A ferroelectric field regulated photoelectric detector based on a semi-metal MoTe2 / MoS2 heterojunction and a preparation method and application thereof

Abstract

The application relates to a ferroelectric field-regulated photoelectric detector based on a semi-metal MoTe2 / MoS2 heterojunction and a preparation method and application thereof. The structure of the photoelectric detector is sequentially arranged from bottom to top as an insulating substrate, a gate electrode, a ferroelectric functional layer, an oxide gate dielectric, a semiconductor MoS2 nanosheet, a semi-metal MoTe2 nanosheet and a metal source electrode and a metal drain electrode. The preparation steps are as follows: firstly, the gate electrode is prepared on the insulating substrate; then, the zirconium-doped hafnium oxide-based ferroelectric film is grown on the gate electrode by using an atomic layer deposition method; after high-temperature rapid annealing, the oxide gate dielectric is deposited; the semiconductor MoS2 nanosheet is transferred on the structure; the semi-metal MoTe2 nanosheet is obtained and transferred on the semiconductor MoS2 nanosheet; and finally, the metal source electrode and the metal drain electrode are prepared. Compared with the prior art, the application utilizes the strong local electric field generated by the residual polarization of the ferroelectric material to regulate the internal characteristics of the two-dimensional material, the two-dimensional semi-metal and the semiconductor are stacked to form a van der Waals Schottky junction, the dark current is inhibited, and the generation of the zero-bias photocurrent is promoted.

Description

Technical Field

[0001] This invention relates to the field of semiconductor device technology, and in particular to a ferroelectric field-controlled photodetector based on a half-metallic MoTe2 / MoS2 heterojunction, its fabrication method, and its application. Background Technology

[0002] Polarization detectors have a wide range of applications, including polarization sensors, biomedical imaging, and optoelectronic communications. With the rapid development of new information technologies such as artificial intelligence and autonomous driving, the large-scale integrated circuit industry faces demands for miniaturization, high-density integration, and low power consumption. However, common polarization detectors typically use optical media with specific structures such as plasmonic microcavities, quantum wells, and superlattices as polarization filters, which increases the size and complexity of the imaging system. In recent years, two-dimensional layered materials with anisotropic in-plane crystal structures, such as black phosphorus (BP), germanium arsenide (GeAs), and rhenium disulfide (ReS2), have been studied as photoactive thin films for polarization detection applications, circumventing the complex integration of optical filters. For example, a single-sided depletion-type BP infrared detector exhibits a polarization-sensitive light response at 830 nm with a polarization ratio of 2.66. Subsequently, various heterojunctions based on anisotropic two-dimensional semiconductor materials, such as GeSe / MoS2, MoS2 / GaAs, and WS2 / ReS2, have further improved polarization sensitivity by constructing type II band alignments and strong built-in electric fields. For example, the type II self-powered GeSe / MoTe2 pn heterojunction exhibits a broadband spectral coverage from the visible to near-infrared bands at 635 nm, with a polarization ratio of 5.4. Furthermore, two-dimensional semi-metallic materials such as 1T'-MoTe2, 1T'-WTe2, and TaIrTe4 are also candidates for polarization-sensitive photodetectors due to their low-symmetry structures. However, due to the properties of metals, the high dark current limits the sensitivity of photodetection, similar to that of conventional Schottky detectors based on metal-semiconductor contacts.

[0003] Therefore, there is an urgent need for a photodetector with excellent characteristics such as high-performance room-temperature photodetection, fast response, and excellent anisotropic photocurrent ratio in the visible light band. Summary of the Invention

[0004] The purpose of this invention is to overcome the shortcomings of the existing technology by providing a ferroelectric field-controlled photodetector based on a half-metal MoTe2 / MoS2 heterojunction, its fabrication method, and its applications. Ferroelectric materials are a class of dielectric materials with polarization characteristics. Applying an external voltage polarizes a ferroelectric material; after removing the voltage, its internal electric dipoles are neatly arranged, generating a large built-in electric field. Therefore, by combining ferroelectric materials with two-dimensional materials, the strong localized electric field generated by the residual polarization of the ferroelectric material can be used to control the internal properties of the two-dimensional material. Two-dimensional half-metals and semiconductors can be stacked to form a van der Waals-Schottky junction, which can suppress dark current and promote the generation of zero-bias photocurrent.

