Monolithic multicolor direct view display containing different color LEDs and method of making thereof
A direct view multicolor light emitting device includes blue, green and red light emitting diodes (LEDs) in each pixel. The different light emitting diodes can be formed by depositing different types of active region layers in a stack such that deposition area of each subsequent active region is less than the deposition area of any preceding active region, and by patterning the active region layers into different types of stacks. The active region layers may be formed as planar layers, or may be formed on semiconductor nanowires. The active region layers can emit light at the respective target wavelength range. Alternatively, at least one of green and red phosphor materials, dye materials, or quantum dots may be used instead of or in addition to the active regions that emit light at a wavelength different from a target wavelength of a respective LED.
1. A light emitting device, comprising:
a plurality of blue, green and red light emitting diodes (LEDs), wherein each of the plurality of blue, green and red LEDs comprises at least one semiconductor region of a first conductivity type and at least one semiconductor region of a second conductivity type;
wherein:
the blue LEDs further comprise a blue active region located between the least one semiconductor region of the first conductivity type and at least one semiconductor region of the second conductivity type;
the green LEDs further comprise the blue active region and a green active region located between the least one semiconductor region of the first conductivity type and at least one semiconductor region of the second conductivity type; and
the red LEDs further comprise the blue active region, a green active region and a red active region located between the least one semiconductor region of the first conductivity type and at least one semiconductor region of the second conductivity type.
2. The device of claim 1 , wherein:
the green active region and the red active region each have a thickness of 1 to 100 nm; and
the device comprises a direct view multicolor light emitting device that contains the blue LED, the green LED and the red LEDs in each pixel.
3. The device of claim 1 , wherein:
the at least one semiconductor region of the first conductivity type comprises a plurality of semiconductor nanowires of the first conductivity type;
the blue, green and red active regions comprise shells located over the plurality of semiconductor nanowires; and
the at least one semiconductor region of the second conductivity type comprises outer shells of the second conductivity type located around the blue, green and red active regions and the plurality of semiconductor nanowires.
4. The device of claim 1 , wherein:
the at least one semiconductor region of the first conductivity type comprises a planar semiconductor layer of the first conductivity type;
the blue, green and red active regions comprise layers located over the planar semiconductor layer of the first conductivity type; and
the at least one semiconductor region of the second conductivity type comprises a at least one planar semiconductor layer of the second conductivity type located over the layers which comprise the blue, green and red active regions.
5. A light emitting device, comprising:
a first light emitting diode including a first stack containing a first-type active region, and configured to emit light at a first peak wavelength;
a second light emitting diode including a second stack including the first-type active region and a second-type active region having a different composition than the first-type active region, and configured to emit light at a second wavelength that is different from the first wavelength; and
a third light emitting diode including a third stack containing the first-type active region, the second-type active region and a third-type active region having a different composition from the first and second-type active regions, and configured to emit light at a third wavelength that is different from the first and second wavelengths.