Rod-like light-emitting device, method of manufacturing rod-like light-emitting device, backlight, illuminating device, and display device

1. A rod-like light-emitting device comprising:

a semiconductor core of a first conductivity type having a rod shape, the rod shape having a length and a circumference;

a semiconductor layer of a second conductivity type covering the semiconductor core so as to form a pn junction between the semiconductor core and the semiconductor layer coaxially with respect to the semiconductor core; and

a transparent electrode formed so as to cover substantially a whole of the semiconductor layer,

wherein the semiconductor core comprises an n-type semiconductor and the semiconductor layer comprises a p-type semiconductor,

wherein an outer peripheral surface of a part of the semiconductor core is exposed along the entire circumference of the rod shape, the exposed part having a part of the length of the rod shape, and

wherein the rod-like light-emitting device has a diameter within a range of from 10 nm to 5 μm, inclusive, and a length within a range of from 100 nm to 200 μm, inclusive.

2. A rod-like light-emitting device comprising:

a semiconductor core of a first conductivity type having a rod shape;

a cap layer covering only one of two longitudinal ends of the rod shape of the semiconductor core; and

a semiconductor layer of a second conductivity type covering an outer peripheral surface of a portion of the semiconductor core other than an exposed portion, the exposed portion of the semiconductor core being a portion opposite from a portion covered with the cap layer of the semiconductor core,

wherein the cap layer is made of a material having a higher electric resistance than the semiconductor layer.

3. The rod-like light-emitting device according to claim 2 , wherein a conductive layer having a lower resistance than the semiconductor layer is formed to cover the semiconductor layer.

4. A light-emitting apparatus comprising:

at least one rod-like light-emitting device according to claim 2 ; and

a substrate on which the rod-like light-emitting device is mounted such that a longitudinal direction of the rod-like light-emitting device is parallel to a mounting surface of the substrate,

wherein electrodes are formed, with a predetermined spacing therebetween, on the substrate, and

wherein the exposed portion at the one end of the semiconductor core of the rod-like light-emitting device is connected to one of the electrodes on the substrate, and the semiconductor layer at the other end of the semiconductor core on which the cap layer is provided is connected to another one of the electrodes on the substrate.

5. A light-emitting apparatus comprising:

at least one rod-like light-emitting device according to claim 3 ; and

a substrate on which the rod-like light-emitting device is mounted such that a longitudinal direction of the rod-like light-emitting device is parallel to a mounting surface of the substrate,

wherein electrodes are formed, with a predetermined spacing therebetween, on the substrate, and

wherein the exposed portion at the one end of the semiconductor core of the rod-like light-emitting device is connected to one of the electrodes on the substrate, and the conductive layer on the other side of the semiconductor core on which the cap layer is provided is connected to another one of the electrodes on the substrate.

6. A rod-like light-emitting device comprising:

a semiconductor core of a first conductivity type having a rod shape; and

a semiconductor layer of a second conductivity type covering an outer peripheral surface of a portion of the semiconductor core other than an exposed portion, the exposed portion of the semiconductor core being one end portion of the semiconductor core,

wherein a step portion is provided between an outer peripheral surface of the exposed portion not covered with the semiconductor layer of the semiconductor core and an outer peripheral surface of a covered portion covered with the semiconductor layer of the semiconductor core.

7. The rod-like light-emitting device according to claim 6 , further comprising a conductive layer formed to cover the semiconductor layer and made of a material having a lower electric resistance than the semiconductor layer.

8. A light-emitting apparatus comprising:

at least one rod-like light-emitting device according to claim 6 ; and

a substrate on which the rod-like light-emitting device is mounted such that a longitudinal direction of the rod-like light-emitting device is parallel to a mounting surface of the substrate,

wherein electrodes are formed, with a predetermined spacing therebetween, on the substrate, and

wherein the exposed portion at the one end of the semiconductor core of the rod-like light-emitting device is connected to one of the electrodes on the substrate, and the semiconductor layer at the other end of the semiconductor core is connected to another one of the electrodes on the substrate.

