A method based on polarization-enhanced carrier separation efficiency of Ga2O3 / WS2

Abstract

The application discloses a method based on polarization enhanced Ga2O3 / WS2 carrier separation efficiency, and belongs to the technical field of semiconductor photocatalysis and photovoltaic equipment, and comprises the following steps: constructing a Ga2O3 / WS2 ferroelectric heterojunction atomic structure model with different polarization directions, setting a vacuum layer greater than 15 angstroms along the normal direction, and performing energy minimization on the atomic structure model to obtain a stable crystal structure; based on the stable crystal structure obtained by S1, the projected band structure, the energy band alignment mode, the electrostatic potential function, the work function, the differential charge density and the Bader charge are calculated respectively. The application can realize the simulation of the electronic structure, the interface charge distribution and the carrier interlayer transfer dynamics of Ga2O3 / WS2 heterojunctions with different polarization directions, can accurately identify the energy band alignment type, obtain the electron and hole transfer time, the carrier recombination lifetime and the coupling phonon characteristics, and thus can screen out heterostructure types with high carrier separation efficiency.

Description

Technical Field

[0001] This invention relates to the field of semiconductor photocatalysis and photovoltaic equipment technology, and in particular to a method based on polarization-enhanced Ga2O3 / WS2 carrier separation efficiency. Background Technology

[0002] Two-dimensional ferroelectric semiconductor materials possess reversible polarization properties, showing broad application prospects in optoelectronic devices, photocatalysis, and non-volatile memories. Type-II heterojunctions, due to their band alignment enabling spatial separation of photogenerated electrons and holes, are key structures for improving the performance of optoelectronic devices. Ferroelectric Type-II heterojunctions, formed by combining ferroelectric and non-ferroelectric elements, are expected to further enhance interface charge separation, thereby improving carrier separation efficiency and photoelectric conversion efficiency. However, systematic and in-depth research on how polarization enhances photogenerated carrier separation efficiency is still lacking. Ga2O3 / WS2 heterojunctions, as high-performance ferroelectric heterojunctions, exhibit good thermal stability and optical properties, but the formation, transfer, and recombination mechanisms of photogenerated carriers at their heterojunction remain to be elucidated. Currently, there is a lack of exploration into the microscopic mechanisms of ultrafast charge transfer dynamics of photogenerated carriers in Ga2O3 / WS2 heterojunctions, especially the dynamic control mechanism of polarization on the carrier separation process, which has not yet been reported.

[0003] Therefore, this invention proposes a method based on polarization-enhanced Ga2O3 / WS2 carrier separation efficiency to overcome the shortcomings of the prior art. Summary of the Invention

[0004] The purpose of this invention is to provide a method for enhancing the carrier separation efficiency of Ga2O3 / WS2 based on polarization. This method combines first-principles calculations and non-adiabatic molecular dynamics simulations, aiming to reveal the microscopic mechanism by which polarization reversal regulates the electronic properties and carrier separation efficiency of Ga2O3 / WS2 heterojunctions, and to provide theoretical basis and technical guidance for improving the performance of photocatalysis and optoelectronic devices.

[0005] To achieve the above objectives, the present invention adopts the following technical solution:

[0006] This invention proposes a method for enhancing the carrier separation efficiency of Ga2O3 / WS2 based on polarization, comprising the following steps:

[0007] S1. Construct atomic structure models of Ga2O3 / WS2 ferroelectric heterojunctions with different polarization directions, set a vacuum layer greater than 15 Å along the normal direction, and minimize the energy of the atomic structure models to obtain a stable crystal structure.

[0008] S2. Based on the stable crystal structure obtained in S1, calculate the band structure, band alignment, electrostatic potential function, work function, differential charge density, and Bader charge respectively.

[0009] S3. The atomic structure model of the Ga2O3 / WS2 ferroelectric heterojunction includes two configurations: Ga2O3↓ / WS2 and Ga2O3↑ / WS2. Based on the electrostatic potential function in S2, the polarization direction of the Ga2O3↓ / WS2 configuration is determined to be from the WS2 layer to the Ga2O3 layer, while the polarization direction of the Ga2O3↑ / WS2 configuration is from the Ga2O3 layer to the WS2 layer. The electron transfer direction is determined based on the work function and differential charge density, with electrons transferring from the WS2 layer (lower work function) to the Ga2O3 layer (higher work function). The charge transfer amount is determined based on the Bader charge.

