Micro light-emitting device and display apparatus
A micro light-emitting device includes an epitaxial structure, a first type pad, a current commanding structure and an insulating layer. The epitaxial structure includes a first type semiconductor layer, a light-emitting layer and a second type semiconductor layer. The first type pad is disposed on the epitaxial structure and electrically connected to the first type semiconductor layer. The current commanding structure is disposed on the epitaxial structure and electrically connected to the second type semiconductor layer. An orthogonal projection area of the current commanding structure on the second type semiconductor layer is smaller than a surface area of a surface of the second type semiconductor layer. The insulating layer contacts a portion of the current commanding structure and a portion of the surface of the second type semiconductor layer. The insulating layer has an opening exposing at least a portion of the portion of the current commanding structure.
1. A micro light-emitting device, comprising:
an epitaxial structure, comprising:
a first type semiconductor layer;
a light-emitting layer disposed on the first type semiconductor layer; and
a second type semiconductor layer disposed on the light-emitting layer;
a first type pad disposed on the epitaxial structure and electrically connected to the first type semiconductor layer;
a current commanding structure disposed on the epitaxial structure and electrically connected to the second type semiconductor layer, wherein an orthogonal projection area of the current commanding structure on the second type semiconductor layer is smaller than a surface area of a surface of the second type semiconductor layer;
an insulating layer contacting a portion of the current commanding structure and a portion of the surface of the second type semiconductor layer, wherein the insulating layer has an opening exposing at least a portion of the portion of the current commanding structure; and
a second type pad disposed on a portion of an upper surface of the current commanding structure, wherein a contact resistance between the second type semiconductor layer and the current commanding structure is smaller than a contact resistance between the second type semiconductor layer and the second type pad.
2. The micro light-emitting device according to claim 1 , further comprising:
orthogonal projection area of the current commanding structure on the second type semiconductor layer is smaller than an orthogonal projection area of the second type pad on the second type semiconductor layer.
3. The micro light-emitting device according to claim 2 , wherein a first horizontal distance between the current commanding structure and the closest edge of the second type semiconductor layer is greater than a second horizontal distance between the second type pad and the closest edge of the second type semiconductor layer.
4. The micro light-emitting device according to claim 3 , wherein a ratio of the second horizontal distance to the first horizontal distance is in a range of 0.2 to 0.8.
5. The micro light-emitting device according to claim 1 , wherein an area of the current commanding structure exposed by the opening of the insulating layer is smaller than a contact area of the current commanding structure and the second type semiconductor layer.
6. The micro light-emitting device according to claim 1 , wherein the opening of the insulating layer exposes all of an upper surface of the current commanding structure.
7. A display apparatus, comprising:
a driving substrate comprising a plurality of pixel regions; and
a plurality of a micro light-emitting devices, each of the plurality of the micro light-emitting devices comprising:
an epitaxial structure, comprising:
a first type semiconductor layer;
a light-emitting layer disposed on the first type semiconductor layer; and
a second type semiconductor layer disposed on the light-emitting layer;
a first type pad disposed on the epitaxial structure and electrically connected to the first type semiconductor layer;
a current commanding structure disposed on the epitaxial structure and electrically connected to the second type semiconductor layer, wherein an orthogonal projection area of the current commanding structure on the second type semiconductor layer is smaller than a surface area of a surface of the second type semiconductor layer; and
an insulating layer contacting a portion of the current commanding structure and a portion of the surface of the second type semiconductor layer, wherein the insulating layer has an opening exposing at least a portion of the portion of the current commanding structure;
a first type electrode connection layer electrically connected the first type pad onto the driving substrate; and
a second type electrode connection layer electrically connected the current commanding structure onto the driving substrate, wherein a contact resistance between the second type semiconductor layer and the current commanding structure is smaller than a contact resistance between the second type semiconductor layer and the second type electrode connection layer, and at least one of the plurality of the micro light-emitting devices is disposed in each of the plurality of the pixel regions.
8. The display apparatus according to claim 7 , wherein the first type pad and the current commanding structure are away from the driving substrate, and the first type electrode connection layer and the second type electrode connection layer are electrically connected to the driving substrate from a side surface of the insulating layer.
9. The display apparatus according to claim 7 , wherein the first type electrode connection layer and the second type electrode connection layer are directly connected to at least a portion of the first type pad and at least a portion of the current commanding structure, respectively, a material of the first type pad is metal, and a material of the current commanding structure is a metal oxide.
10. The display apparatus according to claim 7 , wherein the second type electrode connection layer directly contacts all of an upper surface of the current commanding structure.
11. The display apparatus according to claim 10 , wherein the second type electrode connection layer is partially disposed in the insulating layer.
12. A micro light-emitting device, comprising:
an epitaxial structure, comprising:
a first type semiconductor layer;
a light-emitting layer disposed on the first type semiconductor layer; and
a second type semiconductor layer disposed on the light-emitting layer;
a first type pad disposed on the epitaxial structure and electrically connected to the first type semiconductor layer;
a second type pad disposed on the epitaxial structure and electrically connected to the second type semiconductor layer, wherein the first type pad and the second type pad are located on two opposite sides of the light-emitting layer; and
a current commanding structure disposed between the second type semiconductor layer and the second type pad, wherein the current commanding structure is a metal oxide, and the current commanding structure directly contacts one part of the second type semiconductor layer, wherein a contact resistance between the second type semiconductor layer and the current commanding structure is smaller than a contact resistance between the second type semiconductor layer and the second type pad, and a contact area between the current commanding structure and the second type semiconductor layer is greater than a contact area between the current commanding structure and the second type pad.