Optical device performance improvement method, semiconductor optical device and electronic equipment

Abstract

The embodiments of the present invention provide a method for improving the performance of optical devices, semiconductor optical devices and electronic equipment, and relate to the field of semiconductor optoelectronic technology. The present invention determines the spontaneous polarization intensity of the first compound, the bending parameter of the second compound and the piezoelectric polarization intensity of the material surface where the quantum well is located based on the quantum well's own parameters by constructing a correspondence between the external electric field intensity of the quantum well and the total polarization intensity of the material surface where the quantum well is located. Then, the total spontaneous polarization intensity of the material surface where the quantum well is located is determined based on the piezoelectric polarization intensity and the total polarization intensity. Finally, the material components of the quantum well are determined based on the total spontaneous polarization intensity, the spontaneous polarization intensity of the first compound and the bending parameter of the second compound, so that the polarization electrostatic field intensity of the quantum well is opposite in direction to the external electric field intensity and has the same value. The present invention has the advantage of improving the quantum efficiency and luminous efficiency of AlGaN-based semiconductor ultraviolet devices.

Description

Technical Field

[0001] The present invention relates to the field of semiconductor optoelectronic technology, and in particular to a method for improving the performance of an optical device, a semiconductor optical device, and an electronic device. Background Art

[0002] In recent years, AlGaN-based deep ultraviolet LEDs have the advantages of being environmentally friendly, mercury-free, sterilizable, and having high modulation frequency. They have important commercial application value in the fields of ultraviolet curing, air and water purification, biomedicine, high-density storage, and secure and confidential communications. However, compared with the more mature blue light LEDs, deep ultraviolet LEDs still exhibit lower external quantum efficiency. The key reason for their low efficiency is the low internal quantum efficiency. At present, improving the internal quantum efficiency is closely related to the polarization electric field in addition to the crystal quality of the material growth. Theoretical calculations and experimental measurements show that the polarization electric field of the III-nitride heterojunction is as high as MV / cm, and the interface polarization bound charge is as high as 10 13 cm -1 Compared with the more mature blue light LED, deep ultraviolet LED still shows lower external quantum efficiency. The key reason affecting its low efficiency is the low internal quantum efficiency.

[0003] Improving internal quantum efficiency is not only related to the quality of the crystals grown in the material, but also closely related to the polarization electric field. The polarization electric field affects internal quantum efficiency in two ways: First, due to the different material compositions of the quantum wells / quantum barriers, for example, the different Al material compositions in AlGaN materials, a strong polarization effect (including spontaneous polarization and piezoelectric polarization) will occur. This polarization effect will cause polarized charges to be generated at the quantum well interface, forming a polarized built-in electric field, which in turn causes the energy bands in the quantum well to bend, resulting in spatial separation of electrons and holes injected into the quantum well, reducing the overlap rate of carrier wave functions in the quantum well. This will also reduce the radiative recombination efficiency in the quantum well. At the same time, the band tilt will lead to an excessively high localized carrier state density, thereby increasing the Auger recombination efficiency. Second, the band tilt caused by the polarization effect will also weaken the carrier confinement ability, thereby causing electron leakage and reducing the carrier injection ability.

[0004] Therefore, how to completely avoid or eliminate the negative impact of polarization at the material interface can effectively improve the quantum efficiency and luminous efficiency of ultraviolet semiconductor optical devices. Summary of the Invention

[0005] The present invention provides a method for improving the performance of optical devices, a semiconductor optical device, and an electronic device. This method establishes a corresponding relationship between an externally applied electric field and a built-in electric field generated by reverse polarization in an AlGaN-based deep ultraviolet semiconductor ultraviolet device. This method then precisely regulates the components within the quantum wells in the active region to achieve band flattening, reduce the localized carrier density in the active region, and lower the Auger recombination efficiency. Simultaneously, this method reduces carrier leakage caused by band tilting, improves injection efficiency, and subsequently increases the spatial wave function overlap between electrons and holes, thereby improving the quantum efficiency and luminous efficiency of the AlGaN-based semiconductor ultraviolet device.

