Ga-gaas nanomaterial, preparation method thereof and photoelectric detector

Abstract

The application provides a Ga-GaAs nanomaterial, a preparation method thereof and a photoelectric detector, and comprises the following steps: reacting tris(dimethylamino) gallium dimer C 12 H 36 Ga2N6 and triphenylarsine in octadecene to obtain the Ga-GaAs nanomaterial. The preparation method is a one-step method, specific organic gallium source-tris(dimethylamino) gallium dimer and triphenylarsine are used as precursors, the reaction source is directly injected into a low-temperature liquid-phase system, and the Ga-GaAs nanomaterial with a high dispersion and excellent photoelectric performance and a structure similar to a wash ear is synthesized in the octadecene system. In the above reaction, all the reaction sources are directly injected into the reaction system in one step, the operation is simple, and high-quality products are easy to synthesize. The application also successfully constructs a visible and near-infrared photoelectric detector of the Ga-GaAs nanomaterial with high response, the device structure is simple, the performance is excellent, the stability and repeatability are good, and the device has great application prospects in the visible and near-infrared wave bands.

Description

Technical Field

[0001] This invention belongs to the field of nanomaterials technology, and particularly relates to a Ga-GaAs nanomaterial, its preparation method, and a photodetector. Background Technology

[0002] GaAs is a group III-V semiconductor material with high carrier mobility and a narrow bandgap. Based on its specific electronic structure and optical properties, GaAs has great potential for fabricating electronic and optoelectronic devices, and is particularly suitable for applications in various near-infrared regions. Therefore, the synthesis and preparation of GaAs is of great research significance.

[0003] A photodetector is a device that converts optical signals into electrical signals, and it plays an important role in many fields. Photodetectors can be used in optical communication, lidar, medical diagnostics, security monitoring, and other areas, improving the efficiency and accuracy of information transmission, scene perception, physiological monitoring, and security assurance. Summary of the Invention

[0004] In view of this, the purpose of this invention is to provide a Ga-GaAs nanomaterial, a method for preparing the same, and a photodetector. This method is a one-step process that can obtain Ga-GaAs nanomaterials with high dispersibility and excellent photoelectric properties.

[0005] This invention provides a method for preparing Ga-GaAs nanomaterials, comprising the following steps:

[0006] tris(dimethylamino)gallium dimer C 12 H 36 Ga2N6 and triphenylarsine react in octadecene to obtain Ga-GaAs nanomaterials.

[0007] Preferably, the molar ratio of the tris(dimethylamino)gallium dimer to triphenylarsine is 0.15:(0.1-0.3);

[0008] The volume ratio of octadecene to triphenylarsine was (10–15) mL: (0.1–0.3) mmol.

[0009] Preferably, the reaction temperature is 300–330°C and the reaction time is 10–30 min.

[0010] Preferably, the reaction is carried out under protective gas conditions.

[0011] Preferably, the preparation method specifically includes:

[0012] tris(dimethylamino)gallium dimer C 12 H 36Ga2N6 and triphenylarsine form a mixture in octadecene;

[0013] The mixture was injected into octadecene at a rate of 0.4–0.5 mL / min to react and obtain Ga-GaAs nanomaterials.

[0014] Preferably, the ratio of triphenylarsine to octadecene in the mixture is 0.30 mmol:(1-3) mL;

[0015] The ratio of tri(dimethylamino)gallium dimer to octadecene is 0.15 mmol:(1-3) mL.

[0016] Preferably, the volume ratio of octadecene to octadecene at 280–320°C used to prepare the mixture is (1–3):(7–14).

[0017] This invention provides a Ga-GaAs nanomaterial prepared by the preparation method described in the above technical solution.