[0005] The objective of this invention can be achieved through the following technical solutions: The first objective of this invention is to provide a ferroelectric field-controlled photodetector based on a half-metallic MoTe2 / MoS2 heterojunction. The device structure of the photodetector, from bottom to top, is as follows: -Insulating substrate, -Gate electrode, -Ferroelectric functional layer -Oxide gate dielectric, - Semiconductor MoS2 nanosheets, - Semi-metallic MoTe2 nanosheets, -Metal source, metal drain The insulating substrate is a SiO2 / Si substrate, in which Si is heavily p-type doped and the thickness of the SiO2 layer is 300 nm. The gate electrode is made of titanium nitride with a thickness of 40±10 nm. The ferroelectric functional layer is a zirconium-doped hafnium oxide-based ferroelectric thin film with a thickness of 10±5 nm. The oxide gate dielectric is aluminum oxide with a thickness of 5±3 nm; The thickness of the semiconductor MoS2 nanosheets ranges from 5 to 50 nm; The thickness of the semi-metallic MoTe2 nanosheets ranges from 20 to 50 nm; Both the metal source and metal drain electrodes are pure gold electrodes with a gold thickness of 30-60 nm.

[0006] Furthermore, the photodetector utilizes the ferroelectric local electrostatic field of the ferroelectric functional layer (3) to modulate the half-metal MoTe2 / MoS2 heterojunction constructed from semiconductor MoS2 nanosheets (5) and half-metal MoTe2 nanosheets (6).

[0007] Furthermore, the photodetector modulates the ferroelectric local electrostatic field through a low gate voltage; the low gate voltage is 1.8V.

[0008] The second objective of this invention is to provide a method for fabricating a photodetector based on a ferroelectric field-controlled half-metal MoTe2 / MoS2 heterojunction, comprising the following steps: 1) SiO2 / Si substrate is selected as the insulating substrate, where Si is p-type heavily doped and the thickness of the SiO2 layer is 285±15nm.

[0009] 2) Fabrication of titanium nitride (TiN) gate electrode TiN was deposited as a gate electrode on a SiO2 / Si substrate by ion beam sputtering. The thickness was 40±10 nm. The deposition temperature was room temperature. The sputtering target was TiN. The sputtering beam current was 46 mA, the voltage was 800 V, and the accelerating voltage was 160 V.

[0010] 3) Fabrication of ferroelectric functional layers A zirconium (Zr)-doped hafnium oxide (HfO2) film with a thickness of 10 ± 5 nm was grown on a TiN bottom electrode using the ALD method. The precursors for Zr and Hf were tetrabis(ethylmethylamino)zirconium (Zr[N(C2H5)CH3]4) and tetrabis(ethylmethylamino)hafnium (Hf[N(C2H5)CH3]4), respectively. The growth temperature was 280 ℃, and the precursor for O was water (H2O). The chamber pressure was 2 mBar. By controlling the alternation cycle ratio of Hf and Zr to 1:1, the doping ratio of Zr was controlled to be 50%, i.e., the atomic ratio of Zr to Hf was 1:1.

[0011] Inert protective gas nitrogen (N2) is introduced into the annealing chamber for rapid annealing. The annealing temperature is 500 ℃ and the annealing time is 30 s. This allows the zirconium-doped hafnium oxide thin film to crystallize and form a ferroelectric phase as the ambient temperature rapidly decreases, thus obtaining a zirconium-doped hafnium oxide ferroelectric thin film, which is the ferroelectric functional layer.

[0012] A TiN top electrode with a thickness of 40 ± 10 nm was deposited on a zirconium-doped hafnium oxide ferroelectric thin film by ion beam sputtering. The zirconium-doped hafnium oxide ferroelectric thin film was then rapidly annealed for 30 seconds at 500 °C in a nitrogen atmosphere under the clamping action of the TiN top and bottom electrodes.

[0013] The electrode on TiN was removed by chemical etching with hydrogen peroxide aqueous solution.

[0014] 4) Fabrication of alumina gate dielectric Alumina gate dielectric was deposited on the ferroelectric functional layer using electron beam evaporation. The sample was placed in a vacuum chamber, and electron beam evaporation was performed on Hf... 0.5 Zr 0.5 Aluminum with a thickness of 3 nm was deposited on an O2 ferroelectric thin film. After deposition, the sample was removed and allowed to oxidize naturally in the air.

[0015] 5) Preparation of semiconductor MoS2 A mechanical exfoliation method was used to mechanically exfoliate semiconductor MoS2 nanosheets from an alumina gate dielectric.

[0016] Using a microscope, MoS2 nanosheets of appropriate thickness (green nanosheets) were selected as semiconductor MoS2 nanosheets.

[0017] 6) Preparation of half-metallic MoTe2 / MoS2 heterojunctions 1T'-MoTe2 nanosheets were mechanically exfoliated from a SiO2 / Si substrate using a mechanical exfoliation method. 1T'-MoTe2 nanosheets (yellow-green nanosheets) of suitable thickness were selected using a microscope as half-metallic MoTe2 nanosheets.

[0018] A PVA / PDMS film was adhered to the surface of the 1T'-MoTe2 nanosheets using a mechanical transfer method. The 1T'-MoTe2 nanosheets were then stacked onto semiconductor MoS2 nanosheets on an alumina gate dielectric to construct a half-metallic MoTe2 / MoS2 heterojunction.

[0019] The two sides of the semi-metallic MoTe2 nanosheet are in contact with an oxide gate dielectric and a semiconductor MoS2 nanosheet, respectively.