[0006] The embodiments of the present invention can be implemented as follows:

[0007] In a first aspect, the present invention provides a method for improving the performance of an optical device, wherein the semiconductor optical device includes a light-emitting active region; the light-emitting active region includes a plurality of quantum barriers and a plurality of quantum wells, wherein the quantum barriers or quantum wells are composed of a Group III element and other elements; the method for improving the performance of the optical device comprises the following steps:

[0008] Obtaining the external electric field strength and intrinsic parameters of the quantum well; wherein the intrinsic parameters include thickness parameters and material parameters;

[0009] Determining a first compound and a second compound in the quantum well based on the material parameters, and determining the spontaneous polarization intensity of the first compound and the bending parameter of the second compound; wherein the first compound is a compound composed of the Group III element and any other element; and the second compound is a compound composed of the Group III element and any other two elements;

[0010] Determining the total polarization intensity of the material surface where the quantum well is located according to the external electric field strength and the thickness parameter;

[0011] Determining the piezoelectric polarization intensity of the material surface where the quantum well is located based on the material parameters; and determining the total spontaneous polarization intensity of the material surface where the quantum well is located based on the piezoelectric polarization intensity and the total polarization intensity;

[0012] The material components of the quantum well are determined according to the total spontaneous polarization intensity, the spontaneous polarization intensity of the first compound, and the bending parameter of the second compound, so that the polarization electrostatic field intensity of the quantum well is opposite in direction to the external electric field intensity and has the same value.

[0013] Furthermore, the step of determining the total polarization intensity of the material surface where the quantum well is located based on the applied electric field strength and the thickness parameter includes:

[0014] Determining the polarization electrostatic field strength of the material surface where the quantum well is located based on the externally applied electric field strength, wherein the value of the polarization electric field strength is the same as the value of the externally applied electric field strength;

[0015] The total polarization intensity of the material surface is determined according to the polarization electrostatic field intensity and the thickness of the quantum well.

[0016] Furthermore, the value of the total polarization intensity satisfies the formula:

[0017] E=P / d

[0018] Wherein, E is the polarization electrostatic field intensity; P is the total polarization intensity; and d is the thickness of the quantum well.

[0019] Furthermore, the material parameters also include the weighted piezoelectric coefficient of the material in the quantum well, the weighted elastic coefficient of the material, and the strain of the plane where the light-emitting active area is located; the value of the piezoelectric polarization intensity satisfies the formula:

[0020]

[0021] Among them, P pz is the piezoelectric polarization intensity of the quantum well; e 31 , e 33 is the material weighted piezoelectric coefficient, C 13 , C 33 is the weighted elastic coefficient of the material, and ε is the strain on the plane where the light-emitting active area is located.

[0022] Furthermore, when the light emitting active region is grown on an AlGaN substrate, the strain value of the plane where the light emitting active region is located satisfies the formula:

[0023]

[0024] Among them, α AlGaN is the lattice constant in the plane of the electron injection layer on the AlGaN substrate; α (x) is the lattice constant of the plane where the light-emitting active area is located in the relaxed state.

[0025] Furthermore, the value of the total spontaneous polarization intensity satisfies the formula:

[0026]

[0027] in, is the total polarization intensity; is the total spontaneous polarization intensity of the quantum well; is the piezoelectric polarization strength of the quantum well.

[0028] Furthermore, when the quantum well includes aluminum indium gallium nitride, the steps of determining the first compound and the second compound in the quantum well according to the material parameters, and determining the spontaneous polarization intensity of the first compound and the bending parameter of the second compound include:

[0029] When the quantum well comprises aluminum indium gallium nitride, the first compound comprises: AlN, InN and GaN; the second compound comprises: AlGaN, InGaN and AlInN;

[0030] The spontaneous polarization strengths of the AlN, the InN, and the GaN are determined respectively; and the bending parameters of the aluminum gallium nitride, the AlGaN, the InGaN, and the AlInN are determined respectively.

[0031] Furthermore, the material components of the quantum well are determined based on the total spontaneous polarization intensity, the spontaneous polarization intensity of the first compound, and the bending parameter of the second compound, wherein the values ​​of the material components satisfy the formula:

[0032]

[0033] in, is the total spontaneous polarization intensity of AlInGaN material; is the spontaneous polarization intensity of InN material; is the spontaneous polarization intensity of AlN; is the spontaneous polarization intensity of GaN material; b AlGaN 、b InGaN and b AllnN are the bending parameters of AlGaN, InGaN, and AlInN, respectively; x and y are the Al component and In component in AlInGaN, respectively.

[0034] In a second aspect, the present invention further provides a semiconductor optical device, wherein the epitaxial structure of the semiconductor optical device comprises an AlN buffer layer, an n-type AlGaN layer, a light-emitting active region, a p-type AlGaN electron blocking layer, a p-type AlGaN layer, and a p-type GaN contact layer arranged in sequence on a substrate;

[0035] Wherein, the material composition of the quantum well in the light-emitting active region is determined by the optical device performance improvement method described in any one of the first aspects above.