[0018] This invention provides a photodetector, which is prepared by the following method:

[0019] Choose a suitable substrate as the base material;

[0020] Choose a suitable conductive layer as the top layer material;

[0021] The Ga-GaAs nanomaterial described in the above technical solution is used as an intermediate layer and coated on the substrate surface to obtain a Ga-GaAs nanomaterial layer; a conductive layer is then deposited on the surface of the Ga-GaAs nanomaterial layer.

[0022] A photodetector was obtained by using the bottom material and the top material as electrodes, respectively.

[0023] Preferably, the substrate is selected from p-type silicon wafers, n-type silicon wafers, or FTO;

[0024] The conductive layer is a single-layer graphene layer.

[0025] This invention provides a method for preparing Ga-GaAs nanomaterials, comprising the following steps: preparing tris(dimethylamino)gallium dimer C 12 H 36Ga₂N₆ and triphenylarsine react in octadecene to obtain Ga-GaAs nanomaterials. The preparation method provided by this invention is a one-step process. Using a specific organic gallium source—tris(dimethylamino)gallium dimer and triphenylarsine—as precursors, the reaction sources are directly injected into a low-temperature liquid-phase system to synthesize highly dispersed Ga-GaAs nanomaterials with excellent photoelectric properties in an octadecene system. In the above reaction, all reaction sources are directly injected into the reaction system in one step, simplifying the operation and facilitating the synthesis of high-quality products. This invention also successfully constructed visible and near-infrared photodetectors with high response Ga-GaAs nanomaterials. The devices have simple structures, excellent performance, good stability and repeatability, and show great application potential in the visible and near-infrared bands. Attached Figure Description

[0026] Figure 1 This is a SEM image of the Ga-GaAs nanomaterial obtained in Example 1 of the present invention;

[0027] Figure 2 The image shows a TEM image of the Ga-GaAs nanomaterial obtained in Example 1 of this invention.

[0028] Figure 3 The image shows the XRD pattern of the Ga-GaAs nanomaterial obtained in Example 1 of this invention.

[0029] Figure 4 The image shows the XPS pattern of the Ga-GaAs nanomaterial obtained in Example 1 of this invention; wherein, Figure 4 a is the total XPS spectrum of Ga-GaAs nanomaterials. Figure 4 b is the fine spectrum of Ga 3d. Figure 4 c is the fine spectrum of As 3d;

[0030] Figure 5 The image shown is an HRTEM image of the Ga-GaAs nanomaterial obtained in Example 1 of this invention; wherein... Figure 5 a is an HRTEM image of Ga-GaAs nanomaterials. Figure 5 b is a selected area calibration diagram of Ga-GaAs nanomaterials;

[0031] Figure 6 This image shows a high-angle annular dark-field image (HAADF-STEM) of the Ga-GaAs nanomaterials obtained in Example 1 of this invention, as well as mapping images of the two basic elements, Ga and As; wherein, Figure 6 Image a is a high-angle annular dark field image. Figure 6 In the diagram, b represents the mapping graph of the As element. Figure 6 In the diagram, c represents the mapping graph of Ga elements. Figure 6 In the image, d represents the distribution of Ga and As elements in the high-angle annular dark field image.

[0032] Figure 7 The characteristic absorption spectrum of the Ga-GaAs nanomaterial obtained in Example 1 of this invention is shown below.

[0033] Figure 8 This is a schematic diagram of the structure of the photodetector fabricated in Embodiment 1 of the present invention;

[0034] Figure 9 The photodetector obtained in Embodiment 1 of the present invention operates at a light intensity of 3 mW / cm². 2 Current-voltage (IV) curves at different wavelengths;

[0035] Figure 10 The photodetector obtained in Embodiment 1 of the present invention operates at a light intensity of 3 mW / cm². 2 Below, the transient current response (It) curves at different wavelengths are obtained by controlling the illumination.

[0036] Figure 11 The image shows the current-voltage (IV) curves of the photodetector obtained in Embodiment 1 of the present invention at different light intensities at a wavelength of 808 nm.

