EP-4739045-A1 - LIGHT-EMITTING DEVICE AND DISPLAY DEVICE INCLUDING THE SAME

EP4739045A1EP 4739045 A1EP4739045 A1EP 4739045A1EP-4739045-A1

Abstract

A light-emitting device may comprise a light-emitting unit including light-emitting structures that are sequentially stacked, wherein each of the light-emitting structures includes a first conductivity-type semiconductor layer, an active layer, and a second conductivity-type semiconductor layer that are sequentially stacked. The light-emitting device may further include individual electrodes in contact with the first conductivity-type semiconductor layers of the light-emitting structures and on a lower surface of the light-emitting unit. At least one, preferably at least two of the individual electrodes may have a conductive via structure. A common electrode, which is in contact with side surfaces of the second conductivity-type semiconductor layers of the light-emitting structures, may be arranged on a side surface of the light-emitting unit. Side surfaces of the first conductivity-type semiconductor layers and the active layers of the light-emitting structures may be insulated from the common electrode by an insulating layer.

Inventors

OH, YOUNGTEK
KIM, JOOSUNG
PARK, JOONYONG
SHIN, DONGCHUL
HAN, JOOHUN
HWANG, KYUNGWOOK
HWANG, JUNSIK
SONG, SANGHOON
YU, MINCHUL

Assignees

Samsung Electronics Co., Ltd.

Dates

Publication Date: 20260506
Application Date: 20250617

Claims (14)

A light-emitting device comprising: a light-emitting unit comprising a first light-emitting structure, a second light-emitting structure, and a third light-emitting structure that are sequentially stacked and configured to emit light of respective, different wavelengths, wherein each of the first light-emitting structure, the second light-emitting structure, and the third light-emitting structure comprises a first conductivity-type semiconductor layer, an active layer, and a second conductivity-type semiconductor layer that are sequentially stacked; a first individual electrode on a lower surface of the light-emitting unit and in contact with the first conductivity-type semiconductor layer of the first light-emitting structure; a second individual electrode on the lower surface of the light-emitting unit and in contact with the first conductivity-type semiconductor layer of the second light-emitting structure; a third individual electrode on the lower surface of the light-emitting unit and in contact with the first conductivity-type semiconductor layer of the third light-emitting structure; a common electrode on a side surface of the light-emitting unit and in contact with side surfaces of the second conductivity-type semiconductor layer of each of the first light-emitting structure, the second light-emitting structure, and the third light-emitting structure; and an insulating layer that insulates, from the common electrode, side surfaces of the first conductivity-type semiconductor layer and the active layer of each of the first light-emitting structure, the second light-emitting structure, and the third light-emitting structure; wherein at least one, preferably at least two from among the first individual electrode, the second individual electrode, and the third individual electrode, comprises a conductive via structure; characterized in that the common electrode comprises a transparent electrode material.
The light-emitting device according to the previous claim, wherein the side surfaces of the first conductivity-type semiconductor layer and the active layer of each of the first light-emitting structure, the second light-emitting structure, and the third light-emitting structure are concavely stepped inward from the side surfaces of the second conductivity-type semiconductor layer of each of the first light-emitting structure, the second light-emitting structure, and the third light-emitting structure.
The light-emitting device according to the previous claim, wherein a length by which the side surfaces of the first conductivity-type semiconductor layer and the active layer of each of the first light-emitting structure, the second light-emitting structure, and the third light-emitting structure are stepped inward from the side surfaces of the second conductivity-type semiconductor layer of each of the first light-emitting structure, the second light-emitting structure, and the third light-emitting structure, is 0.5 µm or less.
The light-emitting device according to any one of the previous claims, wherein the common electrode surrounds said side surface of the light-emitting unit.
The light-emitting device according to any one of the previous claims, wherein the common electrode extends on to an upper surface of the light-emitting unit.
The light-emitting device according to any one of the previous claims, wherein the first individual electrode comprises a first electrode pad that is in contact with a lower surface of the first conductivity-type semiconductor layer of the first light-emitting structure, wherein the second individual electrode comprises: a second electrode pad that is on the lower surface of the light-emitting unit; and a conductive via that electrically connects the second electrode pad to the first conductivity-type semiconductor layer of the second light-emitting structure, and wherein the third individual electrode comprises: a third electrode pad that is on the lower surface of the light-emitting unit; and a conductive via that electrically connects the third electrode pad to the first conductivity-type semiconductor layer of the third light-emitting structure.
The light-emitting device according to any one of the previous claims 1-5, wherein the first individual electrode comprises: a first electrode pad on the lower surface of the light-emitting unit; and a first conductive via that electrically connects the first electrode pad to the first conductivity-type semiconductor layer of the first light-emitting structure; the second individual electrode comprises: a second electrode pad on the lower surface of the light-emitting unit; and a second conductive via that electrically connects the second electrode pad to the first conductivity-type semiconductor layer of the second light-emitting structure; and the third individual electrode comprises: a third electrode pad on the lower surface of the light-emitting unit; and a third conductive via that electrically connects the third electrode pad to the first conductivity-type semiconductor layer of the third light-emitting structure.
The light-emitting device according to any one of the previous claims, further comprising: a reflective layer that surrounds said side surface of the light-emitting unit; and a passivation layer that insulates the common electrode from the reflective layer.
The light-emitting device according to any one of the previous claims, wherein said side surface of the light-emitting unit is parallel to a direction in which the first light-emitting structure, the second light-emitting structure, and the third light-emitting structure are stacked.
The light-emitting device according to any one of the previous claims, wherein said side surface of the light-emitting unit is inclined such as to gradually expand outward from the first light-emitting structure toward the third light-emitting structure.
The light-emitting device according to any one of the previous claims, further comprising a scattering pattern on an upper surface of the light-emitting unit; and/or further comprising a lens on an upper surface of the light-emitting unit.
The light-emitting device according to any one of the previous claims, wherein the third light-emitting structure is configured to emit red light, and wherein preferably the third light-emitting structure is the uppermost from among the first, second and third light-emitting structures.
The light-emitting device according to the previous claim, wherein the first light-emitting structure and the second light-emitting structure are configured to emit blue light and green light, respectively.
A display device comprising: a display panel comprising: a plurality of light-emitting devices according to any one of the previous claims; a driver circuit configured to switch the plurality of light-emitting devices on and off; and a controller configured to input on-off switching signals for the plurality of light-emitting devices to the driver circuit according to an image signal.

