LIGHT EMITTING DEVICE AND METHOD OF PRODUCING A LIGHT EMITTING DEVICE

Abstract

To provide a DC drive type inorganic light emitting device excellent in luminous efficiency, provided is a light emitting device, including: a substrate; and a first layer and a second layer laminated on the substrate, in which the second layer is formed of a first portion containing Zn and at least one element chosen from S and Se as its constituent elements; and a second portion containing at least one element chosen from Cu and Ag and at least one element chosen from S and Se as its constituent elements; the first layer is made of a light emitting layer formed of at least one element chosen from S and Se and of Zn; and, in the second layer, the second portion has a cross section parallel to the substrate which tapers toward the first layer.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a sectional view schematically showing an example of the structure of a light emitting device as an embodiment of the present invention.

FIG. 2 is a sectional view schematically showing an example of the structure of the light emitting device as the embodiment of the present invention.

FIGS. 3A and 3B are schematic sectional views taken along the broken lines of FIG. 1, respectively.

FIG. 4 is a graph showing the film deposition rate of a constituent element of the light emitting device as the embodiment of the present invention.

FIG. 5 is a graph showing the film deposition rate of a constituent element of the light emitting device as the embodiment of the present invention.

FIG. 6 is a schematic sectional view showing the constitution of the light emitting device as the embodiment of the present invention.

FIG. 7 is a graph showing the film deposition rate of a constituent element of the light emitting device as the embodiment of the present invention.

Claims

1. A light emitting device, comprising: a substrate; anda first layer and a second layer laminated on the substrate, wherein:the second layer is formed of:a first portion containing Zn and at least one element chosen from S and Se as its constituent elements; anda second portion containing at least one element chosen from Cu and Ag and at least one element chosen from S and Se as its constituent elements;the first layer is a light emitting layer formed of at least one element chosen from S and Se and of Zn; andin the second layer, the second portion has a cross section parallel to the substrate which tapers toward the first layer.

2. A light emitting device according to claim 1, wherein the first layer contains at least one element chosen from Cu and Ag and at least one element selected from Al, Ga, and In.

3. A light emitting device according to claim 1, wherein the second portion further contains at least one element selected from Al, Ga, and In.

4. A light emitting device according to claim 1, wherein the second portion has a crystalline structure of a chalcopyrite structure.

5. A light emitting device according to claim 1, wherein: the first portion contains Zn and S as its constituent elements;the second portion contains Al, Cu, and S as its constituent elements;the first layer contains Zn and S as its constituent elements; andAl and Cu are added to the first layer.

6. A light emitting device according to claim 1, wherein: the first portion contains Zn and S as its constituent elements;the second portion contains Cu, and S as its constituent elements;the first layer contains Zn and S as its constituent elements; andAl and Cu are added to the first layer.

7. A light emitting device according to claim 1, wherein the light emitting device is structured so that light generated from the first layer is extracted to an outside of the light emitting device from the second layer.

8. A light emitting device according to claim 1, wherein a layer formed of a p-type semiconductor is provided to be adjacent to the second layer.

9. A method of producing a light emitting device in which a first layer and a second layer are provided to be adjacent to each other on a substrate, the method comprising: forming the first layer containing Zn and at least one element chosen from S and Se; andforming the second layer containing at least one element chosen from S and Se, at least one element chosen from Cu and Ag, and Zn,wherein at least one of a feeding amount of the at least one element chosen from Cu and Ag and a feeding amount of Zn is changed with time.

10. A method of producing a light emitting device in which a first layer and a second layer are provided to be adjacent to each other on a substrate, the method comprising: forming the first layer containing Zn and at least one element chosen from S and Se; andforming the second layer containing at least one element chosen from S and Se, at least one element chosen from Cu and Ag, and Zn, wherein:at least one of a feeding amount of the at least one element chosen from Cu and Ag and a feeding amount of Zn is changed with time; andthe second layer is distributed being separated into a first portion containing Zn and at least one element chosen from S and Se as its constituent elements, and a second portion containing the at least one element chosen from Cu and Ag and the at least one element chosen from S and Se as its constituent elements, and is formed so that the second portion has a cross section parallel to the substrate which tapers toward the first layer.