[0037] Figure 12 The image shows the transient current response It curves of the photodetector obtained in Embodiment 1 of the present invention at a wavelength of 808nm, obtained by controlling the illumination to obtain different light intensities.

[0038] Figure 13 The image shows the characterization of the Ga-GaAs nanomaterials obtained by Comparative Example 1 of this invention at an injection rate of 4 mL / min; where a is the TEM image of the obtained Ga-GaAs nanomaterials and b is the XRD image of the obtained Ga-GaAs nanomaterials.

[0039] Figure 14 The image shows the characterization of the Ga-GaAs nanomaterials obtained by Comparative Example 2 of this invention at an injection rate of 1 mL / min; where a is the TEM image of the obtained Ga-GaAs nanomaterials and b is the XRD image of the obtained Ga-GaAs nanomaterials.

[0040] Figure 15 The image shows the characterization of the Ga-GaAs nanomaterials obtained by Comparative Example 3 of this invention at an injection rate of 0.7 mL / min; where a is the TEM image of the obtained Ga-GaAs nanomaterials, b is the XRD pattern of the obtained Ga-GaAs nanomaterials, and c is the transient current response It curve of the photodetector prepared from the obtained Ga-GaAs nanomaterials at a light wavelength of 808 nm, obtained by controlling the illumination at different light intensities. Detailed Implementation

[0041] This invention provides a method for preparing Ga-GaAs nanomaterials, comprising the following steps:

[0042] tris(dimethylamino)gallium dimer (C 12 H 36 Ga2N6 and triphenylarsine (As(Ph)3) react in octadecene to obtain Ga-GaAs nanomaterials.

[0043] In this invention, the molar ratio of the tris(dimethylamino)gallium dimer to triphenylarsine is 0.15:(0.1-0.3). In a specific embodiment, the molar ratio of the tris(dimethylamino)gallium dimer to triphenylarsine is 0.15:0.3.

[0044] In this invention, the volume ratio of octadecene to triphenylarsine is (10-15) mL:(0.1-0.3) mmol, preferably (10-12) mL:(0.1-0.3) mmol. In a specific embodiment, the volume ratio of octadecene to triphenylarsine is 10 mL:(0.1-0.3) mmol.

[0045] The above preparation method specifically includes:

[0046] tris(dimethylamino)gallium dimer C 12 H 36 Ga2N6 and triphenylarsine form a mixture in octadecene;

[0047] The mixture was injected into octadecene at a rate of 0.4–0.5 mL / min to react and obtain Ga-GaAs nanomaterials.

[0048] In the mixture described in this invention, the ratio of tris(dimethylamino)gallium dimer to octadecene is 0.15 mmol:(1-3) mL. In a specific embodiment of this invention, the ratio of tris(dimethylamino)gallium dimer to octadecene is 0.15 mmol:2 mL.

[0049] In this invention, the ratio of triphenylarsine to octadecene in the mixture is 0.30 mmol:(1-3) mL; in a specific embodiment, the ratio of triphenylarsine to octadecene is 0.30 mmol:2 mL.

[0050] In this invention, the reaction is carried out under a protective gas condition. There are no special limitations on the type of protective gas; any conventional protective gas well-known to those skilled in the art, such as nitrogen or argon, is acceptable. There are no special limitations on the gas pressure of the reaction; atmospheric pressure is sufficient.

[0051] In this invention, octadecene is preferably placed in a reaction vessel and heated to 110-130°C and held for 30-40 minutes to remove moisture and low-boiling-point impurities; in a specific embodiment, the temperature is raised to 110°C and held for 40 minutes.