Description

TECHNICAL FIELD The present disclosure relates to a light-emitting device and a display device including the same. BACKGROUND Light-emitting devices such as, for example, light-emitting diodes (LEDs), are known as next-generation light sources having advantages such as long lifespan, low power consumption, fast response time, and environmental friendliness compared to related-art light sources. In light of these advantages, the industrial demand for light-emitting devices is increasing. LEDs are typically applied and used in various products such as lighting devices or display devices. Recently, ultra-small LEDs on the microscale or nanoscale have been developed. Such devices are referred to as micro-LEDs. Micro-LEDs have been applied to relatively large display devices such as televisions, and furthermore, their application to small display devices, such as displays for augmented reality (AR) devices, has been attempted. Micro-LEDs applied to small display devices are significantly small on the order of a few micrometers, making it difficult to secure a large light emission area. In particular, in micro-LEDs where red-green-blue (RGB) sub-pixels are vertically arranged, the light emission area is reduced due to electrodes for driving the respective sub-pixels, which may lower the light emission efficiency of the micro-LEDs. SUMMARY According to embodiments of the present disclosure, a light-emitting device with improved light emission efficiency and a display device including the light-emitting device are provided. According to a first aspect, a light-emitting device may be provided and include: a light-emitting unit including a first light-emitting structure, a second light-emitting structure, and a third light-emitting structure that are sequentially stacked and configured to emit light of respective, different wavelengths, wherein each of the first light-emitting structure, the second light-emitting structure, and the third light-emitting structure includes a first conductivity-type semiconductor layer, an active layer, and a second conductivity-type semiconductor layer that are sequentially stacked; a first individual electrode on a lower surface of the light-emitting unit and in contact with the first conductivity-type semiconductor layer of the first light-emitting structure; a second individual electrode on the lower surface of the light-emitting unit and in contact with the first conductivity-type semiconductor layer of the second light-emitting structure; a third individual electrode on the lower surface of the light-emitting unit and in contact with the first conductivity-type semiconductor layer of the third light-emitting structure; a common electrode on a side surface of the light-emitting unit and in contact with side surfaces of the second conductivity-type semiconductor layer of each of the first light-emitting structure, the second light-emitting structure, and the third light-emitting structure; and an insulating layer that insulates, from the common electrode, side surfaces of the first conductivity-type semiconductor layer and the active layer of each of the first light-emitting structure, the second light-emitting structure, and the third light-emitting structure, wherein at least two from among the first individual electrode, the second individual electrode, and the third individual electrode include a conductive via structure. According to one or more embodiments of the present disclosure, the side surfaces of the first conductivity-type semiconductor layer and the active layer of each of the first light-emitting structure, the second light-emitting structure, and the third light-emitting structure may be concavely stepped inward from side surfaces of the second conductivity-type semiconductor layer of each of the first light-emitting structure, the second light-emitting structure, and the third light-emitting structure. According to one or more embodiments of the present disclosure, a length by which the side surfaces of the first conductivity-type semiconductor layer and the active layer of each of the first light-emitting structure, the second light-emitting structure, and the third light-emitting structure are stepped from the side surface of the second conductivity-type semiconductor layer of each of the first light-emitting structure, the second light-emitting structure, and the third light-emitting structure may be 0.5 µm or less. According to one or more embodiments of the present disclosure, the common electrode may surround the side surface of the light-emitting unit. According to one or more embodiments of the present disclosure, the common electrode may extend on to an upper surface of the light-emitting unit. According to one or more embodiments of the present disclosure, the common electrode may include a transparent electrode material. According to one or more embodiments of the present disclosure, the first individual electrode may include a first electrode pad that i