CN105514235A - Multiple-quantum well structure for optoelectronic device - Google Patents

Abstract

The invention relates to a multiple quantum well structure for optoelectronic devices, which is applied to gallium nitride-based optoelectronic devices. The optoelectronic devices include an N-type semiconductor layer from a substrate to a surface layer, a multiple quantum well layer, a P-type electron blocking layer and P-type semiconductor layer; the multiple quantum well layer is formed by overlapping potential barrier layers and potential well layers. In the multiple quantum well layer structure, the indium composition or thickness of the potential well layer closest to the P-type semiconductor layer is smaller than other Potential well layer, which can compensate the potential well layer closest to the P-type semiconductor layer due to the influence of the electron blocking layer’s electric field, and improve the problem that the bandgap tilt is larger than other potential well layers, and use engineering adjustment methods to achieve effective improvement. Luminescent purity of GaN-based optoelectronic devices.

Description

A Multiple Quantum Well Structure for Optoelectronic Devices

【Technical field】

The invention relates to a photoelectric device structure technology, in particular to a multiple quantum well structure used in a photoelectric device.

【Background technique】

Multiple quantum wells and electron blocking layers are two structures widely used in gallium nitride-based optoelectronic devices. Compared with traditional double heterojunction optoelectronic devices, multiple quantum well optoelectronic devices have the advantage of higher luminous efficiency, while The electron blocking layer can increase the recombination probability of electrons and holes in the multiple quantum wells to improve the luminous efficiency.

The multiple quantum well structure of gallium nitride-based optoelectronic devices is formed by overlapping two materials with different band gaps. The potential well layer is generally indium gallium nitride, and the barrier layer is generally gallium nitride. Because the potential well layer The difference in lattice constant between the material and the barrier layer causes stress between the two, which will generate a piezoelectric field and cause the band gap edge of the quantum well to change from a square to a triangle, which is lower on the p-type gallium nitride side and n The side of GaN-type GaN is higher, so that the width of the band gap between the conduction band and the valence band becomes smaller, resulting in a longer emission wavelength.

In addition, on the side adjacent to the p-type gallium nitride of the multiple quantum well structure of the gallium nitride-based optoelectronic device, an electron blocking layer made of aluminum gallium nitride is generally grown to reduce the overflow of electrons to the p-type gallium nitride; As shown in Figure 1, because the electron blocking layer (AlGaN) and the potential well layer (InGaN) have a greater difference in lattice constant, the pressure on the last potential well layer of the multiple quantum well structure will be The electric field is larger than the other potential well layers, so that the last potential well layer emits light with a longer wavelength than the other potential well layers, which will affect the optical purity of the optoelectronic device.

【Content of invention】

In order to solve the deficiencies of the prior art, the invention provides a multiple quantum well structure capable of effectively improving the light emission purity of photoelectric devices.

In order to realize the above-mentioned purpose of the invention, the technical scheme adopted in the present invention is:

A multiple quantum well structure for a photoelectric device, the photoelectric device includes an N-type semiconductor layer from a substrate to a surface layer, a multiple quantum well layer, a P-type electron blocking layer and a P-type semiconductor layer; the multiple quantum well layer is composed of The potential barrier layer and the potential well layer overlap, and in the multiple quantum well layer structure, the indium composition or thickness of the potential well layer closest to the P-type semiconductor layer is smaller than that of other potential well layers.

Preferably, the barrier layer is gallium nitride.

Preferably, the potential well layer is InGaN.

Preferably, the P-type electron blocking layer is aluminum gallium nitride.

Preferably, the potential well layer closest to the P-type semiconductor layer uses an engineering method to adjust the indium composition of the potential well layer, so that the bandgap width of the potential well layer is larger than that of other potential well layers.

Preferably, the bandgap width of the potential well layer closest to the P-type semiconductor layer is greater than the bandgap width of other potential well layers by 0.01 eV to 0.1 eV.

Preferably, the potential well layer closest to the P-type semiconductor layer is used to adjust the thickness of the potential well layer by an engineering method, so that the thickness of the potential well layer is smaller than that of other potential well layers.

Preferably, the thickness of the potential well layer closest to the P-type semiconductor layer is smaller than the thickness of other potential well layers within a range of 0.05 nm to 0.5 nm.

The beneficial effects of the present invention are:

The present invention utilizes the engineering adjustment method, in the multi-quantum well layer structure, adjusts the indium composition or thickness of the potential well layer closest to the P-type semiconductor layer to be smaller than other potential well layers, so that the bandgap of the potential well layer closest to the P-type semiconductor layer The width is 0.01 eV to 0.1 eV larger than other potential well layers, or the thickness of the potential well layer closest to the P-type semiconductor layer is smaller than other potential well layers at 0.05 nanometers to 0.5 nanometers, so that the compensation closest to the P-type semiconductor layer The potential well layer is affected by the electric field of the electron blocking layer, which improves the problem that the band gap slope is larger than that of other potential well layers, so as to effectively improve the luminous purity of the GaN-based optoelectronic device.

