CN102683556A - White Light Emitting Diode with Fluorescent Layer - Google Patents

Abstract

The invention discloses a white light-emitting diode with a fluorescent layer, which comprises a gallium nitride buffer layer, an N-type gallium nitride layer, a multi-quantum well aluminum gallium nitride layer, a P-type gallium nitride layer, a transparent conductive layer and an indium oxide terbium fluorescent layer which are sequentially stacked on a sapphire substrate, and further comprises a positive metal connecting layer connected with the P-type gallium nitride layer and a negative metal connecting layer connected with the N-type gallium nitride layer, wherein when the positive electrode metal connecting layer and the negative electrode metal connecting layer are respectively connected with an external positive power supply end and a negative power supply end, the multiple quantum potential well aluminum gallium nitride layer can emit light due to electron hole recombination, and penetrates the P-type GaN layer, the transparent conductive layer, and the fluorescent layer of indium oxide terbium to generate an outgoing light to the outside, and the indium oxide terbium fluorescent layer has fluorescence and is used for converting light rays emitted by the multi-quantum-well AlGaN layer into emergent light of white light.

Description

White Light Emitting Diode with Fluorescent Layer

technical field

The invention relates to a white light emitting diode, in particular to a gallium nitride white light emitting diode having a transparent conductive layer of indium terbium oxide with fluorescent properties.

Background technique

Light-emitting diodes have been widely used in light-emitting sources and displays due to their high-efficiency light-emitting characteristics. The light-emitting principle of light-emitting diodes is to use the electron-hole recombination at the PN junction between the P-type semiconductor layer and the N-type semiconductor to convert electrical energy into corresponding light energy when forward biased, thus generating outgoing light. The wavelength of the emitted light depends on the size of the energy gap, so the appropriate composition of the P-type semiconductor layer and the N-type semiconductor can be used to achieve the required size of the energy gap, and then generate the required visible light.

The outgoing light produced by general light-emitting diodes has ultraviolet components, so the fluorescent effect of phosphor powder added in the transparent fluorescent colloid layer is often used to convert high-energy ultraviolet light into lower-energy visible light for use. However, the disadvantage of the above-mentioned prior art is that the transparent fluorescent colloid layer has the problem of colloid aging, which affects the quality of the light emitted by the light-emitting diode. Therefore, a white light-emitting diode with a semiconductor fluorescent layer having a fluorescent effect manufactured by a semiconductor process is required. , to solve the above-mentioned problems of the prior art.

Contents of the invention

The main purpose of the present invention is to provide a white light emitting diode with a fluorescent layer, including a sapphire substrate, a gallium nitride buffer layer, an N-type gallium nitride layer, a multi-quantum well aluminum gallium nitride layer, and a p-type gallium nitride layer , transparent conductive layer, indium terbium oxide fluorescent layer, negative metal connection layer and positive metal connection layer, of which gallium nitride buffer layer, N-type gallium nitride layer, multi-qubit well aluminum gallium nitride layer, P-type gallium nitride layer Layer, transparent conductive layer, and indium terbium oxide fluorescent layer are sequentially stacked on the sapphire substrate, while the negative metal connection layer is connected to the N-type gallium nitride layer to connect to the external negative power supply terminal, and the positive metal connection layer is located on the indium terbium oxide fluorescent layer. Layer and through the indium terbium oxide fluorescent layer and connected to the transparent conductive layer, used to connect the external positive power supply terminal, so that the current passes through the transparent conductive layer, P-type gallium nitride layer, aluminum gallium nitride multi-quantum from the positive metal connection layer Potential well layer, N-type gallium nitride layer to the negative electrode metal connection layer, and the multi-quantum well aluminum gallium nitride layer emits light, which penetrates the P-type gallium nitride layer, transparent conductive layer and indium terbium oxide fluorescent layer, And through the fluorescent indium terbium oxide fluorescent layer, it is converted into white light to emit to the outside.

Therefore, the light-emitting diode of the present invention does not need to add fluorescent powder to the transparent colloid to form a colloidal fluorescent layer in order to convert ultraviolet light into visible light, but can be directly deposited on the transparent conductive layer by using the semiconductor process of radio frequency reactive magnetron sputtering method. An indium terbium oxide fluorescent layer with fluorescent effect is formed to generate outgoing light with a white light spectrum.