[0036] In a third aspect, the present invention further provides an electronic device comprising: a processor and a memory, wherein the memory is used to store one or more programs; when the one or more programs are executed by the processor, the method for improving the performance of an optical device as described in any one of the first aspects above is implemented.

[0037] The beneficial effects of the embodiments of the present invention include, for example:

[0038] The present invention obtains the external electric field strength and the parameters of the quantum well, and determines the first compound and the second compound in the quantum well based on the material parameters, and simultaneously determines the spontaneous polarization strength of the first compound and the bending parameters of the second compound. Then, the total polarization strength of the material surface where the quantum well is located is determined based on the external electric field strength and the thickness parameters. After determining the piezoelectric polarization strength of the material surface where the quantum well is located, the total spontaneous polarization strength of the material surface where the quantum well is located is determined based on the total polarization strength. Finally, the material components of the quantum well are determined based on the total spontaneous polarization strength, the spontaneous polarization strength of the first compound, and the bending parameters of the second compound, so that the polarization electrostatic field strength of the quantum well is opposite in direction to the external electric field strength and has the same value. The present invention establishes a corresponding relationship between the external electric field and the built-in electric field generated by reverse polarization in an AlGaN-based deep ultraviolet semiconductor ultraviolet device, and then accurately controls the components in the quantum well in the active region to achieve band flattening, reduce the local carrier density in the active region, and reduce the Auger recombination efficiency. At the same time, the leakage of carriers caused by band tilt is reduced, the injection efficiency is improved, and the spatial wave function overlap rate of electrons and holes is increased, thereby improving the quantum efficiency and luminescence efficiency of AlGaN-based semiconductor ultraviolet devices. BRIEF DESCRIPTION OF THE DRAWINGS

[0039] In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the following briefly introduces the drawings required for use in the embodiments. It should be understood that the following drawings only illustrate certain embodiments of the present invention and therefore should not be regarded as limiting the scope. For ordinary technicians in this field, other relevant drawings can be obtained based on these drawings without paying any creative work.

[0040] Figure 1 A device structure diagram of a semiconductor optical device provided by an embodiment of the present invention;

[0041] Figure 2 A flowchart of a method for improving optical device performance provided by an embodiment of the present invention;

[0042] Figure 3 A step-by-step flow chart of S3 is provided for an embodiment of the present invention;

[0043] Icon: 100 - semiconductor optical device; 1 - substrate; 2 - AlN buffer layer; 3 - n-type AlGaN layer; 4 - light-emitting active region; 5 - p-type AlGaN electron blocking layer; 6 - p-type AlGaN layer; 7 - p-type GaN contact layer. DETAILED DESCRIPTION

[0044] To make the objectives, technical solutions, and advantages of the embodiments of the present invention more clear, the technical solutions of the embodiments of the present invention will be clearly and completely described below in conjunction with the accompanying drawings of the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Generally, the components of the embodiments of the present invention described and shown in the drawings herein can be arranged and designed in various different configurations.

[0045] Therefore, the following detailed description of the embodiments of the present invention provided in the accompanying drawings is not intended to limit the scope of the invention as claimed, but rather merely represents selected embodiments of the present invention. All other embodiments derived by persons of ordinary skill in the art based on the embodiments of the present invention without creative effort shall fall within the scope of protection of the present invention.

[0046] It should be noted that similar reference numerals and letters denote similar items in the following drawings, and therefore, once an item is defined in one drawing, it does not require further definition or explanation in subsequent drawings.

[0047] In the description of the present invention, it should be noted that if the terms "upper", "lower", "inside", "outside", etc. appear, the orientation or position relationship indicated is based on the orientation or position relationship shown in the accompanying drawings, or is the orientation or position relationship in which the product of the invention is usually placed when in use. It is only for the convenience of describing the present invention and simplifying the description, and does not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation. Therefore, it should not be understood as a limitation on the present invention.

[0048] In addition, the terms "first", "second", etc., if used, are merely used to distinguish and describe, and should not be understood as indicating or implying relative importance.

[0049] It should be noted that, in the absence of conflict, the features in the embodiments of the present invention may be combined with each other.