[0010] S4. The relaxation dynamics of carriers in Ga2O3 / WS2 ferroelectric heterojunctions with different polarization directions were simulated using non-adiabatic molecular dynamics methods. The ultrafast electron-hole interlayer transfer time and carrier recombination lifetime were obtained to determine that polarization causes photogenerated carriers to migrate in the opposite polarization direction.

[0011] Preferably, in step S1, the energy minimization setting specifically includes: introducing DFT-D3 van der Waals correction, setting the cutoff energy of the plane wave basis set to 600 eV, and the energy convergence threshold to 10 eV. -6 eV, the interatomic force convergence threshold is 0.01eV / Å, and the reciprocal space K-point grid is set to 9×9×1.

[0012] Preferably, in step S2, when calculating the band structure, the HSE06 hybrid functional and PBE functional are used to calculate the band structure. The band alignment of the Ga2O3 / WS2 ferroelectric heterojunction is determined to be either Type-II or Type-III by projecting the band structure, and its valence band offset and conduction band offset are calculated.

[0013] After applying dipole correction along the normal direction to the Ga2O3 / WS2 ferroelectric heterojunction, the electrostatic potential function and work function of the heterojunction, as well as the Ga2O3 monolayer and WS2 monolayer, are calculated.

[0014] The charge densities of Ga2O3 / WS2, Ga2O3, and WS2 are calculated respectively. The differential charge density is obtained by subtracting the charge densities of Ga2O3 monolayer and WS2 monolayer from the charge density of Ga2O3 / WS2.

[0015] The Bader charge of the Ga2O3↓ / WS2 and Ga2O3↑ / WS2 ferroelectric heterojunctions is calculated separately, and the independent Bader charge information of the Ga2O3 monolayer and WS2 monolayer is extracted to determine the Bader charge amount of the Ga2O3 monolayer and WS2 monolayer that make up the heterojunction.

[0016] Preferably, S4 specifically includes:

[0017] The crystal structure after minimizing the S1 energy is rotated into an orthorhombic unit cell, and the orthorhombic unit cell is expanded into a 3×3×1 orthorhombic supercell;

[0018] A 3×3×1 orthogonal supercell was heated to 300K and reached thermodynamic equilibrium in an NVT ensemble within a time step of 1 fs using a rate adjustment method.

[0019] Molecular dynamics simulations were performed on the orthogonal supercell after thermal equilibrium under the NVE ensemble, generating dynamic trajectories with a 5 ps time step and a 1 fs time step.

[0020] Extract the final 2ps dynamic trajectory to obtain 2000 atomic structures, and construct non-adiabatic molecular dynamics minimum surface jump samples;

[0021] The wave functions and projected energy levels of the 2000 dynamic trajectory samples were obtained for non-adiabatic molecular dynamics calculations, and 500 initial structures were randomly selected from them for minimum surface jump calculations.

[0022] The initial positions of electron and hole energy relaxation are determined based on the time evolution of energy states, causing hot carriers to condense to the band edge positions, and the interlayer transfer time of electrons and holes is obtained; electrons relax from the top of the valence band to the bottom of the conduction band and recombine with holes, thus obtaining the recombination lifetime of the carriers.

[0023] Preferably, it further includes S5, which specifically involves: extracting the 2ps dynamic trajectories of the valence band top and conduction band bottom of the Ga2O3 / WS2 ferroelectric heterojunction with different polarization directions in S4, performing Fourier transforms on the 2ps dynamic trajectories respectively to obtain the characteristic phonon spectrum, determining the characteristic phonon frequency coupled with the electron-phonon in the carrier transfer process, and identifying the phonon mode that dominates the interlayer transfer of carriers.