[0020] The PVA / PDMS film is obtained by uniformly applying a PVA solution onto a PDMS film and drying it at 50°C.

[0021] 7) Fabrication of source and drain electrodes Metal source and metal drain electrodes are prepared by using electron beam etching or ultraviolet lithography, combined with thermal evaporation and lift-off processes, forming semiconductor MoS2 nanosheets and half-metal MoTe2 nanosheets that correspond to the ohmic contacts of the metal source and metal drain electrodes, respectively.

[0022] 8) Apply a positive voltage pulse to the gate electrode to polarize the ferroelectric functional layer.

[0023] Furthermore, the concentration of the hydrogen peroxide aqueous solution is 30 wt%.

[0024] A third objective of this invention is to provide an application of a ferroelectric field-controlled photodetector based on a half-metallic MoTe2 / MoS2 heterojunction, which is used for visible light detection or polarized light detection.

[0025] The technical concept of this invention includes: This invention relates to a ferroelectric field-controlled photodetector based on a half-metal MoTe2 / MoS2 heterojunction, its fabrication method, and its applications. The photodetector structure, from bottom to top, comprises an insulating substrate, a gate electrode (TiN), a ferroelectric functional layer, an oxide gate dielectric, a semiconductor MoS2 nanosheet, a half-metal MoTe2 nanosheet, a metal source electrode, and a metal drain electrode. The fabrication steps of the photodetector are as follows: First, a gate electrode is fabricated on the insulating substrate using ion beam sputtering. A zirconium-doped hafnium oxide-based ferroelectric thin film is grown on the gate electrode using atomic layer deposition. After high-temperature rapid annealing, an oxide gate dielectric is deposited. Subsequently, semiconductor MoS2 nanosheets are transferred onto this structure using mechanical lift-off. Then, half-metal MoTe2 nanosheets are obtained through mechanical lift-off and transferred onto the semiconductor MoS2 nanosheets. Finally, the metal source electrode and metal drain electrode are fabricated using ultraviolet lithography or electron beam lithography combined with thermal evaporation and lift-off processes.

[0026] This invention replaces the traditional gate dielectric material in low-dimensional phototransistor devices with zirconium-doped hafnium oxide-based ferroelectric thin film material. It utilizes the ferroelectric local electrostatic field effect of the ferroelectric material to regulate the photoelectric response characteristics of the low-dimensional phototransistor, effectively suppressing dark current and improving photodetection efficiency. It can be applied to future fields such as low-photon and high-sensitivity photodetection.

[0027] Zirconium-doped hafnium oxide-based ferroelectric thin films offer advantages such as ultrathin thickness, semiconductor process compatibility, and environmental friendliness. Furthermore, the voltage amplification effect of ferroelectric field-effect transistors, utilizing the localized electric field formed by ferroelectric polarization, has been experimentally verified. In the dark state, electrons in the half-metal MoTe2 / MoS2 heterojunction are depleted by the ferroelectric localized field, suppressing dark current and reducing photodetector noise. Under illumination, photo-excited electrons are "pulled" towards the external circuit by the external electric field, while photo-excited holes are captured by the ferroelectric localized field, causing a decrease in the channel barrier. The residual polarization energy of the ferroelectric material remains stable, meaning that the detector does not require an external gate voltage during operation, reducing energy consumption. Two-dimensional half-metals and semiconductors can be stacked to form van der Waals-Schottky junctions, which can suppress dark current and promote the generation of zero-bias photocurrent.

[0028] Compared with the prior art, the beneficial effects of the present invention are as follows: The ferroelectric field-controlled photodetector based on a half-metallic MoTe2 / MoS2 heterojunction provided by this invention is a low-dimensional material photodetector structure. It utilizes a hafnium oxide-based ferroelectric thin film to replace the gate dielectric layer of a traditional phototransistor, maintaining the residual polarization energy of the ferroelectric material stably. This means the detector does not require an external gate voltage during operation, reducing energy consumption. Furthermore, the local electric field formed by ferroelectric polarization effectively modulates the channel barrier, significantly suppresses dark current, and substantially improves photodetection efficiency. In addition, the device also features good stability, simple structure, and ease of fabrication. Attached Figure Description

[0029] Figure 1 This is a schematic cross-sectional view of a photodetector based on a half-metallic MoTe2 / MoS2 heterojunction, designed for ferroelectric field modulation. In the figure: 1. Insulating substrate; 2. Gate electrode; 3. Ferroelectric functional layer; 4. Oxide gate dielectric; 5. Semiconductor MoS2 nanosheet; 6. Half-metallic MoTe2 nanosheet; 7. Metal source; 8. Metal drain.

[0030] Figure 2 A schematic diagram of the band structure of a photodetector based on a half-metallic MoTe2 / MoS2 heterojunction for ferroelectric field modulation. Figure 3 The current-voltage curve of the photodetector based on the half-metallic MoTe2 / MoS2 heterojunction, which is ferroelectric field regulated in Example 1, is shown.