[0050] As described in the background, compared to more mature blue LEDs, deep ultraviolet LEDs still exhibit lower external quantum efficiency. The key factor affecting their low efficiency is their low internal quantum efficiency. Currently, improving internal quantum efficiency is not only related to the quality of the crystals grown in the material, but also closely related to the polarization field. This polarization field affects internal quantum efficiency in two ways. First, due to the different Al compositions in AlGaN materials, the strong polarization effect (including spontaneous polarization and piezoelectric polarization) in AlGaN materials causes polarized charges to be generated at the quantum well interface, forming a polarized built-in electric field. This in turn bends the energy bands in the quantum wells, leading to spatial separation of electrons and holes injected into the quantum wells and reducing the overlap rate of carrier wave functions within the quantum wells. This also reduces the radiative recombination efficiency in the quantum wells. Furthermore, band tilting can lead to excessively high localized carrier state density, thereby increasing the Auger recombination efficiency. Second, the band tilt caused by the polarization effect can weaken the carrier confinement ability, leading to electron leakage and reduced carrier injection capability.

[0051] Therefore, the negative impact of polarization electric fields can seriously affect the performance of optoelectronic devices. Therefore, how to completely avoid or eliminate the negative impact of polarization at the material interface can effectively improve the quantum efficiency and luminous efficiency of ultraviolet semiconductor optical devices.

[0052] Based on this, embodiments of the present invention provide a method for improving the performance of optical devices, a semiconductor optical device, and an electronic device. By utilizing the superposition of the polarization built-in electric field generated by polarization at the material interface and the external electric field, the energy band tilt caused by the polarization built-in electric field is weakened or completely eliminated, the wave function overlap rate of carriers in the quantum well is increased, and the radiative recombination efficiency is improved. At the same time, the local carrier density in the active region is reduced, reducing the Auger recombination efficiency. By flattening the energy band, the carrier leakage capacity is greatly reduced, and the injection efficiency is improved. The internal quantum efficiency is greatly improved.

[0053] First, please refer to Figure 1 An embodiment of the present invention provides a semiconductor optical device 100, wherein the epitaxial structure of the semiconductor optical device 100 includes an AlN buffer layer 2, an n-type AlGaN layer 3, a light-emitting active region 4, a p-type AlGaN electron blocking layer 5, a p-type AlGaN layer 6, and a p-type GaN contact layer 7, sequentially disposed on a substrate 1. The light-emitting active region 4 includes multiple quantum barriers and multiple quantum wells, each composed of a Group III element and other elements. The material composition of the quantum wells in the light-emitting active region 4 is determined using a method for improving optical device performance.

[0054] In this embodiment, the substrate 1 of the semiconductor optical device may include various semiconductor substrates such as sapphire, SiC, Si, AlN, etc. wherein quantum wells and quantum barriers alternately form a light-emitting active region. x1Ga 1-x1 N / Al x In y Ga 1-x-y When the light-emitting active region is GaN, in the light-emitting active region, 0 < x1 ≤ 1, 0 < x < 1, 0 < y < 1, and the quantum barrier AlGaN in the light-emitting active region x1 Ga 1-x1 The minimum bandgap Eg of N is greater than that of the quantum well AlInGaN. Among them, the thickness of the quantum barrier AlGaN x In y Ga 1-x-y The minimum bandgap Eg of N, where the thickness of the quantum barrier AlGaN x1 Ga 1-x1 N is 5 - 50 nm, and the thickness of the quantum well AlInGaN x In y Ga 1-x-y N is 1 - 20 nm.

[0055] Please refer to Figure 2 , an embodiment of the present invention provides a method for improving the performance of an optical device, including the following steps:[[ID=No. 34]] [[ID=No. 35]]

[0056] S1. Obtain the applied electric field strength and its own parameters of the quantum well; among them, the own parameters include thickness parameters and material parameters;

[0057] S2. Determine the first compound and the second compound in the quantum well according to the material parameters, and determine the spontaneous polarization intensity of the first compound and the bending parameter of the second compound; among them, the first compound is a compound composed of a group III element and any other element; the second compound is a compound composed of a group III element and any two other elements;

[0058] S3. Determine the total polarization intensity of the material surface where the quantum well is located according to the applied electric field strength and the thickness parameters;

[0059] S4. Determine the piezoelectric polarization intensity of the material surface where the quantum well is located according to the material parameters; and determine the total spontaneous polarization intensity of the material surface where the quantum well is located according to the piezoelectric polarization intensity and the total polarization intensity; <​​​The embodiments of the present invention construct an external electric field of a semiconductor optical device, especially the external electric field strength of the light-emitting active region, and a corresponding relationship between the polarized built-in electric field generated by polarization at the material interface, so as to improve the quantum efficiency and luminous efficiency of the AlGaN-based semiconductor ultraviolet device, wherein the polarized built-in electric field is the polarized electrostatic field at the interface where the quantum well is located as described in the present invention. In the embodiment of the present invention, the polarized electrostatic field strength of the quantum well is opposite in direction to the external electric field strength and has the same value. The present invention constructs a superposition relationship between the external electric field and the polarized electrostatic field at the interface where the quantum well is located, which is reflected in the present embodiment as follows: making the polarized electrostatic field strength of the quantum well opposite in direction to the external electric field strength and having the same value. Based on this, the present invention can weaken or completely eliminate the band tilt caused by the polarized built-in electric field, and improve the quantum efficiency and luminous efficiency of the AlGaN-based semiconductor ultraviolet device.