[0024] The present invention has the following technical effects:

[0025] This invention enables the simulation of the electronic structure, interface charge distribution, carrier relaxation, and interlayer transfer dynamics of Ga2O3 / WS2 heterojunctions with different polarization directions. It can accurately identify band alignment types, obtain electron and hole interlayer transfer times, carrier recombination lifetimes, and coupled phonon characteristics, thereby screening out heterostructures with high carrier separation efficiency and providing theoretical support for photocatalysis and optoelectronic device applications. Attached Figure Description

[0026] Figure 1 This is a projected band structure diagram of the Ga2O3↓ / WS2 and Ga2O3↑ / WS2 heterojunctions in embodiments of the present invention, wherein... Figure 1 (a) Figure 1 (d) in the figure represents the result of the HSE06 functional calculation; Figure 1 (b) Figure 1 (e) in the figure represents the result of the PBE functional calculation; Figure 1 (c) Figure 1 (f) in the equation corresponds to the band alignment method.

[0027] Figure 2 The figures show the electrostatic potential and differential charge density diagrams of Ga2O3↓ / WS2 and Ga2O3↑ / WS2 in embodiments of the present invention, wherein... Figure 2 (a) Figure 2 (b) Figure 2 (c) and Figure 2 In the figure, (d) represents the plane-average electrostatic potential along the z-direction for WS2 monolayer, Ga2O3 monolayer, Ga2O3↓ / WS2, and Ga2O3↑ / WS2, respectively. Figure 2 In the diagram, (e) represents the differential charge density of Ga2O3↓ / WS2, with the yellow area indicating charge accumulation and the cyan area indicating charge consumption. Figure 2 In the diagram, (f) represents the differential charge density of Ga2O3↑ / WS2. The yellow area represents charge accumulation, and the cyan area represents charge consumption. The red arrows indicate the direction of electron transfer and the amount of Bader charge.

[0028] Figure 3 The above are carrier relaxation dynamics diagrams of Ga2O3↓ / WS2 and Ga2O3↑ / WS2 at 300K in embodiments of the present invention. Figure 3 (a) Figure 3 In this context, (d) represents the change of electron energy over time. Figure 3 (b) and (c) in the figure represent the electron and hole transfer processes of Ga2O3↓ / WS2; Figure 3 (e) in the equation represents the electron transfer process of Ga2O3↑ / WS2; Figure 3 (f) in the diagram represents the recombination process of the two carrier configurations.

[0029] Figure 4 This is a diagram illustrating the microscopic mechanism of carrier transfer in an embodiment of the present invention, wherein... Figure 4 (a) Figure 4 (b) represents the average non-adiabatic coupling matrix element; Figure 4 (c) Figure 4 In the spectrum (d), the Fourier transform spectrum is represented by the spectrum (d). Detailed Implementation

[0030] To more clearly illustrate the technical solution and beneficial effects of the present invention, this patent provides a more detailed description in conjunction with specific implementation examples; it is worth noting that the specific implementation examples are only used to explain the present invention, but are not limited to the present invention.

[0031] Model building and parameter settings were performed using the VASP 5.4.4 software package.

[0032] (1) Construct atomic structure models of Ga2O3 / WS2 ferroelectric heterojunctions with different polarization directions. To study the surface and interface properties of Ga2O3 / WS2 ferroelectric heterojunctions, the vacuum layer along the normal direction is greater than 15 Å;

[0033] (2) Energy minimization was performed on the constructed Ga2O3 / WS2 ferroelectric heterojunction atomic structure model. DFT-D3 correction was used to study long-range van der Waals interactions. The cutoff energy was set to 600 eV and the energy convergence threshold was set to 10 eV. ⁻6 eV, the force convergence threshold is set to 0.01 eV / Å, and the reciprocal space k-point grid is set to 9×9×1;

[0034] (3) Obtain the band structure by inserting more than 20 data points between two high-symmetry points in the first Brillouin zone to accurately describe the band structure of the Ga2O3 / WS2 ferroelectric heterojunction. Since the PBE functional underestimates the band gap of semiconductor materials, the HSE06 hybrid functional is used to obtain the accurate band gap of the heterojunction.