[0052] In this invention, the low-cost, stable arsenic source has low reactivity, while the gallium source has extremely high reactivity and is easily oxidized. Therefore, they need to be mixed and injected together into the system. On one hand, considering only the solution-liquid-solid reaction mechanism, generally, rapid injection of the mixture is needed to supersaturate the reactant precursor sources, thereby generating activity and growing crystals. However, in practice, rapid injection of the mixture into the system can cause the highly active gallium source to react rapidly and form elemental gallium before the less active arsenic source becomes active, thus losing its activity and being unable to react with the arsenic source. On the other hand, to increase the activity of the less active arsenic source and enable it to react, the reaction temperature needs to be increased. However, at the same time, the highly active gallium source will also become more reactive and more likely to form elemental gallium. Therefore, it is necessary to consider an appropriate injection rate and temperature to balance the coexistence of the highly active gallium source and the less active arsenic source in the system, thereby generating the desired gallium arsenide nanomaterials.

[0053] In this invention, the mixture is injected into octadecene at a rate of 0.4–0.5 mL / min to react and obtain Ga-GaAs nanomaterials at 280–320 °C. When the injection rate is 4 mL / min, almost no GaAs tails are formed. As the injection rate decreases, the GaAs tails gradually become longer, the crystallinity and quality gradually improve, and the photoelectric properties are enhanced. When the injection rate is 0.4 mL / min, highly dispersed Ga-GaAs nanomaterials with excellent photoelectric properties and a bulb-like structure can be obtained. As the injection rate continues to decrease, the degree of complexation between the gallium source in the mixture and water in the external environment increases, which is detrimental to the reaction. Therefore, the injection rate of the present invention is 0.4 to 0.5 mL / min; specifically, it can be 0.4 mL / min, 0.41 mL / min, 0.42 mL / min, 0.43 mL / min, 0.44 mL / min, 0.45 mL / min, 0.46 mL / min, 0.47 mL / min, 0.48 mL / min, 0.49 mL / min or 0.5 mL / min.

[0054] In this invention, tris(dimethylamino)gallium dimer C 12 H 36 The reaction of Ga2N6 and triphenylarsine in octadecene is carried out at a temperature of 300–330°C for a time of 10–30 min. In a specific embodiment, the reaction temperature is 320°C and the reaction time is 30 min.

[0055] In this invention, the volume ratio of octadecene to octadecene at 280–320°C used to prepare the mixture is (1–3):(7–14). In a specific embodiment, the volume ratio of octadecene to octadecene at 320°C used in the mixture is 2:10.

[0056] The present invention preferably involves cooling and washing after the reaction is completed; the cooling method is natural cooling; the solvent used for washing is preferably a mixture of n-hexane and anhydrous ethanol; the product is washed repeatedly.

[0057] Compared with other gas-phase growth methods, the low-temperature one-step method of this invention significantly reduces the reaction temperature and time, is easy to operate, and produces high-quality products that are easy to synthesize, making it suitable for large-scale applications in actual production.

[0058] The present invention also provides a Ga-GaAs nanomaterial prepared by the preparation method described in the above technical solution.

[0059] To demonstrate that Ga-GaAs nanomaterials possess photoelectric response properties, this invention also provides a photodetector, prepared according to the following method:

[0060] Choose a suitable substrate as the base material;

[0061] Choose a suitable conductive layer as the top layer material;

[0062] The Ga-GaAs nanomaterial described in the above technical solution is used as an intermediate layer and coated on the substrate surface to obtain a Ga-GaAs nanomaterial layer; a conductive layer is then deposited on the surface of the Ga-GaAs nanomaterial layer.

[0063] A photodetector was obtained by using the bottom material and the top material as electrodes, respectively.

[0064] The substrate described in this invention is selected from p-type silicon wafers, n-type silicon wafers, or FTO; the conductive layer is a single-layer graphene layer.

[0065] In a specific embodiment, the substrate is an n-type silicon wafer, and the conductive layer is a single-layer graphene layer. The Ga-GaAs nanomaterials prepared by the above method are uniformly spin-coated onto the n-type silicon wafer using a spin coater. A small portion of insulating tape is attached to one side of the sample on the n-type silicon wafer. Graphene of the same size as the silicon wafer is then tightly adhered to the upper surface of the sample. The lower n-type silicon wafer and the upper graphene layer serve as two electrodes, forming a three-layer vertical structure to obtain a photodetector (specifically as shown in the image). Figure 8 (As shown).