[0031] Figure 4 The image shows the current-voltage curves of the photodetector based on the half-metallic MoTe2 / MoS2 heterojunction, which is ferroelectrically modulated according to Example 1, under different power of incident light at 635nm.

[0032] Figure 5 The graph shows the photoresponse versus time curves of the ferroelectric field-controlled photodetector based on the half-metallic MoTe2 / MoS2 heterojunction in Example 1 under zero bias at different incident light powers at 635nm.

[0033] Figure 6 The graph shows the photocurrent of the photodetector based on the half-metallic MoTe2 / MoS2 heterojunction, which is ferroelectrically modulated in Example 1, as a function of polarization angle under incident light at 635 nm.

[0034] Figure 7 This is a normalized photocurrent-angle polar plot of the photodetector based on a half-metallic MoTe2 / MoS2 heterojunction controlled by the ferroelectric field in Example 1, with incident light at 635 nm.

[0035] Figure 8 The current-voltage curve of the photodetector based on the half-metallic MoTe2 / MoS2 heterojunction, which is ferroelectric field regulated in Example 2, is shown.

[0036] Figure 9 The current-voltage curve is shown for the photodetector based on the ferroelectric field-controlled half-metal MoTe2 / MoS2 heterojunction in Example 3. Detailed Implementation

[0037] The present invention will now be described in detail with reference to the accompanying drawings and specific embodiments. The following embodiments will help those skilled in the art to further understand the present invention, but do not limit the invention in any way. It should be noted that those skilled in the art can make several modifications and improvements without departing from the concept of the present invention. These all fall within the protection scope of the present invention.

[0038] Any preparation methods, materials, structures, or composition ratios not explicitly described in this technical solution are considered common technical features disclosed in the prior art.

[0039] All raw materials used in the following examples are commercially available.

[0040] The following embodiment provides a ferroelectric field-controlled photodetector based on a half-metallic MoTe2 / MoS2 heterojunction. It utilizes the ferroelectric local electrostatic field effect of hafnium oxide-based ferroelectric thin film to control the photoelectric response characteristics of low-dimensional material phototransistors, effectively suppressing dark current and improving photodetection efficiency.

[0041] The following embodiments further provide a method for fabricating the above-mentioned ferroelectric field-controlled photodetector based on the half-metal MoTe2 / MoS2 heterojunction, with specific steps as follows: 1. Selection of insulating substrate 1 Insulating substrate 1 is a SiO2 / Si substrate.

[0042] 2. Preparation of titanium nitride gate electrode 2 Titanium nitride gate electrode 2 was deposited on silicon dioxide on a SiO2 / Si substrate by ion beam sputtering, which also serves as the TiN bottom electrode. The deposition temperature was room temperature, and the cavity pressure was 5 × 10⁻⁶. -2 Pa, sputtering target is TiN, sputtering beam current is 46 mA, voltage is 800 V, accelerating voltage is 160 V.

[0043] 3. Fabrication of Ferroelectric Functional Layer 3 A zirconium-doped hafnium oxide thin film was grown on a TiN bottom electrode using the ALD method. The precursors for Zr and Hf were tetrabis(ethylmethylamino)zirconium (Zr[N(C2H5)CH3]4) and tetrabis(ethylmethylamino)hafnium (Hf[N(C2H5)CH3]4), respectively. The growth temperature was 280 °C, and the precursor for O was water (H2O). The chamber pressure was 2 mBar. By controlling the alternation ratio of Hf and Zr at 1:1, the Zr doping ratio was controlled to be 50%. An inert protective gas, nitrogen (N2), was introduced into the annealing chamber. The annealing temperature was 500 °C, and the annealing time was 30 s. This allowed the zirconium-doped hafnium oxide thin film to crystallize and form a ferroelectric phase as the ambient temperature rapidly decreased, resulting in a zirconium-doped hafnium oxide ferroelectric thin film, i.e., ferroelectric functional layer 3. The zirconium-doped hafnium oxide ferroelectric thin film (Hf...)... 0.5 Zr 0.5 A TiN top electrode with a thickness of 40 nm was deposited on an O2 ferroelectric thin film using the ion beam sputtering method described above. The zirconium-doped hafnium oxide-based ferroelectric thin film was then rapidly annealed for 30 seconds at 500°C in a nitrogen atmosphere under the clamping effect of the TiN top and bottom electrodes. The TiN top electrode was removed using a chemical etching method with a 30 wt% aqueous hydrogen peroxide solution.

[0044] 4. Preparation of alumina gate dielectric 4 Using electron beam evaporation technology, in Hf 0.5 Zr 0.5 A 3 nm thick aluminum layer was deposited on the O2 ferroelectric thin film. After deposition, the sample was removed and allowed to oxidize naturally in the air to obtain an aluminum oxide insulating layer with a thickness of about 3 nm, which served as the aluminum oxide gate dielectric 4.

