Crystalline color-conversion device
According to an embodiment, a crystalline color-conversion device includes an electrically driven first light emitter, for example a blue or ultraviolet LED, for emitting light having a first energy in response to an electrical signal. An inorganic solid single-crystal direct-bandgap second light emitter having a bandgap of a second energy less than the first energy is provided in association with the first light emitter. The second light emitter is electrically isolated from, located in optical association with, and physically connected to the first light emitter so that in response to the electrical signal the first light emitter emits first light that is absorbed by the second light emitter and the second light emitter emits second light having a lower energy than the first energy.
1. A method of making a crystalline color-conversion device, comprising:
providing an electrically driven first light emitter for emitting first light having a first energy in response to an electrical current signal, wherein the electrically driven first light emitter is electrically connected to two or more electrical contacts that provide the electrical current signal to the first light emitter;
providing an optically driven inorganic solid single-crystal direct-bandgap second light emitter having a bandgap of a second energy less than the first energy; and
micro transfer printing the second light emitter from a source substrate onto the first light emitter or micro transfer printing the first light emitter from a source substrate onto the second light emitter so that the second light emitter (i) is electrically isolated from the first light emitter so that current passing through the first light emitter does not pass through the second light emitter, (ii) is located in optical association with the first light emitter, and (iii) is located within 0 to 250 microns of the first light emitter such that in response to the electrical signal the first light emitter emits first light that is absorbed by the second light emitter and the second light emitter emits second light having a lower energy than the first energy.
2. The method of claim 1 , wherein the first light emitter and the second light emitter form a light-emitting conversion structure and the method comprises micro-transfer printing the light-emitting conversion structure from a source substrate onto a display substrate.
3. The method of claim 1 , comprising forming an inorganic solid single-crystal direct-bandgap layer on a source substrate and disposing the first light emitter onto the inorganic solid single-crystal direct-bandgap layer.
4. The method of claim 3 , comprising etching the layer to form a plurality of spatially separated crystalline color-conversion devices on the source substrate.
5. The method of claim 4 , comprising micro transfer printing the crystalline color-conversion devices from the source substrate to a display substrate.
6. The method of claim 1 , comprising providing an inorganic solid single-crystal direct-bandgap source substrate and disposing the first light emitters onto the source substrate.
7. The method of claim 6 , comprising etching the source substrate to form a plurality of spatially separated crystalline color-conversion devices.
8. The method of claim 7 , comprising micro transfer printing the plurality of crystalline color-conversion devices from the source substrate to a display substrate.