[0035] (4) Obtain the differential charge density map of the Ga2O3 / WS2 ferroelectric heterojunction with a stable crystal structure. Calculate the charge density of the Ga2O3 / WS2, Ga2O3 monolayer, and WS2 monolayer respectively, and subtract the charge density of the Ga2O3 monolayer and WS2 monolayer from the charge density of Ga2O3 / WS2 to obtain the differential charge density;

[0036] (5) Obtain the electrostatic potential function and work function of the Ga2O3 / WS2 ferroelectric heterojunction after minimizing energy. Apply dipole correction to the Ga2O3 / WS2 ferroelectric heterojunction along the normal direction to prevent the two ends of the electrostatic potential function curve from drifting. The atomic structure model of the Ga2O3 / WS2 ferroelectric heterojunction includes two configurations: Ga2O3↓ / WS2 and Ga2O3↑ / WS2. According to the electrostatic potential function, the polarization direction of the Ga2O3↓ / WS2 configuration is determined to be from the WS2 layer to the Ga2O3 layer, and the polarization direction of the Ga2O3↑ / WS2 configuration is from the Ga2O3 layer to the WS2 layer.

[0037] (6) Based on the projected band structure of the Ga2O3 / WS2 ferroelectric heterojunction, calculate the band alignment, valence band offset (VBO), and conduction band offset (CBO) of the ferroelectric heterojunction.

[0038] (7) Based on the Bader charge of the Ga2O3 / WS2 ferroelectric heterojunction, calculate the Bader charge information of the Ga2O3 monolayer and WS2 monolayer that make up the ferroelectric heterojunction respectively, and determine the amount of Bader charge transferred between layers.

[0039] Non-adiabatic molecular dynamics simulations were performed using Hefei-NAMD software.

[0040] (1) Rotate the ferroelectric heterocrystalline structure after minimizing energy into an orthorhombic unit cell, and then expand the orthorhombic unit cell into a 3×3×1 orthorhombic supercell;

[0041] (2) Molecular dynamics simulation of a 3×3×1 orthogonal supercell was performed using the velocity adjustment method. The NVT ensemble was selected, and the cell was heated to 300K in 600fs with a time step of 1fs.

[0042] (3) Molecular dynamics simulation was performed using the NVE ensemble after thermal equilibrium at room temperature to generate 5ps dynamic trajectories with a time step of 1fs.

[0043] (4) Extract the last 2ps dynamic trajectory to obtain 2000 atomic structures and construct non-adiabatic molecular dynamics minimum surface jump samples;

[0044] (5) Obtain the projected energy level evolution diagram of the final 2ps dynamic trajectory;

[0045] (6) Obtain the wave function of the final 2ps dynamic trajectory sample for non-adiabatic molecular dynamics calculation;

[0046] (7) Randomly select 500 initial structures from the last 2ps dynamic trajectory samples to perform minimum surface jump calculation;

[0047] (8) Find the initial positions of electron and hole energy relaxation from the projected energy level evolution diagram, so that hot carriers condense to the band edge position;

[0048] (9) Since Ga2O3↓ / WS2 exhibits Type-II band alignment, the condensation time of hot carriers in the conduction band and valence band corresponds to the interlayer transfer time of electrons and holes, respectively.

[0049] (10) Since Ga2O3↑ / WS2 exhibits Type-III band alignment, only electron relaxation from the bottom of the conduction band to the valence band occurs;

[0050] (11) Obtain the interlayer transfer time of electrons and holes in the Ga2O3↓ / WS2 ferroelectric heterojunction and the electron transfer time in the Ga2O3↑ / WS2;

[0051] (12) Obtain different carrier recombination times in Ga2O3 / WS2 ferroelectric heterojunctions;

[0052] (13) Extract the 2ps dynamic trajectories of the valence band top and conduction band bottom of Ga2O3 / WS2 ferroelectric heterojunctions with different polarization directions, perform Fourier transform on these bands respectively, and obtain the Fourier transformation spectra of charge transfer and hole transfer, which are used to analyze the microscopic mechanism of carrier transfer.