[0045] 5. Preparation of semiconductor MoS2 nanosheets Semiconductor MoS2 nanosheets were mechanically exfoliated from the alumina gate dielectric layer using a mechanical exfoliation method, and MoS2 nanosheets of appropriate thickness (green nanosheets) were selected as semiconductor MoS2 nanosheets 5 using a microscope.

[0046] 6. Preparation of half-metallic MoTe2 / MoS2 heterojunctions 1T'-MoTe2 nanosheets were mechanically exfoliated from a SiO2 / Si substrate. Using a microscope, 1T'-MoTe2 nanosheets of suitable thickness (yellow-green nanosheets) were selected as the semi-metallic MoTe2 nanosheets 6. Then, a PVA / PDMS film was mechanically transferred to the surface of the 1T'-MoTe2 nanosheets. The 1T'-MoTe2 nanosheets were stacked onto MoS2 nanosheets on an alumina gate dielectric layer to construct a semi-metallic MoTe2 / MoS2 heterojunction. The PVA / PDMS film was obtained by uniformly applying a PVA aqueous solution onto a PDMS film and drying it at 50°C. The two sides of the semi-metallic MoTe2 nanosheets 6 were in contact with the oxide gate dielectric 4 and the semiconductor MoS2 nanosheets 5, respectively.

[0047] 7. Fabrication of metal source electrode 7 and metal drain electrode 8 Metal source electrode patterns (7) and metal drain electrode patterns (8) were fabricated on half-metal MoTe2 nanosheets (6) and semiconductor MoS2 nanosheets (5) respectively using ultraviolet lithography. Thermal evaporation technology (vacuum thermal evaporation deposition rate of 0.1~0.3 nm / s, vacuum degree of 1×10⁻⁶) was then used. -4 (Pa) Prepare metal electrodes with pure gold 30-60nm; combine with a lift-off process to remove the metal film and obtain the metal source electrode 7 and metal drain electrode 8. The optional process of ultraviolet lithography includes: spin coating negative photoresist onto the sample, with a spin coating speed and time of 500 r / min for 30 s and 4000 r / min for 45 s, then heating the hot plate to 150 ℃ and placing the sample on the hot plate to bake for 2 min to remove the solvent in the photoresist; then, perform ultraviolet exposure for 10 s, development for 45 s, rinse the sample surface with deionized water to remove the residual developer, and blow the sample dry with nitrogen.

[0048] 8. Polarized ferroelectric functional layer Ferroelectric functional layer 3 was polarized by applying a positive pulse voltage (1.8V, 0.5ms) to gate electrode 2. A ferroelectric field-controlled photodetector based on a half-metallic MoTe2 / MoS2 heterojunction was fabricated, and its photoelectric response characteristics under 635nm wavelength illumination were measured, revealing excellent photoelectric detection performance.

[0049] Example 1 This embodiment provides a ferroelectric field-controlled photodetector based on a half-metallic MoTe2 / MoS2 heterojunction, and the cross-sectional view of the device is shown below. Figure 1 As shown.

[0050] The photodetector consists of the following components from bottom to top: 1. Insulating substrate; 2. Gate electrode; 3. Ferroelectric functional layer; 4. Oxide gate dielectric; 5. Semiconductor MoS2 nanosheet; 6. Semi-metallic MoTe2 nanosheet; 7. Metal source electrode; 8. Metal drain electrode.

[0051] The ferroelectric field-controlled photodetector based on the half-metallic MoTe2 / MoS2 heterojunction in this embodiment was prepared using the above-described method.

[0052] In this embodiment, the insulating substrate 1 is a SiO2 / Si substrate; Si is p-type heavily doped, and the SiO2 layer in the SiO2 / Si substrate has a thickness of 300 nm; the gate electrode 2 is titanium nitride with a thickness of 40 nm; the ferroelectric functional layer 3 is zirconium-doped hafnium oxide (a zirconium-doped hafnium oxide-based ferroelectric thin film) with the molecular formula Hf 0.5 Zr 0.5 O2, with a thickness of 10 nm; oxide gate dielectric 4 is aluminum oxide, prepared by electron beam evaporation, with a thickness of 3 nm; semiconductor MoS2 nanosheet 5 is multilayer molybdenum disulfide (MoS2), prepared by mechanical exfoliation, with a thickness of 30 nm; semi-metallic MoTe2 nanosheet is multilayer molybdenum ditelluride (MoTe2), prepared by mechanical exfoliation, with a thickness of 35 nm; metal source electrode 7 and metal drain electrode 8 are pure gold electrodes, prepared by ultraviolet lithography combined with thermal evaporation and exfoliation, with a gold thickness of 50 nm.

