JPH03205782A - Electroluminescence element - Google Patents

Abstract

PURPOSE:To obtain an electroluminescence element with high luminous efficiency and high-intensity luminescence by providing a P-type compound semiconductor layer between a luminous layer and an insulating layer. CONSTITUTION:A P-type compound semiconductor layer 8 is provided between a luminous layer 4 and the second insulating layer 5, and the P-type compound semiconductor layer 8 is made of aluminum nitride (AIN) with a high content of aluminum, for example. Carriers of the P-type compound semiconductor layer 8 are captured by the well-type potential formed between the luminous layer 4 and the second insulating layer 5 and accumulated on the P-type compound semiconductor layer 8. When the P-type compound semiconductor layer 8 is provided, a remarkably large quantity of the carriers excite the luminescence center, and the number of collisions between the carriers and the luminescence center is increased. Luminous efficiency and luminous intensity can be improved.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] This invention relates to an electroluminescent device.

E. Prior Art FIG. 3 shows the basic configuration of a conventionally used electroluminescent element. A transparent conductive film 2 such as an ITO (indium tin oxide) film is formed on the surface of a glass substrate 1, and a lth insulating layer 3 is formed on this transparent conductive film 2. Then, zinc sulfide (Zn
A light emitting layer 4 made of a material such as S:Mn) and a second insulating layer 5 are laminated in order, and the light emitting layer 4 is sandwiched between the first and second insulating layers 3 and 5. A back electrode 6 made of aluminum or the like is formed on the second insulating layer 5, and a high frequency power source 7 is connected between the back electrode 6 and the transparent conductive film 2. The first insulating layer 3 is made of silicon oxide (
The second insulating layer 5
For example, silicon nitride film and aluminum oxide (Alz○
3) It is composed of a laminated structure film with a film.

When a high frequency voltage from a high frequency voltage source a7 is applied between the transparent conductive film 2 and the back electrode 6, carriers trapped at the interface between the light emitting layer 4 and the insulating layer 3.5 are removed from the light emitting layer 4.
collides with the luminescent center of and excites this luminescent center. Light is then emitted when this excited luminescent center transitions to the ground state. This light is transmitted through the glass substrate 1 and observed, and a display is performed in this manner.

(Problems to be Solved by the Invention) In the electroluminescent element as described above, carriers contributing to light emission are carriers trapped between the light emitting layer 4 and the insulating layers 3 and 5, and only a very small amount The luminescent center is simply excited by the carriers, and therefore there are problems in that the luminous efficiency is poor and the brightness is low.

An object of the present invention is to solve the above-mentioned technical problems and provide an electroluminescent element that has high luminous efficiency and is capable of emitting high-intensity light.

[Means to solve the problem]

The electroluminescent device of the present invention is characterized in that a P-type compound semiconductor layer is interposed between the light emitting layer and the insulating layer.

[Effect]

According to the configuration of the present invention, the carriers accumulated in the P-type compound semiconductor layer are supplied to the light emitting layer, and the carriers collide with the light emission center and are excited, so the number of carriers contributing to light emission increases, As a result, luminous efficiency and luminance are improved.

〔Example〕

FIG. 1 is a sectional view showing the basic structure of an electroluminescence device according to an embodiment of the present invention. In FIG. 1, parts corresponding to those shown in FIG. 3 described above are designated by the same reference numerals.

In the electroluminescent device of this example, a P-type compound semiconductor layer 8 is provided between the light emitting layer 4 and the second insulating layer 5. The P-type compound semiconductor layer 8 is made of, for example, aluminum nitride (AI!.N
), boron nitride (BN) with a high boron content, etc., and carriers in this P-type compound semiconductor layer 8 are absorbed by the light-emitting layer 4 when no voltage is applied.
and the second insulating layer 5, and is trapped in the P-type compound semiconductor layer.

Figure 2 shows the structure of the hand. In FIG. 2, the P-type compound semiconductor layer 8 has surplus holes H that serve as carriers. That is, holes H exist between the light emitting layer 4 and the second insulating layer 5. When a voltage is applied to this, holes H are supplied into the light emitting layer 4 as indicated by the arrow in the figure. This hole H collides with the luminescent center and excites it. On the other hand, by applying a reverse voltage, the holes H return to their original state. Therefore, light emission is sustained by applying an alternating voltage. By providing the P-type compound semiconductor layer in this way, the number of carriers that excite the luminescent center is much larger than in the conventional structure, which increases the number of collisions between carriers and the luminescent center, thereby increasing the luminous efficiency. Furthermore, the luminance of light emission is significantly improved.

The shape of the P-type compound semiconductor layer 8 can be very easily formed using a film method that combines ion irradiation and vacuum deposition. For example, AIV. Lynch's AffiN can be manufactured by keeping the metal deposition rate constant and changing the amount of N ions, or by keeping the amount of N ions constant and changing the metal deposition rate, so that N/Affi<l. All you have to do is put it in a state where it becomes effective. Furthermore, by setting N/A N = 1, an insulator can be formed. If you want to make a BN for B-linochi, you can do it in the same way. By using such a certain film method, the P-type compound semiconductor layer 8 and the second
Since continuous processing with the insulating layer 5 is possible, very efficient production can be achieved.

In the embodiment, the P-type compound semiconductor layer 8 was provided between the light emitting layer 4 and the second insulating layer 5, but it may also be provided between the light emitting layer 4 and the first insulating layer 3, or between the light emitting layer 4 and the second insulating layer 5. It may be provided both between the insulating layers 5 and between the light emitting layer 4 and the first insulating layer 3.

〔Effect of the invention〕

As described above, according to the electroluminescent device of the present invention, the number of carriers contributing to light emission increases and the number of collisions between the light emission center and the carriers increases, so that the light emission efficiency is improved and high brightness is achieved. This makes it possible to emit light.

[Brief explanation of drawings]

Fig. 1 is a cross-sectional view showing the basic structure of an electroluminescent device according to an embodiment of the present invention, Fig. 2 is an explanatory view of its light emitting process, and Fig. 3 is a cross-sectional view showing the prior art. . 3...First insulating layer, 4...Light emitting layer, 5...Second insulating layer, 8...P-type compound semiconductor layer 1 FIG. 7H FIG.

Claims (1)

[Claims] An electroluminescence element having a conductive layer provided on both sides of a light emitting layer with an insulating layer interposed therebetween, characterized in that a P-type compound semiconductor layer is provided between the light emitting layer and the insulating layer. element.