[0062] The present invention also provides a method for improving optical device performance based on embodiments of the present invention when determining the applied electric field, epitaxial structure, and quantum well structure of a semiconductor optical device. By calculating the built-in electric field strength that matches the applied electric field, the material composition of the quantum well can be inferred, thereby guiding epitaxial growth to produce a high-efficiency epitaxial material.

[0063] In this embodiment, the step of determining the applied electric field strength of the quantum well in S1 may include: determining the average current density of the semiconductor optical device under current electrical injection based on the dimensions of the semiconductor optical device and the injection current of the n-type AlGaN layer. Then, determining the voltage corresponding to the average current density based on the current current-voltage characteristic curve of the semiconductor optical device. Finally, determining the applied electric field value of the semiconductor optical device, particularly the electric field strength of the active region quantum well, based on this voltage. In one conceivable embodiment, for example, the current electrical injection is 150 mA and the device dimensions are 20 x 20 mil. Based on the above parameters, the average current density under current electrical injection can be determined to be 60 A / cm. Furthermore, the applied electric field strength applied to the active region quantum well can be estimated to be approximately 1E4 V / cm to 1E5 V / cm. To weaken or completely eliminate band tilting caused by the polarization internal electric field, the polarization electrostatic field strength of the quantum well is opposite in direction to the applied electric field strength and has the same magnitude. After establishing this equation, the material composition of the quantum well can be determined one by one according to the above steps. Thereby obtaining a deep ultraviolet solid-state light source with high light efficiency.

[0064] The present invention does not limit the method for obtaining the electric field strength of the quantum well in the light-emitting active region. It should be noted that the material composition of the quantum well in the present invention can make the polarization electrostatic field at the material interface where the quantum well is located opposite to the direction of the external electric field where the quantum well is located. For example, the quantum well can be composed of aluminum indium gallium nitride (AINGaN). However, the material composition includes but is not limited to AINGaN, as long as it can make the polarization electrostatic field at the material interface where the quantum well is located opposite to the direction of the external electric field where the quantum well is located.

[0065] In this embodiment, the material parameters include but are not limited to the material weighted piezoelectric coefficient, the material weighted elastic coefficient, the spontaneous polarization intensity between the compound composed of the group III element and any other element, and the bending parameter between the compound composed of the group III element and any other two elements.

[0066] In this embodiment, when the quantum well may be aluminum indium gallium nitride, the steps of determining the first compound and the second compound in the quantum well based on the material parameters, and determining the spontaneous polarization intensity of the first compound and the bending parameter of the second compound include:

[0067] When the quantum well comprises aluminum indium gallium nitride, the first compound comprises: AlN, InN and GaN; the second compound comprises: AlGaN, InGaN and AlInN;

[0068] The spontaneous polarization strengths of AlN, InN, and GaN; and the bending parameters of AlGaN, InGaN, and AlInN are determined respectively.

[0069] Please refer to Table 1, which shows the basic parameters of Group III nitrides.

[0070] AlN GaN InN unit Bandgap 6.2 3.4 0.7 eV Lattice constant (a) 0.3112 0.3189 0.3533 nm Lattice constant (c) 0.4982 0.5186 0.5693 nm Coefficient of thermal expansion 4.2 5.59 ～4.0 <![CDATA[10 -6 K -1 ]]> Coefficient of thermal expansion 5.3 3.17 ～3.0 <![CDATA[10 -6 K -1 ]]> Thermal conductivity 2 1.3 0.8 <![CDATA[W cm -1 K -1 ]]> Piezoelectric constant -0.48 -0.33 -0.57 <![CDATA[C / m 2 ]]> Piezoelectric constant ( 1.55 0.65 0.97 <![CDATA[C / m 2 ]]> Elastic modulus 108 103 92 GPa Elastic modulus 473 405 224 GPa Spontaneous polarization intensity -0.081 -0.029 -0.032 <![CDATA[C / m 2 ]]> Radiation Recombination Coefficient 1.8 4.7 5.2 <![CDATA[10 -11 cm 3 / s]]> density 3.23 6.15 6.81 <![CDATA[g cm -3 ]]> Electron effective mass 0.48 0.2 0.11 <![CDATA[m0]]> Electron saturation velocity (Ve) 1.4 2.5 2.5 <![CDATA[10 7 cm s -1 ]]>

[0071] In this embodiment, b(AlGaN)=0.7, b(InGaN)=1.4, and b(AlInN)=2.5.

