claim 1 wherein the first mirror of each light emitting diode of each pixel is a first mirror stack including a plurality of mirror pairs, and each mirror pair has an effective thickness of at least one half wavelength at the emitted color.
3. A method as claimed in claim 1 wherein the step of selecting the rare earth material for the red light emitting diode includes selecting Erbium (Er), selecting the rare earth for the green light emitting diode includes selecting Erbium (Er), and selecting the rare earth material for the blue light emitting diode includes selecting Thulium (Tm).
4. A method as claimed in claim 3 wherein the step of positioning the first mirror in each of the red light emitting diode and the green light emitting diode includes a step of epitaxially growing a plurality of mirror pairs, and growing each mirror pair with an effective thickness of at least one half wavelength at the radiation wavelength of the emitted color.
5. A method as claimed in claim 3 wherein the step of selecting the rare earth material for the blue light emitting diode includes selecting Thulium (Tm).