【Description of drawings】

Fig. 1 is a schematic diagram of the multiple quantum well bandgap structure of gallium nitride-based optoelectronic devices in the prior art;

2 is a schematic diagram of a multiple quantum well bandgap structure of a GaN-based optoelectronic device according to an embodiment of the present invention;

Fig. 3 is a schematic diagram of a multiple quantum well bandgap structure of a GaN-based optoelectronic device according to an embodiment of the present invention.

【detailed description】

Embodiment one

A multiple quantum well structure for a photoelectric device, as shown in Figure 2, the photoelectric device includes an N-type semiconductor layer from a substrate to a surface layer, a multiple quantum well layer, a P-type electron blocking layer and a P-type semiconductor layer; The multiple quantum well layer is formed by overlapping barrier layers and potential well layers, wherein the barrier layer is gallium nitride, the potential well layer is indium gallium nitride, and the P-type electron blocking layer is aluminum gallium nitride; In the quantum well layer structure, the potential well layer closest to the P-type semiconductor layer uses engineering methods to adjust the indium composition of the potential well layer, so that the bandgap width of the potential well layer is larger than that of other potential well layers. Among them, the potential well layer closest to the P-type semiconductor layer The bandgap width of the potential well layer is greater than that of other potential well layers, and the range is between 0.01 electron volts and 0.1 electron volts, which can compensate for the influence of the piezoelectric field of the electron blocking layer on the potential well layer closest to the P-type semiconductor layer. , adjust the problem that the bandgap tilt is larger than other potential well layers, and improve the luminous purity of gallium nitride-based optoelectronic devices.

Embodiment two

The only difference between this embodiment and Embodiment 1 is that, as shown in Figure 3, in the multiple quantum well layer structure, the potential well layer closest to the P-type semiconductor layer uses an engineering method to adjust the thickness of the potential well layer, so that the potential The thickness of the well layer is smaller than other potential well layers, wherein, the thickness of the potential well layer closest to the P-type semiconductor layer is less than the amplitude of the thickness of other potential well layers between 0.05 nanometers and 0.5 nanometers, so that it can compensate for the thickness of the potential well layer closest to the P-type semiconductor layer. Because the potential well layer is affected by the piezoelectric field of the electron blocking layer, it also adjusts the problem that the bandgap tilt is larger than that of other potential well layers. It is also effective in improving the luminous purity of gallium nitride-based optoelectronic devices.

Through the above embodiments, using engineering adjustment, in the multiple quantum well layer structure, the indium composition or thickness of the potential well layer closest to the P-type semiconductor layer is adjusted to be smaller than other potential well layers, so that the potential well layer closest to the P-type semiconductor layer The bandgap width of the well layer is greater than that of other potential well layers by 0.01 electron volts to 0.1 electron volts, or the thickness of the potential well layer closest to the P-type semiconductor layer is smaller than that of other potential well layers at 0.05 nanometers to 0.5 nanometers to compensate for the Because the potential well layer of the type semiconductor layer is affected by the electric field of the electron blocking layer, the problem that the band gap inclination is larger than that of other potential well layers is improved, so as to effectively improve the luminous purity of the gallium nitride-based optoelectronic device.

The above-mentioned embodiments are only preferred embodiments of the present invention, and are not intended to limit the implementation scope of the present invention. All equivalent changes made according to the principle of the present invention shall fall within the scope of protection of the present invention.

Claims (8)

1. A multiple quantum well structure for optoelectronic device, which optoelectronic device comprises N-type semiconductor layer, multiple quantum well layer, P-type electron blocking layer and P-type semiconductor layer from substrate to surface layer; It is characterized in that: The multiple quantum well layer is formed by overlapping potential barrier layers and potential well layers. In the multiple quantum well layer structure, the indium composition or thickness of the potential well layer closest to the P-type semiconductor layer is smaller than that of other potential well layers. 2 . A multiple quantum well structure for optoelectronic devices according to claim 1 , wherein the barrier layer is gallium nitride. 3 . 3. A multiple quantum well structure for optoelectronic devices according to claim 1, characterized in that the potential well layer is InGaN. 4. A multiple quantum well structure for optoelectronic devices according to claim 1, characterized in that the P-type electron blocking layer is aluminum gallium nitride. 5. A kind of multiple quantum well structure for optoelectronic device according to claim 1, it is characterized in that, the potential well layer closest to the P-type semiconductor layer utilizes an engineering method to adjust the indium composition of the potential well layer, so that the potential well The bandgap width of the layer is larger than that of other potential well layers. 6. A kind of multiple quantum well structure for photoelectric device according to claim 5, is characterized in that, the potential well layer bandgap width closest to P-type semiconductor layer is greater than the amplitude of other potential well layer bandgap widths at 0.01 Between electron volts and 0.1 electron volts. 7. A kind of multiple quantum well structure for optoelectronic device according to claim 1, it is characterized in that, the potential well layer closest to the P-type semiconductor layer utilizes engineering mode to adjust the potential well layer thickness, so that the potential well layer Thickness is smaller than other potential well layers. 8. A kind of multiple quantum well structure for optoelectronic devices according to claim 7, characterized in that the thickness of the potential well layer closest to the P-type semiconductor layer is less than the amplitude of other potential well layer thicknesses in the range of 0.05 nanometers to 0.5 between nanometers.