[0072] Based on this, in this embodiment, the material components of the quantum well can be determined based on the total spontaneous polarization intensity, the spontaneous polarization intensity of the first compound, and the bending parameter of the second compound, wherein the value of each material component satisfies the formula:

[0073]

[0074] in, is the total spontaneous polarization intensity of AlInGaN material; is the spontaneous polarization intensity of InN material; is the spontaneous polarization intensity of AlN; is the spontaneous polarization intensity of GaN material; b AlGaN 、b InGaN and b AllnNThe bending parameters of AlGaN, InGaN, and AlInN, respectively; x and y are the Al component and In component in AlInGaN, respectively. In this embodiment, since the material spontaneous polarization intensities of InN, AlN, GaN, and the bending parameters of AlGaN, InGaN, and AlInN are all known quantities, the Al component and In component in AlInGaN can be determined based on the total material spontaneous polarization intensity of AlInGaN.

[0075] Among them, the total polarization intensity of the material surface where the quantum well is located is composed of the total material spontaneous polarization intensity of AlInGaN and the piezoelectric polarization intensity of the material surface where the quantum well is located. That is, the value of the total spontaneous polarization intensity satisfies the formula:

[0076]

[0077] Among them, is the total polarization intensity; is the total spontaneous polarization intensity of the quantum well; is the piezoelectric polarization intensity of the quantum well.

[0078] Then in this embodiment, the total material spontaneous polarization intensity of AlInGaN can be deduced by determining the total polarization intensity of the material surface where the quantum well is located and the piezoelectric polarization intensity of the material surface where the quantum well is located so as to determine the Al component and In component in AlInGaN. And based on this embodiment, when the quantum well is Al x In y Ga 1-x-y N, it also satisfies 0 < x < 1, 0 < y < 1, and then the optimal Al component and In component are determined.

[0079] In this embodiment, please refer to Figure 3 , the steps of determining the total polarization intensity of the material surface where the quantum well is located according to the applied electric field strength and thickness parameter include:

[0080] S31. Determine the polarization electrostatic field intensity of the material surface where the quantum well is located according to the applied electric field strength. Among them, the value of the polarization electric field intensity is the same as the value of the applied electric field strength;

[0081] S32. Determine the total polarization intensity of the material surface where the quantum well is located according to the polarization electrostatic field intensity and the thickness of the quantum well. Among them, in this embodiment, the value of the total polarization intensity satisfies the formula:

[0082] E = P / d

[0083] Among them, E is the polarization electrostatic field intensity; P is the total polarization intensity; d is the thickness of the quantum well.

[0084] The piezoelectric polarization strength of the material surface where the quantum well is located can be determined by the material parameters, wherein the material parameters that determine the piezoelectric polarization strength of the material surface where the quantum well is located include the weighted piezoelectric coefficient of the material in the quantum well, the weighted elastic coefficient of the material, and the strain of the plane where the light-emitting active area is located; these material parameters can all be obtained from Table 1.

[0085] Based on the above material parameters, the value of the piezoelectric polarization strength satisfies the formula:

[0086]

[0087] Among them, P pz is the piezoelectric polarization strength of the quantum well; e 31 , e 33 is the material weighted piezoelectric coefficient, C 13 , C 33 is the weighted elastic coefficient of the material, and ε is the strain on the plane where the light-emitting active area is located.

[0088] In this embodiment, when the light emitting active region is grown on an AlGaN substrate, the strain value of the plane where the light emitting active region is located satisfies the formula:

[0089]

[0090] Among them, α AlGaN is the lattice constant of the electron injection layer (n-AlGaN) on the AlGaN substrate in the plane; α (x) is the lattice constant of the plane where the light-emitting active area is located in the relaxed state.

[0091] In this embodiment, when the n-AlGaN electron injection layer changes, the variable correspondence relationship can be used to calculate the lattice constant of the epitaxial layer in a relaxed state, and thus the strain in the plane where the light-emitting active region is located. The present invention does not limit the method for obtaining this strain. In the present invention, the strain can be determined by the lattice constant in the plane where the electron injection layer (n-AlGaN) on the AlGaN substrate is located and the lattice constant in the plane where the light-emitting active region is located in a relaxed state.