[0053] Figure 2 This is a schematic diagram of the band structure of a photodetector with a half-metal MoTe2 / MoS2 heterojunction. Two-dimensional half-metals and semiconductors can be stacked to form a van der Waals Schottky junction, which can suppress dark current and promote the generation of zero-bias photocurrent. Figure 3 The image shows the current-voltage curve of the ferroelectric field-controlled photodetector based on a half-metallic MoTe2 / MoS2 heterojunction in Example 1. The test results show that the ratio of the current at a bias voltage of 1 V to the current at a bias voltage of -1 V is approximately 60, indicating that the Schottky heterojunction photodetector has good rectification behavior. Figure 4 This is a current-voltage curve of the ferroelectric field-controlled photodetector based on a half-metallic MoTe2 / MoS2 heterojunction in Example 1, under different powers of incident light at 635 nm. From... Figure 4 As can be seen from this, the ferroelectric field-controlled photodetector based on the half-metallic MoTe2 / MoS2 heterojunction exhibits excellent photoelectric and photovoltaic effects under 635 nm incident light illumination, with an open-circuit voltage (V0). oc ) and short-circuit current (I sc The values ​​reached 0.36 V and 6.17 nA respectively, indicating that the photodetector has a large built-in electric field and good interface contact quality, exhibiting excellent photovoltaic characteristics. Figure 5 This is a graph showing the photoresponse versus time curves of the ferroelectric field-controlled photodetector based on a half-metallic MoTe2 / MoS2 heterojunction in Example 1 under zero bias with different incident light powers at 635 nm. Figure 5It can be seen that the on-state and off-state current changes of the photodetector based on the half-metallic MoTe2 / MoS2 heterojunction controlled by the ferroelectric field are stable and repeatable under different power incident light, and have excellent photoresponse switching characteristics. Figure 6 The graph shows the photocurrent of the photodetector based on the half-metallic MoTe2 / MoS2 heterojunction, which is ferroelectrically modulated in Example 1, as a function of polarization angle under incident light at 635 nm. Figure 7 This is a normalized photocurrent-angle polar plot of the ferroelectric field-controlled photodetector based on a half-metallic MoTe2 / MoS2 heterojunction in Example 1, with incident light at 635 nm. Figure 6 and 7 It can be seen that the photodetector based on the half-metallic MoTe2 / MoS2 heterojunction, which is ferroelectric field regulated, exhibits cloverleaf-shaped polarized photocurrent behavior under 635nm illumination, with a polarization ratio of 4.5.

[0054] Example 2 This embodiment provides a ferroelectric field-controlled photodetector based on a half-metallic MoTe2 / MoS2 heterojunction, and the cross-sectional view of the device is shown below. Figure 1 As shown.

[0055] The photodetector consists of the following components from bottom to top: 1. Insulating substrate; 2. Gate electrode; 3. Ferroelectric functional layer; 4. Oxide gate dielectric; 5. Semiconductor MoS2 nanosheet; 6. Semi-metallic MoTe2 nanosheet; 7. Metal source electrode; 8. Metal drain electrode.

[0056] The ferroelectric field-controlled photodetector based on the half-metallic MoTe2 / MoS2 heterojunction in this embodiment was prepared using the above-described method.

[0057] In this embodiment, the insulating substrate 1 is a SiO2 / Si substrate; Si is p-type heavily doped, and the SiO2 layer in the SiO2 / Si substrate has a thickness of 300 nm; the gate electrode 2 is titanium nitride with a thickness of 40 nm; the ferroelectric functional layer 3 is zirconium-doped hafnium oxide (a zirconium-doped hafnium oxide-based ferroelectric thin film) with the molecular formula Hf 0.5 Zr 0.5 O2, with a thickness of 10 nm; oxide gate dielectric 4 is aluminum oxide, prepared by electron beam evaporation, with a thickness of 3 nm; semiconductor MoS2 nanosheet 5 is multilayer molybdenum disulfide, prepared by mechanical exfoliation, with a thickness of 10 nm; half-metal MoTe2 nanosheet is multilayer molybdenum ditelluride, prepared by mechanical exfoliation, with a thickness of 20 nm; metal source electrode 7 and metal drain electrode 8 are pure gold electrodes, prepared by ultraviolet lithography combined with thermal evaporation and exfoliation, with a gold thickness of 50 nm.

[0058] Figure 8The image shows the current-voltage curve of the ferroelectric field-controlled photodetector based on a half-metallic MoTe2 / MoS2 heterojunction in Example 2. The test results show that the ratio of the current at a bias voltage of 1 V to the current at a bias voltage of -1 V is approximately 370, indicating that this Schottky heterojunction photodetector exhibits excellent rectification behavior.

[0059] Example 3 This embodiment provides a ferroelectric field-controlled photodetector based on a half-metallic MoTe2 / MoS2 heterojunction, and the cross-sectional view of the device is shown below. Figure 1 As shown.