[0053] Data statistical analysis:

[0054] (1) Polarization reversal significantly alters the electronic properties and band shift of the ferroelectric heterostructure, causing Ga2O3↓ / WS2 and Ga2O3↑ / WS2 to exhibit Type-II and Type-III band alignments, respectively, such as Figure 1 As shown, Figure 1 This is a projected band structure diagram of the Ga2O3↓ / WS2 and Ga2O3↑ / WS2 heterojunctions in embodiments of the present invention, wherein... Figure 1 (a) Figure 1 (d) in the figure represents the result of the HSE06 functional calculation; Figure 1 (b) Figure 1 (e) in the figure represents the result of the PBE functional calculation; Figure 1 (c) Figure 1 (f) corresponds to the band alignment method. HSE06 projection band structure calculations were performed on the stable crystal structure after energy minimization, yielding a band gap of 2.05 eV for Ga2O3↓ / WS2 and 0.12 eV for Ga2O3↑ / WS2. PBE projection band structure calculations were performed on the stable crystal structure after energy minimization, yielding a band gap of 1.67 eV for Ga2O3↓ / WS2 and 0.08 eV for Ga2O3↑ / WS2. The valence band top is mainly occupied by the WS2 layer, and the conduction band bottom is mainly occupied by the Ga2O3 layer. Based on the difference in occupied states between the valence band top and conduction band bottom, Ga2O3↓ / WS2 exhibits Type-II band alignment, and similarly, Ga2O3↑ / WS2 exhibits Type-III band alignment. The valence band offset ΔE of Ga2O3↓ / WS2 was determined. v =0.74eV and conduction band offset ΔE c =0.13eV; and Ga2O3↑ / WS2 valence band shift ΔE v =2.65eV and conduction band offset ΔE c =2.04eV;

[0055] (2) Figure 2 The figures show the electrostatic potential and differential charge density diagrams of Ga2O3↓ / WS2 and Ga2O3↑ / WS2 in embodiments of the present invention, wherein... Figure 2 (a) Figure 2 (b) Figure 2 (c) and Figure 2 In the figure, (d) represents the average electrostatic potential along the z-direction for WS2 monolayer, Ga2O3 monolayer, Ga2O3↓ / WS2, and Ga2O3↑ / WS2; the work function of the WS2 monolayer is Φ=5.60eV, and the work function of the Ga2O3 monolayer is Φ low =5.64eV and Φ high=8.22 eV; Electrons transfer from the low work function side to the high work function side of the heterojunction, eventually reaching electrostatic equilibrium; For the Ga2O3↓ / WS2 configuration, electrons transfer from the WS2 side (Φ=5.60 eV) to the Ga2O3 side (Φ=8.22 eV); low =5.64eV), according to Bader's charge, the charge transfer is 0.005e; for the Ga2O3↑ / WS2 configuration, electrons are transferred from the WS2 side (Φ=5.60eV) to the Ga2O3 side (Φ =5.64eV). high =8.22eV), and according to Bader's charge, the charge transfer amount is 0.02e. Figure 2 In the diagram, (e) represents the differential charge density of Ga2O3↓ / WS2, with the yellow area indicating charge accumulation and the cyan area indicating charge consumption. Figure 2 In the diagram, (f) represents the differential charge density of Ga2O3↑ / WS2, with the yellow area indicating charge accumulation and the cyan area indicating charge consumption.

[0056] (3) According to Figure 2 As can be seen from (e) in the figure, Ga2O3↓ / WS2 accumulates a large number of electrons, which repel the charge carriers and hinder the transport of charge carriers;

[0057] (4) Figure 3 As shown, Figure 3 The above are carrier relaxation dynamics diagrams of Ga2O3↓ / WS2 and Ga2O3↑ / WS2 at 300K in embodiments of the present invention. Figure 3 (a) Figure 3 In this context, (d) represents the change of electron energy over time. Figure 3 (b) and (c) in the figure represent the electron and hole transfer processes of different Ga2O3↓ / WS2 configurations; Figure 3 (e) in the diagram represents the hole transfer process in the Ga2O3↑ / WS2 configuration; Figure 3 In the diagram (f), the carrier recombination process occurs in two configurations. In the Ga2O3↓ / WS2 configuration, ultrafast hole transfer from the WS2 layer to the Ga2O3 layer takes 50 fs, while electron transfer from the Ga2O3 layer to the WS2 layer takes 321 fs. Furthermore, 15% of the hole transfer and 46% of the electron transfer occur between different layers. Therefore, this heterojunction exhibits high carrier separation efficiency, such as... Figure 3 (b) and Figure 3 As shown in (c); the charge transfer timescale of Ga2O3↑ / WS2 occurs at 82 fs, as... Figure 3 As shown in (e), the carrier recombination lifetime of Ga2O3↓ / WS2 (27 ps) is significantly greater than that of Ga2O3↑ / WS2 (2.46 ps), which is caused by the difference in their band gaps. The carrier recombination lifetime is significantly slower than the electron and hole transfer time, which means that electrons and holes have already transferred before carrier recombination, indicating that carriers are effectively separated.