[0092] Since the present invention makes the polarization electrostatic field intensity of the quantum well opposite to the external electric field intensity and the same in value, the polarization electrostatic field intensity of the quantum well can be determined by the value of the external electric field intensity. The polarization electrostatic field intensity is composed of the total spontaneous polarization intensity and the piezoelectric polarization intensity. Among them, the piezoelectric polarization intensity can be determined after confirming the material composition in the quantum well. Therefore, the total spontaneous polarization intensity of the quantum well can be determined based on the polarization electrostatic field intensity and the piezoelectric polarization intensity. Finally, the various material components of the quantum well are determined based on the total spontaneous polarization intensity of the quantum well, the spontaneous polarization intensity of the first compound in the quantum well and the bending parameter of the second compound. Based on this, the present invention can determine the values ​​of the Al component and the In component in AlInGaN, and after considering the difficulty of the actual epitaxial growth parameters, accurately determine the appropriate InAl content, and realize the preparation of a high-efficiency and high-quality deep ultraviolet solid-state light source.

[0093] In summary, the present invention provides a method for improving the performance of optical devices. The method can obtain the external electric field strength and the parameters of the quantum well, and determine the first compound and the second compound in the quantum well based on the material parameters, and simultaneously determine the spontaneous polarization intensity of the first compound and the bending parameter of the second compound. Then, the total polarization intensity of the material surface where the quantum well is located is determined based on the external electric field strength and the thickness parameters. After determining the piezoelectric polarization intensity of the material surface where the quantum well is located, the total spontaneous polarization intensity of the material surface where the quantum well is located is determined based on the total polarization intensity. Finally, the material components of the quantum well are determined based on the total spontaneous polarization intensity, the spontaneous polarization intensity of the first compound, and the bending parameter of the second compound, so that the polarization electrostatic field intensity of the quantum well is opposite in direction to the external electric field intensity and has the same value. The present invention establishes a corresponding relationship between the external electric field and the built-in electric field generated by the reverse polarization in an AlGaN-based deep ultraviolet semiconductor ultraviolet device, and then accurately controls the components in the quantum well in the active region to achieve band flattening, reduce the local carrier density in the active region, and reduce the Auger recombination efficiency. At the same time, the leakage of carriers caused by band tilt is reduced, the injection efficiency is improved, and the spatial wave function overlap rate of electrons and holes is increased, thereby improving the quantum efficiency and luminescence efficiency of AlGaN-based semiconductor ultraviolet devices.

[0094] On the other hand, the present invention can calculate the matching built-in electric field strength by mastering the epitaxial structure, quantum well structure and the known external electric field strength, and then deduce the components of the quantum well, thereby accurately guiding the epitaxial growth to obtain a high-efficiency deep ultraviolet solid-state light source.

[0095] In a third aspect, the present invention further provides an electronic device comprising: a processor and a memory, the memory being used to store one or more programs; when the one or more programs are executed by the processor, any of the above-mentioned methods for improving the performance of optical devices is implemented.

[0096] The processor and memory in this electronic device possess all the technical features and beneficial effects of the method for improving the performance of optical devices. For example, a corresponding relationship between an external electric field and a built-in electric field generated by reverse polarization can be established in an AlGaN-based deep ultraviolet semiconductor ultraviolet device, thereby precisely controlling the components within the quantum wells in the active region to achieve band flattening, reduce the local carrier density in the active region, and lower the Auger recombination efficiency. At the same time, the leakage of carriers caused by band tilt is reduced, the injection efficiency is improved, and the spatial wave function overlap rate of electrons and holes is increased, thereby improving the quantum efficiency and luminous efficiency of the AlGaN-based semiconductor ultraviolet device.

[0097] The above description is merely a specific embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any changes or substitutions that can be easily conceived by a person skilled in the art within the technical scope disclosed in the present invention should be included in the scope of protection of the present invention. Therefore, the scope of protection of the present invention should be based on the scope of protection of the claims.