[0066] The preparation method provided by this invention is a one-step process. Using a specific organic gallium source—tris(dimethylamino)gallium dimer and triphenylarsine—as precursors, highly dispersed Ga-GaAs nanomaterials with excellent photoelectric properties are synthesized in an octadecene system by directly injecting the reaction sources into a low-temperature liquid-phase system. In the above reaction, all reaction sources are directly injected into the reaction system in one step, simplifying the operation and facilitating the synthesis of high-quality products. This invention also successfully constructed visible and near-infrared photodetectors with high response Ga-GaAs nanomaterials. The devices have simple structures, excellent performance, good stability and repeatability, and show great application potential in the visible and near-infrared bands.

[0067] To further illustrate the present invention, the following detailed description, in conjunction with embodiments, provides a Ga-GaAs nanomaterial, its preparation method, and a photodetector provided by the present invention. However, these descriptions should not be construed as limiting the scope of protection of the present invention.

[0068] Example 1

[0069] 1. Sample preparation:

[0070] Add 10 mL of octadecene to a 100 mL three-necked flask. Under the stirring of a high-temperature magnetic stirrer and in a reaction atmosphere of high-purity argon, raise the temperature to 110 °C and hold for 40 min to remove moisture and low-boiling-point impurities.

[0071] Take another 2 mL of octadecene and dry it at 110 °C for 30 min to obtain dried octadecene. Take 0.15 mmol (0.0606 g) of tris(dimethylamino)gallium dimer, 0.30 mmol (0.0919 g) of triphenylarsine and 2.0 mL of dried octadecene and dissolve them by sonication in a beaker to obtain a mixture; then put it into a syringe to prepare an injection solution.

[0072] 10 mL of octadecene in a three-necked flask was heated to 320 °C. Under these conditions, the mixture was injected into the three-necked flask at an injection rate of 0.4 mL / min, and the reaction was maintained at 320 °C for 30 min. After the reaction was completed, the mixture was allowed to cool naturally to room temperature, and then washed repeatedly with anhydrous ethanol and n-hexane to obtain Ga-GaAs nanomaterials.

[0073] 2. Photodetector manufacturing:

[0074] The Ga-GaAs nanomaterials prepared by the above method were uniformly spin-coated onto an n-type silicon wafer using a spin coater. A small portion of insulating tape was attached to one side of the sample on the n-type silicon wafer. A single layer of graphene of the same size as the silicon wafer was then tightly bonded to the upper surface of the sample. The lower n-type silicon wafer and the upper graphene layer served as two electrodes, forming a three-layer vertical structure to obtain a photodetector (specifically as shown in the image). Figure 8(As shown). The photoelectric performance of the detector was tested using a Keithley 2410 semiconductor test system.

[0075] 3. Sample testing:

[0076] (1) SEM, TEM, XRD, XPS tests

[0077] The composition and microstructure of the obtained Ga-GaAs products were analyzed.

[0078] Depend on Figures 1-2 The SEM and TEM images show that the prepared Ga-GaAs nanomaterials have good dispersion and a bulb-like structure. The ends are composed of elemental Ga, while the elongated tails, approximately 100 nm long, are GaAs. However, the material uniformity is not good because the concentration changes during the injection process are uneven, resulting in inconsistent lengths of the elongated GaAs tails grown in the system.