[0058] (5) The hole-transfer phonon frequency of the Ga2O3↓ / WS2 ferroelectric heterojunction is approximately 740 cm⁻¹. -1 The charge-transfer phonon frequency is approximately 300 cm⁻¹. -1 Therefore, the slow charge transfer time is due to the phonon frequency lowering the nuclear velocity, weakening the non-adiabatic coupling, and hindering charge transfer, such as... Figure 4 As shown. The carrier transfer probability is related to the average nonadiabatic coupling (NAC), and can be expressed as:

[0059] ;

[0060] in, , Let ε represent the wavefunctions of the j-th and k-th electronic states, respectively; j and ε k Let represent the eigenvalues ​​of the j-th and k-th electronic states, respectively. H is the partial derivative of the Hamiltonian; H is the Hamiltonian. This refers to the velocity of the atomic nucleus. NAC reflects the wavefunction overlap between adjacent ion orbitals; the larger the NAC matrix element, the higher the transition probability of photogenerated carriers. The results show that the NAC value in the recombination region is significantly weaker than that in the carrier transfer region, indicating that the recombination timescale is much longer than the carrier transfer time. Figure 4 (a) and Figure 4 As shown in (b) above, carrier transfer in both ferroelectric heterojunctions mainly originates from the 440–460 cm⁻¹ region. −1 Nearby high-frequency phonons, which are related to the out-of-plane mode A of WS2. 1g For the Ga2O3↓ / WS2 configuration, high-frequency phonons (approximately 740 cm⁻¹) are associated with hole transfer. -1 The electrons are transferred to low-frequency phonons at a distance of approximately 300 cm⁻¹. -1 This results in faster nuclear motion speed and a larger NAC value, such as Figure 4 As shown in (c) in the figure. Therefore, the interlayer hole transfer time is significantly faster than the charge transfer time. The phonon frequencies of electron and hole transfer in the Ga2O3↑ / WS2 ferroelectric heterojunction are almost the same, such as Figure 4 As shown in (d) in the figure. Therefore, the timescale of carrier transfer in ferroelectric heterojunctions is jointly dominated by phonon frequency, interface charge accumulation, and bandgap width.

[0061] The above description is only a preferred embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any equivalent substitutions or modifications made by those skilled in the art within the scope of the technology disclosed in the present invention, based on the technical solution and inventive concept of the present invention, should be covered within the scope of protection of the present invention.

Claims

1. A method for enhancing carrier separation efficiency in Ga2O3 / WS2 based on polarization, characterized in that, Includes the following steps: S1. Construct atomic structure models of Ga2O3 / WS2 ferroelectric heterojunctions with different polarization directions, set a vacuum layer greater than 15 Å along the normal direction, and minimize the energy of the atomic structure models to obtain a stable crystal structure. S2. Based on the stable crystal structure obtained in S1, calculate the projected band structure, band alignment, electrostatic potential function, work function, differential charge density, and Bader charge respectively. S3. The atomic structure model of the Ga2O3 / WS2 ferroelectric heterojunction includes two configurations: Ga2O3↓ / WS2 and Ga2O3↑ / WS2. Based on the electrostatic potential function in S2, the polarization direction of the Ga2O3↓ / WS2 configuration is determined to be from the WS2 layer to the Ga2O3 layer, while the polarization direction of the Ga2O3↑ / WS2 configuration is from the Ga2O3 layer to the WS2 layer. The electron transfer direction is determined based on the work function and differential charge density, with electrons transferring from the WS2 layer (lower work function) to the Ga2O3 layer (higher work function). The charge transfer amount is determined based on the Bader charge. S4. The relaxation dynamics of carriers in Ga2O3 / WS2 ferroelectric heterojunctions with different polarization directions were simulated using non-adiabatic molecular dynamics methods. The ultrafast electron-hole interlayer transfer time and carrier recombination lifetime were obtained to determine that polarization causes photogenerated carriers to migrate in the opposite polarization direction.