[0060] The photodetector consists of the following components from bottom to top: 1. Insulating substrate; 2. Gate electrode; 3. Ferroelectric functional layer; 4. Oxide gate dielectric; 5. Semiconductor MoS2 nanosheet; 6. Semi-metallic MoTe2 nanosheet; 7. Metal source electrode; 8. Metal drain electrode.

[0061] The ferroelectric field-controlled photodetector based on a half-metallic MoTe2 / MoS2 heterojunction in this embodiment was prepared using the above-described method. In this embodiment, the insulating substrate 1 is a SiO2 / Si substrate; Si is heavily p-type doped, and the SiO2 layer in the SiO2 / Si substrate has a thickness of 300 nm; the gate electrode 2 is titanium nitride with a thickness of 40 nm; the ferroelectric functional layer 3 is zirconium-doped hafnium oxide (a zirconium-doped hafnium oxide-based ferroelectric thin film) with the molecular formula Hf. 0.5 Zr 0.5 O2, with a thickness of 10 nm; oxide gate dielectric 4 is aluminum oxide, prepared by electron beam evaporation, with a thickness of 3 nm; semiconductor MoS2 nanosheet 5 is multilayer molybdenum disulfide, prepared by mechanical exfoliation, with a thickness of 15 nm; semi-metallic MoTe2 nanosheet is multilayer molybdenum ditelluride, prepared by mechanical exfoliation, with a thickness of 42 nm; metal source electrode 7 and metal drain electrode 8 are pure gold electrodes, prepared by ultraviolet lithography combined with thermal evaporation and exfoliation, with a gold thickness of 50 nm.

[0062] Figure 9 The image shows the current-voltage curves of the ferroelectric field-controlled photodetector based on a half-metallic MoTe2 / MoS2 heterojunction in Example 3. The test results show that the ratio of the current at a bias voltage of 1 V to the current at a bias voltage of -1 V is approximately 10, indicating that the Schottky heterojunction photodetector exhibits good rectification behavior.

[0063] Comparative Example 1 This comparative example provides a ferroelectric field-controlled photodetector based on MoS2 transistors. The difference from Example 1 is that in this comparative example, semiconductor MoS2 nanosheets are used instead of the heterojunction of semiconductor MoS2 nanosheets and half-metal MoTe2 nanosheets.

[0064] The photodetector consists of the following components from bottom to top: 1. Insulating substrate; 2. Gate electrode; 3. Ferroelectric functional layer; 4. Oxide gate dielectric; 5. Semiconductor MoS2 nanosheet; 6. Metal source electrode; 7. Metal drain electrode.

[0065] The ferroelectric field-controlled photodetector based on MoS2 transistors in this comparative example was fabricated using the above-described method. In this embodiment, the insulating substrate 1 is a SiO2 / Si substrate; Si is heavily p-type doped, and the SiO2 layer in the SiO2 / Si substrate has a thickness of 300 nm; the gate electrode 2 is titanium nitride with a thickness of 40 nm; the ferroelectric functional layer 3 is zirconium-doped hafnium oxide (a zirconium-doped hafnium oxide-based ferroelectric thin film) with the molecular formula Hf. 0.5 Zr 0.5 The photodetector has an O2 content of 10 nm; an oxide gate dielectric 4 is aluminum oxide, prepared by electron beam evaporation, with a thickness of 3 nm; a semiconductor MoS2 nanosheet 5 is multilayer molybdenum disulfide, prepared by mechanical exfoliation, with a thickness of 30 nm; and metal source 6 and metal drain 7 are pure gold electrodes, prepared by ultraviolet lithography combined with thermal evaporation and exfoliation, with a gold thickness of 50 nm. This photodetector cannot perform polarization photodetection, nor can it perform photodetection at a 0V bias voltage.

[0066] The above description of the embodiments is provided to enable those skilled in the art to understand and use the invention. It will be apparent to those skilled in the art that various modifications can be made to these embodiments, and the general principles described herein can be applied to other embodiments without inventive effort. Therefore, the present invention is not limited to the above embodiments, and any improvements and modifications made by those skilled in the art based on the disclosure of the present invention without departing from the scope of the invention should be within the protection scope of the present invention.

Claims

1. A ferroelectric field-controlled photodetector based on a half-metallic MoTe2 / MoS2 heterojunction, characterized in that, The photodetector includes, from bottom to top, an insulating substrate (1), a gate electrode (2), a ferroelectric functional layer (3), an oxide gate dielectric (4), a semiconductor MoS2 nanosheet (5), and a half-metal MoTe2 nanosheet (6), and also includes a metal source electrode (7) disposed on the semiconductor MoS2 nanosheet (5) and a metal drain electrode (8) disposed on the half-metal MoTe2 nanosheet (6); The insulating substrate (1) is a SiO2 / Si substrate; The gate electrode (2) is titanium nitride with a thickness of 30-50 nm; The ferroelectric functional layer (3) is a zirconium-doped hafnium oxide-based ferroelectric thin film with a thickness of 5-15 nm; The oxide gate dielectric (4) is aluminum oxide with a thickness of 2-8 nm; The thickness of the semiconductor MoS2 nanosheets (5) ranges from 5 to 50 nm; The thickness of the semi-metallic MoTe2 nanosheets (5) ranges from 20 to 50 nm; The metal source electrode (7) and metal drain electrode (8) are both pure gold electrodes with a gold thickness of 30-60 nm.