[0079] The obtained product was subjected to X-ray diffraction (XRD) testing, and the results are as follows: Figure 3 As shown. The obtained Ga-GaAs nanomaterial belongs to the F-43m space group and has a face-centered cubic structure. In the XRD pattern, the 2θ peaks located at 27.298°, 45.330°, 53.726°, 66.044° and 72.862° can be precisely corresponding to the (111), (220), (311), (400) and (331) diffraction planes of the material, respectively (JCPDS 01-080-0016). In addition, Ga elemental exists in the system, and a weak broad peak is observed between 35.34°, indicating that the Ga elemental crystallinity is very poor. Figure 3 The absence of any other impurity peaks indicates that the Ga-GaAs nanomaterials prepared by this invention are pure phases.

[0080] X-ray electron spectroscopy (XPS) such as Figure 4 As shown, where, Figure 4 In the image, 'a' represents the total XPS spectrum of the Ga-GaAs nanomaterial. Figure 4 In the image, b represents the fine spectrum of Ga 3d. Figure 4 In the image, c represents the fine spectrum of As 3d. Figure 4 In the fine 3d spectrum of Ga shown in Figure b, the characteristic peak of GaAs at a binding energy of 20.00 eV, the characteristic peak of elemental Ga at a binding energy of 18.00 eV, and the O 2s peak at a binding energy of 23.45 eV can be observed. The position of the O peak is due to the slight perturbation of external oxygen when the reaction source is injected into the system. Figure 4In the fine spectrum of As 3d shown in Figure c, two distinct peaks are observed at binding energies of 40.40 eV and 41.40 eV, respectively, confirming that arsenic has a valence state of -3. These results demonstrate the successful synthesis of Ga-GaAs nanomaterials with a swirl-like structure.

[0081] (2) HRTEM, HAADF-STEM, and characteristic absorption spectroscopy tests

[0082] like Figure 5 a and Figure 5 As shown in the high-resolution transmission electron microscopy (HRTEM) image in b, it can be seen that the 0.339 nm lattice spacing in the Ga-GaAs nanomaterial corresponds to the (111) crystal plane of GaAs. This indicates that the GaAs nanomaterial at the tail end has good crystallinity.

[0083] Figure 6 The high-angle annular dark-field image (HAADF-STEM) and mapping images of the two basic elements, Ga and As, verify that the head of the swirl-like structure is elemental Ga, while the tail (body) is composed of both Ga and As. This demonstrates that the reaction in this invention follows a self-catalyzed liquid-liquid-solid growth mechanism. After the reaction source is co-injected into the system, the gallium precursor source exhibits strong activity, first decomposing into nuclei to form elemental gallium. Subsequently, arsenic reacts with the gallium source at the active sites on the surface of the elemental gallium, ultimately forming the swirl-like nanostructure.

[0084] Figure 7 The image shows the characteristic absorption spectrum of the Ga-GaAs nanomaterial obtained in Example 1. Based on the slope, the band gap of the material can be calculated to be 1.47 eV, which is consistent with the 1.43 eV recorded in the prior art.

[0085] (3) Photoelectric response performance test

[0086] Figure 8 This is a schematic diagram of the photodetector fabricated in Example 1.

[0087] Figure 9 The photodetector obtained in Example 1 operates at a light intensity of 3 mW / cm². 2 The current-voltage (IV) curves for different wavelengths are shown below. It can be seen that the current is relatively small in darkness, while under illumination, the forward current increases rapidly, while the reverse current increases less, and the overall IV curve is nonlinear and asymmetrical. Under certain illumination conditions, the device exhibits good photoresponse to light of all wavelengths, with the strongest forward current response at 808 nm. This indicates that the device fabricated in this invention operates in diode mode and possesses a strong rectification effect.

[0088] Figure 10 The photodetector obtained in Example 1 operates at a light intensity of 3 mW / cm².2 The transient current response (It) curves for different wavelengths were obtained by controlling the illumination. It can be seen that when the light is on, the current increases rapidly and remains stable; after the power is turned off, the current quickly returns to its initial value. With a bias voltage of 2V, under certain illumination conditions, the device exhibits good light response to various wavelengths, especially under an 808nm light source with a light intensity of 3mW / cm². 2 The photocurrent was 0.118 mA, and the on / off ratio reached 31, which was stable and repeatable. These results indicate that the photodetector prepared in this invention has good response capability to near-infrared light.