Description of drawings

FIG. 1 is a schematic diagram of a white light emitting diode with a fluorescent layer of the present invention.

Fig. 2 is the light excitation spectrum of the white light emitting diode of the embodiment of the present invention.

FIG. 3 is a light excitation spectrum of a white light emitting diode according to another embodiment of the present invention.

Fig. 4 is the electric excitation spectrum of the white light emitting diode of the embodiment of the present invention.

FIG. 5 is an electrical excitation spectrum of a fluorescent layer of a white light emitting diode according to an embodiment of the present invention.

FIG. 6 is an electrical excitation spectrum of a white light emitting diode according to another embodiment of the present invention.

FIG. 7 is an electrical excitation spectrum of a fluorescent layer of a white light emitting diode according to another embodiment of the present invention.

Fig. 8 is a luminescence photo of the 10% TIO/GaN-based LED of the present invention, wherein the current is 20mA.

Fig. 9 is a luminescence photo of the 20% TIO/GaN-based LED of the present invention, wherein the current is 20mA.

Detailed ways

The implementation of the present invention will be described in more detail in conjunction with the drawings and component symbols in the description below, so that those skilled in the art can implement it after studying the description.

Referring to FIG. 1 , it is a schematic diagram of a white light emitting diode with a fluorescent layer of the present invention. As shown in FIG. 1 , the white light emitting diode with fluorescent layer of the present invention includes a sapphire substrate 10, a gallium nitride buffer layer 20, an N-type gallium nitride layer 30, and a multiple quantum well (Multiple Quantum Well, MQW) aluminum gallium nitride Layer 40, P-type GaN layer 50, transparent conductive layer 60, indium terbium oxide fluorescent layer 70, negative metal connection layer 80 and positive metal connection layer 90 are used to generate white light.

Gallium nitride buffer layer 20, N-type gallium nitride layer 30, multi-quantum well aluminum gallium nitride layer 40, P-type gallium nitride layer 50, transparent conductive layer 60 and indium terbium oxide fluorescent layer 70 are stacked on the sapphire layer in sequence. on the substrate 10 , and expose a part of the N-type GaN layer 30 for electrically connecting the negative metal connection layer 80 , and the negative metal connection layer 80 is connected to the negative terminal V- of the external power supply. The positive metal connection layer 90 is used to connect the positive terminal V+ of the external power supply, and is located on the indium terbium oxide fluorescent layer 70. The indium terbium oxide fluorescent layer 70 has a through hole, so the positive metal connection layer 90 can be electrically connected to the transparent conductive layer 60 .

The multi-quantum well AlGaN layer 40 has a plurality of alternately stacked thin AlGaN layers with different energy levels, and the quantum wells formed by the low energy levels can be used to make it easier for electrons and holes to be confined together. Thus, the luminous intensity can be increased.

When the current passes through the transparent conductive layer 60, the P-type gallium nitride layer 50, the multi-quantum well aluminum gallium nitride layer 40, and the N-type gallium nitride layer 30 from the positive metal connection layer 90 to the negative metal connection layer 80, more The quantum well AlGaN layer 40 emits light due to electron-hole recombination, and the light passes through the P-type GaN layer 50, the transparent conductive layer 60, and the indium terbium oxide fluorescent layer 70, and is fluorescent The indium terbium oxide fluorescent layer 70 is converted into white light emitted to the outside.

The indium terbium oxide fluorescent layer 70 of the present invention is a transparent film, and its main component includes indium terbium oxide (Terbium Indium Oxide), the chemical formula is In ₂ O ₃ : Tb, generally referred to as TIO, and the optimal ratio range of indium oxide to terbium In ₂ O ₃ :Tb=95:5 to 5:95. The indium terbium oxide fluorescent layer 70 can be deposited on the transparent conductive layer 60 by using a semiconductor process of radio frequency reactive magnetron sputtering.