2. The method for improving carrier separation efficiency based on polarization enhancement of Ga2O3 / WS2 according to claim 1, characterized in that, In S1, the energy minimization settings specifically include: introducing DFT-D3 van der Waals correction, setting the cutoff energy of the plane wave basis set to 600 eV, and setting the energy convergence threshold to 10 eV. -6 eV, the interatomic force convergence threshold is 0.01eV / Å, and the reciprocal space K-point grid is set to 9×9×1.

3. The method for improving carrier separation efficiency based on polarization enhancement of Ga2O3 / WS2 according to claim 1, characterized in that, In S2, when calculating the projected band structure, the HSE06 hybrid functional and PBE functional are used to calculate the projected band structure. The band alignment mode of the Ga2O3 / WS2 ferroelectric heterojunction is determined to be Type-II or Type-III through the projected band structure, and its valence band offset and conduction band offset are calculated. After applying dipole correction along the normal direction to the Ga2O3 / WS2 ferroelectric heterojunction, the electrostatic potential function and work function of the heterojunction, as well as the Ga2O3 monolayer and WS2 monolayer, are calculated. Calculate the charge density of the Ga2O3 / WS2, Ga2O3 monolayer and WS2 monolayer respectively, and subtract the charge density of the Ga2O3 monolayer and WS2 monolayer from the charge density of the Ga2O3 / WS2 monolayer to obtain the differential charge density; The Bader charge of the Ga2O3↓ / WS2 and Ga2O3↑ / WS2 ferroelectric heterojunctions is calculated separately, and the independent Bader charge information of the Ga2O3 monolayer and WS2 monolayer is extracted to determine the Bader charge amount of the Ga2O3 monolayer and WS2 monolayer that make up the heterojunction.

4. The method for improving carrier separation efficiency based on polarization enhancement of Ga2O3 / WS2 according to claim 1, characterized in that, S4 specifically includes: The crystal structure after minimizing the S1 energy is rotated into an orthorhombic unit cell, and the orthorhombic unit cell is expanded into a 3×3×1 orthorhombic supercell; A 3×3×1 orthogonal supercell was heated to 300K and reached thermodynamic equilibrium in an NVT ensemble over a time step of 1fs. Molecular dynamics simulations were performed on the orthogonal supercell after thermal equilibrium under the NVE ensemble, generating dynamic trajectories with a 5 ps time step and a 1 fs time step. Extract the final 2ps dynamic trajectory to obtain 2000 atomic structures, and construct non-adiabatic molecular dynamics minimum surface jump samples; The wave functions and projected energy levels of the 2000 dynamic trajectory samples were obtained for non-adiabatic molecular dynamics calculations, and 500 initial structures were randomly selected from them for minimum surface jump calculations. The initial positions of electron and hole energy relaxation are determined based on the time evolution of energy states, causing hot carriers to condense to the band edge positions, and the interlayer transfer time of electrons and holes is obtained; electrons relax from the top of the valence band to the bottom of the conduction band and recombine with holes, thus obtaining the recombination lifetime of the carriers.

5. The method for improving carrier separation efficiency based on polarization enhancement of Ga2O3 / WS2 according to claim 4, characterized in that, It also includes S5, which specifically involves: extracting the 2ps dynamic trajectories of the valence band top and conduction band bottom of the Ga2O3 / WS2 ferroelectric heterojunction with different polarization directions in S4, performing Fourier transforms on the 2ps dynamic trajectories respectively to obtain the characteristic phonon spectrum, determining the characteristic phonon frequency coupled with the electron-phonon in the carrier transfer process, and identifying the phonon mode that dominates the interlayer transfer of carriers.

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