Micro-light emitting diode (micro-LED) device
A micro-light emitting diode (micro-LED) device includes a receiving substrate and a micro-LED. The micro-LED includes a first type semiconductor layer, a second type semiconductor layer, a current controlling layer, at least one reflective layer, and at least one first electrode. The second type semiconductor layer is joined with the first type semiconductor layer. The current controlling layer is joined with one of the first type semiconductor layer and the second type semiconductor layer, the current controlling layer having at least one opening therein. The reflective layer electrically is coupled with the first type semiconductor layer. The first electrode is disposed on a surface of the reflective layer facing the receiving substrate. The first electrode forms an adhesive bonding system with the receiving substrate.
1. A micro-light emitting diode device, comprising:
a receiving substrate; and
a micro-LED comprising:
a first type semiconductor layer;
a second type semiconductor layer joined with the first type semiconductor layer;
a current controlling layer joined with the first type semiconductor layer, the current controlling layer having at least one opening therein;
at least one reflective layer electrically coupled with the first type semiconductor layer, wherein a portion of the reflective layer is present within said at least one opening of the current controlling layer and in surface-to-surface contact with an inner side surface of the current controlling layer, and a surface of the reflective layer away from the current controlling layer is substantially flat;
at least one first electrode disposed between the reflective layer and the receiving substrate, wherein the first electrode forms an adhesive bonding system with the receiving substrate;
a second electrode electrically connected with the second type semiconductor layer; and
an ohmic contact layer disposed between and joined with the second electrode and the second type semiconductor layer, wherein a vertical projection of said portion of the reflective layer on the receiving substrate is overlapped with a vertical projection of the ohmic contact layer on the receiving substrate.
2. The micro-LED device of claim 1 , wherein a bonding temperature of the adhesive bonding system is lower than a melting point of the reflective layer.
3. The micro-LED device of claim 1 , wherein the receiving substrate comprises a bonding electrode, and the bonding electrode and the first electrode form the adhesive bonding system.
4. The micro-LED device of claim 3 , wherein the adhesive bonding system is a eutectic system, a soldering contact, a transient liquid phase sintering system, or a conductive adhesive bonding system formed by the bonding electrode and the first electrode, and a bonding temperature of the adhesive bonding system is a eutectic point of the eutectic system, a soldering point of the soldering contact, a sintering point of the transient liquid phase sintering system, or a conductive adhesive bonding temperature of the conductive adhesive bonding system.
5. The micro-LED device of claim 3 , wherein the first type semiconductor layer is electrically coupled with the first electrode through the opening of the current controlling layer, and a contact area between the first electrode and the bonding electrode is greater than a size of the opening.
6. The micro-LED device of claim 3 , wherein the bonding electrode is a metal layer, a transparent conductive layer, or a conductive adhesive layer.
7. The micro-LED device of claim 1 , wherein the first electrode is a metal layer or a conductive adhesive layer.
8. The micro-LED device of claim 1 , wherein a plurality of the reflective layers are stacked together.
9. The micro-LED device of claim 1 , wherein a plurality of the first electrodes are stacked together.
10. The micro-LED device of claim 1 , wherein the current controlling layer is a dielectric layer.
11. The micro-LED device of claim 1 , wherein said one of the first type semiconductor layer and the second type semiconductor layer has a resistivity ρ s and a thickness t s , the other of the first type semiconductor layer and the second type semiconductor layer has a resistivity ρ o and a thickness t o , and
t
s
ρ
s
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t
o
ρ
o
.
12. The micro-LED device of claim 1 , wherein the reflective layer is made of metal.
13. The micro-LED device of claim 1 , wherein the micro-LED comprises:
an active layer disposed between the first type semiconductor layer and the second type semiconductor layer.
14. The micro-LED device of claim 13 , further comprising:
an additional current controlling layer disposed in the second type semiconductor layer and in contact with the active layer, and the additional current controlling layer having at least one opening therein.
15. The micro-LED device of claim 13 , further comprising:
an additional current controlling layer disposed in the second type semiconductor layer without contacting the active layer, and the additional current controlling layer having at least one opening therein.
16. The micro-LED device of claim 1 , wherein the micro-LED comprises:
an additional current controlling layer joined with the second type semiconductor layer and having at least one opening therein.
17. The micro-LED device of claim 1 , wherein the micro-LED comprises an additional ohmic contact layer disposed between the first type semiconductor layer and the reflective layer.