[0089] Figure 11 The image shows the current-voltage (IV) curves of the photodetector obtained in Example 1 at different light intensities with a wavelength of 808 nm. It can be seen that the forward current increases rapidly with increasing light intensity, while the reverse current increases less. The photocurrent signal increases with increasing light intensity, indicating that the photocurrent is highly dependent on the light intensity. This is because the carrier concentration is positively correlated with the light intensity. Furthermore, the overall IV curve is nonlinear and asymmetrical, suggesting that the device fabricated in this invention operates in diode mode and has a strong rectification effect.

[0090] Figure 12 The image shows the transient current response (It) curves of the photodetector obtained in Example 1 at an 808nm wavelength, obtained by controlling the illumination to obtain different light intensities. It can be seen that when the light is on, the current increases rapidly and remains stable; after the power is turned off, the current quickly returns to its initial value. At a bias voltage of 2V, the photocurrent signal increases with increasing light intensity, reaching approximately 0.127mA, with a stable and repeatable on / off ratio of 30. These results indicate that the photodetector prepared in this invention has significant potential applications in the visible and near-infrared broadband detection fields.

[0091] Comparative Examples 1-3

[0092] 1. Sample preparation:

[0093] The preparation process was carried out according to Example 1, except that the injection rates were 4 mL / min, 1 mL / min, and 0.7 mL / min. A photodetector was prepared using the sample from Comparative Example 3 with an injection rate of 0.7 mL / min, and its photoelectric performance was tested.

[0094] 2. Sample testing:

[0095] The test samples and results are as follows: Figures 13-15 As shown. Figure 13 In Figure a, TEM image of Ga-GaAs nanomaterials obtained at an injection rate of 4 mL / min in Comparative Example 1 is shown, and XRD pattern of Ga-GaAs nanomaterials obtained in Figure b is shown. Figure 14 In Figure a, TEM image of Ga-GaAs nanomaterials obtained at an injection rate of 1 mL / min in Comparative Example 2 is shown, and XRD pattern of Ga-GaAs nanomaterials obtained in Figure b is shown. Figure 15 In Figure a, TEM image of Ga-GaAs nanomaterial obtained at an injection rate of 0.7 mL / min in Comparative Example 3 is shown. In Figure b, XRD pattern of Ga-GaAs nanomaterial is shown. In Figure c, transient current response It curves of photodetector prepared from Ga-GaAs nanomaterial at a wavelength of 808 nm are obtained by controlling the illumination to obtain different light intensities.

[0096] Depend on Figure 13 It can be seen that when the injection rate is 4 mL / min, there are very few ear-shaped morphological structures in the TEM image of a, and no obvious characteristic peaks of GaAs are found in the XRD image of b.

[0097] Depend on Figure 14 It can be seen that when the injection rate is 1 mL / min, a small number of ear-shaped morphological structures appear in the TEM image of a, and a relatively obvious characteristic peak of GaAs appears in the XRD image of b.

[0098] Depend on Figure 15 It can be seen that when the injection rate is 0.7 mL / min, the TEM image in a shows a more obvious bulbous morphology, and the product easily grows into a GaAs main body at the tail; the XRD image in b shows complete GaAs characteristic peaks, but impurities are still present in the system; the It curve in c shows that the detector responds to light of different intensities at a wavelength of 808 nm, but the photocurrent is lower than that in Example 1 at the same light intensity, and at a light intensity of 10 mW / cm². 2 The photocurrent is only 64μA.