Referring to Fig. 2 and Fig. 3, to clearly understand the characteristics of the present invention, wherein Fig. 2 is the photoluminescence spectrum (photoluminescence, PL) of the white light-emitting diode of the embodiment of the present invention, and the ratio of its indium oxide to terbium is 90:10, and 3 is a photoexcitation spectrum of a white light emitting diode according to another embodiment of the present invention, and the ratio of indium oxide to terbium is 80:20. Fig. 2 and Fig. 3 show the change of photoexcited fluorescence spectrum in the temperature range from 10K to 300K, and Fig. 2 and Fig. 3 show broad absorption characteristics around 575nm and 565nm respectively.

Referring to FIG. 4 and FIG. 5 , they are the electroluminescence (EL) spectra of the white light-emitting diode and its fluorescent layer of the embodiment of the present invention, respectively, and the ratio of indium oxide to terbium is 90:10, and the current is 100mA. It can be seen from FIG. 4 that the white light emitting diode of this embodiment has 385nm ultraviolet light. It can be seen from FIG. 5 that the fluorescent layer has an orbital transition from 450nm to 700nm, that is, a transition from D orbital to F orbital. And indicate the wavelength of the corresponding transition.

Next, referring to FIG. 6 and FIG. 7 , they are EL spectra of another embodiment of the present invention, the white light emitting diode and its fluorescent layer, and the ratio of indium oxide to terbium is 80:20, and the current is 100mA. In FIG. 6, the white light emitting diode also has 385nm ultraviolet light, and in FIG. 7, its fluorescent layer also has an orbital transition from 450nm to 700nm similar to that shown in FIG. 5, and the corresponding transition wavelengths are marked in the figure.

Therefore, it can be clearly understood from the spectra of FIG. 2 to FIG. 7 that the white light emitting diode of the present invention can indeed produce white light to provide a high-quality light source, and can be applied to a backlight source for a display or a general lighting source. In order to further show the specific performance of the above-mentioned white light emitting diode with a fluorescent layer of the present invention, please refer to the photos shown in Figure 8 and Figure 9, wherein Figure 8 is a fluorescent layer containing 10% indium terbium oxide (that is, the ratio of indium oxide to terbium 90:10) of a GaN white light emitting diode emitting white light, and Figure 9 is a photo of a GaN white light emitting diode containing 20% indium terbium oxide fluorescent layer (that is, the ratio of indium oxide to terbium is 80:20) emitting white light , and the conduction current is 20mA.

The above are only preferred embodiments for explaining the present invention, and are not intended to limit the present invention in any form. Therefore, any modification or change of the present invention made under the same principle of the invention, All should still be included in the category that the present invention intends to protect.

Claims (4)

1. the white light emitting diode of a tool fluorescence coating in order to produce the emergent light of white light, is characterized in that, comprises;

One sapphire substrate;

One gallium nitride resilient coating, storehouse is on this sapphire substrate;

One n type gallium nitride layer, storehouse is on this gallium nitride resilient coating;

The sub-potential trough aluminium gallium nitride alloy of volume layer, storehouse and expose the part of this n type gallium nitride layer on this n type gallium nitride layer;

One P type gallium nitride layer, storehouse is on the sub-potential trough aluminium gallium nitride alloy of this volume layer;

One transparency conducting layer, storehouse is on this P type gallium nitride layer;

One indium oxide terbium fluorescence coating, storehouse and have through hole on this transparency conducting layer;

One negative pole metal connecting layer, storehouse and are electrically connected to this transparency conducting layer through this through hole on this indium oxide terbium fluorescence coating, and this negative pole metal connecting layer gas is connected to a negative terminal of external power source; And

One cathode metal articulamentum, storehouse are on this P type gallium nitride layer, and this cathode metal articulamentum gas is connected to an anode of external power source.

2. white light emitting diode as claimed in claim 1 is characterized in that, said indium oxide terbium fluorescence coating comprises that the proportion of indium oxide and terbium is In ₂O ₃: Tb=95: 5 to 70: 30.

3. white light emitting diode as claimed in claim 1 is characterized in that, said indium oxide terbium fluorescence coating deposits with radio frequency reaction formula magnetic control sputtering plating method.

4. white light emitting diode as claimed in claim 1 is characterized in that, the sub-potential trough aluminium gallium nitride alloy of said volume layer has the thin shape aluminium gallium nitride alloy on a plurality of alternately storehouses and different abilities rank, and the formed quantum potential trough of low energy stratum.

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