9. A light-emitting apparatus comprising:

at least one rod-like light-emitting device according to claim 7 ; and

a substrate on which the rod-like light-emitting device is mounted such that a longitudinal direction of the rod-like light-emitting device is parallel to a mounting surface of the substrate,

wherein electrodes are formed, with a predetermined spacing therebetween, on the substrate, and

wherein the exposed portion at the one end of the semiconductor core of the rod-like light-emitting device is connected to one of the electrodes on the substrate, and the conductive layer on the other side of the semiconductor core is connected to another one of the electrodes on the substrate.

10. A rod-like light-emitting device comprising:

a semiconductor core of a first conductivity type having a rod shape;

a semiconductor layer of a second conductivity type covering one of two ends of the semiconductor core;

an insulator covering an outer peripheral surface, not covered with the semiconductor layer, of the semiconductor core; and

an underlying layer of the first conductivity type adjoining the other end of the semiconductor core, wherein an end surface of the underlying layer axially opposite from the semiconductor core and a peripheral surface of the underlying layer are exposed.

11. A light-emitting apparatus comprising:

a rod-like light-emitting device including a semiconductor core of a first conductivity type having a rod shape, the rod shape having a length and a circumference, a semiconductor layer of a second conductivity type formed to cover the semiconductor core so as to form a pn junction between the semiconductor core and the semiconductor layer coaxially with respect to the semiconductor core, and a transparent electrode formed so as to cover substantially a whole of the semiconductor layer, wherein the semiconductor core comprises an n-type semiconductor and the semiconductor layer comprises a p-type semiconductor, an outer peripheral surface of a part of the semiconductor core is exposed along the entire circumference of the rod shape, the exposed part having a part of the length of the rod shape, and the rod-like light-emitting device has a diameter within a range of from 10 nm to 5 μm, inclusive, and a length within a range of from 100 nm to 200 μm, inclusive; and

a substrate on which the rod-like light-emitting device is mounted such that a longitudinal direction of the rod-like light-emitting device is parallel to a mounting surface of the substrate.

12. A rod-like light-emitting device comprising:

a semiconductor core of a first conductivity type having a rod shape, the rod shape having a length and a circumference;

a semiconductor layer of a second conductivity type covering the semiconductor core so as to form a pn junction between the semiconductor core and the semiconductor layer coaxially with respect to the semiconductor core; and

a transparent electrode formed so as to cover substantially a whole of the semiconductor layer,

wherein the semiconductor core comprises an n-type semiconductor and the semiconductor layer comprises a p-type semiconductor,

wherein the semiconductor core has, along the length of the rod shape, a first portion having an outer peripheral surface which is entirely covered with the semiconductor layer of the second conductivity type along the entire circumference of the rod shape, and a second portion having an outer peripheral surface which is at least partially exposed along at least part of the circumference of the rod shape without being covered with the semiconductor layer of the second conductivity type, and

wherein the rod-like light-emitting device has a diameter within a range of from 10 nm to 5 μm, inclusive, and a length within a range of from 100 nm to 200 μm, inclusive.

13. A rod-like light-emitting device comprising:

a semiconductor core of a first conductivity type having a rod shape, the rod shape having a length and a circumference; and

a semiconductor layer of a second conductivity type covering the semiconductor core,

wherein an outer peripheral surface of a part of the semiconductor core is exposed along the entire circumference of the rod shape, the exposed part having a part of the length of the rod shape,

wherein an outer peripheral surface of one of two longitudinal end portions of the semiconductor core is exposed, and

wherein an end surface of the other of the two longitudinal end portions of the semiconductor core is covered with the semiconductor layer.

14. The rod-like light-emitting device according to claim 13 , a thickness of the semiconductor layer in a longitudinal, or axial direction of the rod shape at a part covering the end surface of the other of the two longitudinal end portions of the semiconductor core is larger than a thickness thereof in a radial direction of the rod shape at a part covering the outer peripheral surface of the semiconductor core.

15. An illuminating device including the rod-like light-emitting device according to claim 1 .

16. A display device including the rod-like light-emitting device according to claim 1 .