Claims

1. A method for improving the performance of an optical device, characterized in that: The optical device includes a light-emitting active region; the light-emitting active region includes a plurality of quantum barriers and a plurality of quantum wells, and the quantum barriers or quantum wells are composed of Group III elements and other elements; the optical device performance improvement method includes the following steps: Obtaining the external electric field strength and intrinsic parameters of the quantum well; wherein the intrinsic parameters include thickness parameters and material parameters; the material parameters include the weighted piezoelectric coefficient of the material in the quantum well, the weighted elastic coefficient of the material, and the strain of the plane where the light-emitting active area is located; Determining a first compound and a second compound in the quantum well based on the material parameters, and determining the spontaneous polarization intensity of the first compound and the bending parameter of the second compound; wherein the first compound is a compound composed of the Group III element and any other element; and the second compound is a compound composed of the Group III element and any other two elements; Determining the total polarization intensity of the material surface where the quantum well is located according to the external electric field strength and the thickness parameter; Determining the piezoelectric polarization intensity of the material surface where the quantum well is located based on the material parameters; and determining the total spontaneous polarization intensity of the material surface where the quantum well is located based on the piezoelectric polarization intensity and the total polarization intensity; The material components of the quantum well are determined according to the total spontaneous polarization intensity, the spontaneous polarization intensity of the first compound, and the bending parameter of the second compound, so that the polarization electrostatic field intensity of the quantum well is opposite in direction to the external electric field intensity and has the same value.

2. The method for improving optical device performance according to claim 1, wherein: The step of determining the total polarization intensity of the material surface where the quantum well is located based on the external electric field intensity and the thickness parameter comprises: Determining the polarization electrostatic field strength of the material surface where the quantum well is located based on the externally applied electric field strength, wherein the value of the polarization electrostatic field strength is the same as the value of the externally applied electric field strength; The total polarization intensity of the material surface is determined according to the polarization electrostatic field intensity and the thickness of the quantum well.

3. The method for improving optical device performance according to claim 2, wherein: The value of the total polarization intensity satisfies the formula: E=P / d Wherein, E is the polarization electrostatic field intensity; P is the total polarization intensity; and d is the thickness of the quantum well.

4. The method for improving optical device performance according to claim 1, wherein: The material parameters also include the weighted piezoelectric coefficient of the material in the quantum well, the weighted elastic coefficient of the material, and the strain of the plane where the light-emitting active area is located; the value of the piezoelectric polarization intensity satisfies the formula: ； in, P pz is the piezoelectric polarization intensity of the quantum well; e 31 , e 33 is the material weighted piezoelectric coefficient, C 13 , C 33 is the weighted elastic coefficient of the material, ε It is the strain on the plane where the light-emitting active area is located.

5. The method for improving optical device performance according to claim 4, wherein: When the light emitting active region is grown on an AlGaN substrate, the strain value of the plane where the light emitting active region is located satisfies the formula: in, is the lattice constant in the plane where the electron injection layer on the AlGaN substrate is located; is the lattice constant of the plane where the light-emitting active area is located in the relaxed state.

6. The method for improving optical device performance according to claim 1, wherein: The value of the total spontaneous polarization intensity satisfies the formula: in, is the total polarization intensity; is the total spontaneous polarization intensity of the quantum well; is the piezoelectric polarization strength of the quantum well.

7. The method for improving optical device performance according to claim 1, wherein: When the quantum well includes aluminum indium gallium nitride, the steps of determining a first compound and a second compound in the quantum well according to the material parameters, and determining a spontaneous polarization intensity of the first compound and a bending parameter of the second compound include: When the quantum well comprises aluminum indium gallium nitride, the first compound comprises: AlN, InN and GaN; the second compound comprises: AlGaN, InGaN and AlInN; The spontaneous polarization intensities of the AlN, the InN, and the GaN are determined; and the bending parameters of the AlGaN, the InGaN, and the AlInN are determined respectively.

8. The method for improving optical device performance according to claim 7, wherein: The material components of the quantum well are determined based on the total spontaneous polarization intensity, the spontaneous polarization intensity of the first compound, and the bending parameter of the second compound, wherein the values ​​of the material components satisfy the formula: in, is the total spontaneous polarization intensity of AlInGaN material; is the spontaneous polarization intensity of InN material; is the spontaneous polarization intensity of AlN; is the spontaneous polarization intensity of GaN material; 、 as well as These are the bending parameters of AlGaN, InGaN, and AlInN, respectively; x , y They are the Al component and In component in AlInGaN respectively.

9. A semiconductor optical device, characterized in that: The epitaxial structure of the semiconductor optical device comprises an AlN buffer layer, an n-type AlGaN layer, a light-emitting active region, a p-type AlGaN electron blocking layer, a p-type AlGaN layer and a p-type GaN contact layer arranged in sequence on a substrate; Wherein, the material composition of the quantum well in the light-emitting active region is determined by the method for improving the performance of an optical device according to any one of claims 1 to 8.

10. An electronic device, characterized in that: include: a processor and a memory, the memory being configured to store one or more programs; When the one or more programs are executed by the processor, the method for improving the performance of an optical device according to any one of claims 1 to 8 is implemented.

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