2. The photodetector based on a ferroelectric field-controlled half-metal MoTe2 / MoS2 heterojunction according to claim 1, characterized in that, The photodetector utilizes the ferroelectric local electrostatic field of the ferroelectric functional layer (3) to modulate the half-metal MoTe2 / MoS2 heterojunction constructed from semiconductor MoS2 nanosheets (5) and half-metal MoTe2 nanosheets (6).

3. The application of a ferroelectric field-controlled photodetector based on a half-metallic MoTe2 / MoS2 heterojunction according to claim 2, characterized in that, The photodetector modulates the ferroelectric local electrostatic field through a low gate voltage. The low gate voltage is 1.8V.

4. A method for fabricating a photodetector based on a half-metallic MoTe2 / MoS2 heterojunction with ferroelectric field modulation as described in any one of claims 1-3, characterized in that, The preparation method includes the following steps: 1) SiO2 / Si substrate was selected as the insulating substrate (1); 2) A gate electrode is deposited on a SiO2 / Si substrate by ion beam sputtering (2); 3) A zirconium-doped hafnium oxide thin film is grown on the gate electrode (2) by the ALD method; 4) Perform rapid annealing so that the zirconium-doped hafnium oxide thin film crystallizes to form a ferroelectric phase as the ambient temperature decreases, and obtain the zirconium-doped hafnium oxide ferroelectric thin film, which is the ferroelectric functional layer (3). 5) A TiN top electrode was deposited on the ferroelectric functional layer (3) by ion beam sputtering with a thickness of 40 nm. The ferroelectric functional layer (3) was then rapidly annealed under the clamping action of the TiN top electrode and the gate electrode (2). 6) Remove the electrodes on TiN using a chemical etching method with hydrogen peroxide aqueous solution; 7) An oxide gate dielectric (4) is deposited on the ferroelectric functional layer (3) by electron beam evaporation; 8) Semiconductor MoS2 nanosheets (5) were prepared on the surface of oxide gate dielectric (4) by mechanical exfoliation; 9) The semi-metallic MoTe2 nanosheets (6) are transferred and stacked onto the semiconductor MoS2 nanosheets (5) on the surface of the oxide gate dielectric (4) using mechanical peeling and mechanical transfer methods. The two sides of the semi-metallic MoTe2 nanosheets (6) are in contact with the oxide gate dielectric (4) and the semiconductor MoS2 nanosheets (5), respectively. 10) Using ultraviolet lithography or electron beam etching, metal source electrode (7) and metal drain electrode (8) are prepared by combining photolithography electrode patterns on semiconductor MoS2 nanosheet (5) with thermal evaporation and lift-off process; 11) Apply a positive voltage pulse to the gate electrode to polarize the ferroelectric functional layer (3).

5. The method for fabricating a ferroelectric field-controlled photodetector based on a half-metallic MoTe2 / MoS2 heterojunction according to claim 4, characterized in that, In step (1), the Si in the SiO2 / Si substrate is p-type heavily doped, and the thickness of the SiO2 layer is 270~300 nm; In step (3), the growth temperature is 280 °C, and the doping ratio of zirconium is controlled to be 50% by controlling the alternation cycle ratio of hafnium and zirconium elements to be 1:

1.

6. The method for fabricating a ferroelectric field-controlled photodetector based on a half-metallic MoTe2 / MoS2 heterojunction according to claim 4, characterized in that, In step (4), the rapid annealing conditions are: rapid annealing for 30 seconds in a nitrogen atmosphere at 500°C.

7. The method for fabricating a ferroelectric field-controlled photodetector based on a half-metallic MoTe2 / MoS2 heterojunction according to claim 4, characterized in that, In step (5), the deposition thickness of the TiN top electrode is 30~50nm.

8. The method for fabricating a ferroelectric field-controlled photodetector based on a half-metallic MoTe2 / MoS2 heterojunction according to claim 4, characterized in that, In step (6), the rapid annealing conditions are: rapid annealing for 30 seconds in a nitrogen environment at 500°C.

9. The method for fabricating a ferroelectric field-controlled photodetector based on a half-metallic MoTe2 / MoS2 heterojunction according to claim 4, characterized in that, In step (7), the concentration of the hydrogen peroxide aqueous solution is 30 wt%.

10. An application of a photodetector based on a half-metallic MoTe2 / MoS2 heterojunction with ferroelectric field modulation as described in any one of claims 1-3, characterized in that, The photodetector is used for visible light detection or polarized light detection.

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