[0099] Depend on Figures 13-15 It can be seen that for the prepared ear-shaped Ga-GaAs nanomaterials, the length of the tail / body gradually increases as the injection rate decreases. During the reaction, gallium is highly reactive and first forms elemental form, on which the GaAs body continues to grow. The faster the injection rate, the higher the initial average concentration of Ga source in the system, and the more difficult it is to grow the GaAs tail.

[0100] In fact, because arsenic sources have low reactivity while gallium sources have much higher reactivity, when the injection rate is too high, gallium forms amorphous elemental gallium under rapid supersaturation before the arsenic source has generated an active precursor, thus preventing the formation of GaAs. When the injection rate is too low, the gallium source in the mixture becomes more complexed with water in the external environment, reducing its activity and also preventing the formation of GaAs. Therefore, only at a suitable injection rate can Ga-GaAs nanomaterials be synthesized.

[0101] As can be seen from the above embodiments, the present invention provides a method for preparing Ga-GaAs nanomaterials, comprising the following steps: preparing tris(dimethylamino)gallium dimer C 12 H 36 Ga₂N₆ and triphenylarsine react in octadecene to obtain Ga-GaAs nanomaterials. The preparation method provided by this invention is a one-step process. Using a specific organic gallium source—tris(dimethylamino)gallium dimer and triphenylarsine—as precursors, the reaction sources are directly injected into a low-temperature liquid-phase system to synthesize highly dispersed Ga-GaAs nanomaterials with excellent photoelectric properties in an octadecene system. In the above reaction, all reaction sources are directly injected into the reaction system in one step, simplifying the operation and facilitating the synthesis of high-quality products. This invention also successfully constructed visible and near-infrared photodetectors with high response Ga-GaAs nanomaterials. The devices have simple structures, excellent performance, good stability and repeatability, and show great application potential in the visible and near-infrared bands.

[0102] The above description is only a preferred embodiment of the present invention. It should be noted that for those skilled in the art, several improvements and modifications can be made without departing from the principle of the present invention, and these improvements and modifications should also be considered within the scope of protection of the present invention.

Claims

1. A method for preparing Ga-GaAs nanomaterials, comprising the following steps: tris(dimethylamino)gallium dimer C 12 H 36 Ga2N6 and triphenylarsine are mixed in octadecene; the ratio of triphenylarsine to octadecene in the mixture is 0.30 mmol:(1~3) mL; the ratio of tri(dimethylamino)gallium dimer to octadecene is 0.15 mmol:(1~3) mL; The mixture was injected into octadecene at a rate of 0.4-0.5 mL / min to react and obtain Ga-GaAs nanomaterials; the reaction temperature was 300-330℃ and the time was 10-30 min. The volume ratio of octadecene to octadecene at 280~320℃ used in the preparation of the mixture is (1~3): (7~14); The Ga-GaAs nanomaterial has a bulb-like structure, with Ga as the element at the head and Ga and As distributed at the tail.

2. The method according to claim 1, characterized in that, The molar ratio of the tris(dimethylamino)gallium dimer to triphenylarsine is 0.15:(0.1~0.3); The volume ratio of octadecene to triphenylarsine was (10~15) mL : (0.1~0.3) mmol.

3. The preparation method according to claim 1, characterized in that, The reaction is carried out under protective gas conditions.

4. A Ga-GaAs nanomaterial prepared by the preparation method according to any one of claims 1 to 3.

5. A photodetector, prepared by the following method: Choose a suitable substrate as the base material; Choose a suitable conductive layer as the top layer material; The Ga-GaAs nanomaterial prepared by the preparation method described in claim 1 is used as an intermediate layer and coated onto the surface of a substrate to obtain a Ga-GaAs nanomaterial layer; a conductive layer is then deposited on the surface of the Ga-GaAs nanomaterial layer. A photodetector was obtained by using the bottom material and the top material as electrodes, respectively.

6. The photodetector according to claim 5, characterized in that, The substrate is selected from p-type silicon wafers, n-type silicon wafers, or FTO; The conductive layer is a single-layer graphene layer.

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