Ga-GaAs nano material, preparation method thereof and photoelectric detector

Abstract

The invention provides a Ga-GaAs nano material, a preparation method thereof and a photoelectric detector, and the preparation method comprises the following steps: carrying out a reaction on tri (dimethylamino) gallium dimer C12H36Ga2N6 and triphenylarsine in octadecene to obtain the Ga-GaAs nano material. The preparation method is a one-step method, a specific organic gallium source-tri (dimethylamino) gallium dimer and triphenylarsone are taken as precursors, a reaction source is directly injected into a low-temperature liquid phase system, and the Ga-GaAs nano material with the ear washing bulb-like structure, which is high in dispersion and excellent in photoelectric property, is synthesized in an octadecene system. In the reaction, all reaction sources are directly injected into a reaction system in one step, the operation is simple, and a high-quality product is easy to synthesize. The invention also successfully constructs a visible and near-infrared photoelectric detector of the Ga-GaAs nano material with high response, and the detector is simple in structure, excellent in performance, good in stability and repeatability, and has a great application prospect in visible and near-infrared bands.

Description

Technical Field

[0001] The invention belongs to the technical field of nanomaterials, and in particular relates to a Ga-GaAs nanomaterial and a preparation method thereof and a photoelectric detector. Background Art

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

[0003] Photodetectors are devices that can convert light signals into electrical signals. They play an important role in many fields. Photodetectors can be used in optical communications, laser radar, medical diagnosis, security monitoring, etc., improving the efficiency and accuracy of information transmission, scene perception, physiological monitoring and safety assurance. Summary of the invention

[0004] In view of this, the object of the present invention is to provide a Ga-GaAs nanomaterial and a preparation method thereof and a photoelectric detector. The method is a one-step method and can obtain a Ga-GaAs nanomaterial with high dispersibility and excellent photoelectric properties.

[0005] The present invention provides a method for preparing a Ga-GaAs nanomaterial, 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 tris(dimethylamino)gallium dimer to triphenylarsine is 0.15:(0.1-0.3);

[0008] The volume ratio of octadecene to triphenylarsine is (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 comprises:

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

[0013] The mixed solution is injected into octadecene at 280-320° C. 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 mixed solution is 0.30 mmol: (1-3) mL;

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

[0016] Preferably, the volume ratio of octadecene used in preparing the mixed solution to octadecene at 280-320° C. is (1-3):(7-14).

[0017] The present invention provides a Ga-GaAs nano material prepared by the preparation method described in the above technical solution.

[0018] The present invention provides a photoelectric detector, which is made by the following method:

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

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

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

[0022] The bottom layer material and the top layer material are used as electrodes respectively to obtain a photodetector.

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

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

[0025] The present invention provides a method for preparing Ga-GaAs nanomaterials, comprising the following steps: 12 H 36Ga2N6 and triphenylarsine react in octadecene to obtain Ga-GaAs nanomaterials. The preparation method provided by the present invention is a one-step method, using a specific organic gallium source-tri(dimethylamino)gallium dimer and triphenylarsine as precursors, and directly injecting the reaction source into a low-temperature liquid phase system to synthesize a highly dispersed, photoelectrically excellent Ga-GaAs nanomaterial with a quasi-earball structure in the octadecene system. In the above reaction, all reaction sources are directly injected into the reaction system in one step, which is simple to operate and easy to synthesize high-quality products. The present invention also successfully constructs a visible and near-infrared photodetector with a highly responsive Ga-GaAs nanomaterial, the device has a simple structure, excellent performance, good stability and repeatability, and has great application prospects in the visible and near-infrared bands. BRIEF DESCRIPTION OF THE DRAWINGS

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

[0027] Figure 2 This is a TEM test image of the Ga-GaAs nanomaterial obtained in Example 1 of the present invention;

[0028] Figure 3 This is the XRD pattern of the Ga-GaAs nanomaterial obtained in Example 1 of the present invention;

[0029] Figure 4 This is the XPS graph of the Ga-GaAs nanomaterial obtained in Example 1 of the present invention; wherein, Figure 4 a is the XPS total 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 This is the HRTEM image of the Ga-GaAs nanomaterial obtained in Example 1 of the present invention; Figure 5 a is the HRTEM image of Ga-GaAs nanomaterials. Figure 5 b is the selected area calibration diagram of Ga-GaAs nanomaterials;

[0031] Figure 6 The high-angle annular dark field image (HAADF-STEM) of the Ga-GaAs nanomaterial obtained in Example 1 of the present invention and the mapping diagram of the two basic elements Ga and As; wherein, Figure 6 The middle a is a high-angle annular dark field image. Figure 6 Where b is the Mapping diagram of the As element. Figure 6 Where c is the mapping diagram of Ga element. Figure 6 Figure d in the figure is the distribution diagram of Ga and As elements in the high-angle annular dark field image;

[0032] Figure 7 This is a characteristic absorption spectrum of the Ga-GaAs nanomaterial obtained in Example 1 of the present invention;

[0033] Figure 8 is a schematic diagram of the structure of the photodetector prepared in Example 1 of the present invention;

[0034] Fig. 9 The photodetector obtained in Example 1 of the present invention has a light intensity of 3 mW / cm 2 The current-voltage (IV) curves at different wavelengths are shown below;

[0035] Fig.10 The photodetector obtained in Example 1 of the present invention has a light intensity of 3 mW / cm 2 Under the condition of light, the current transient response It curves of different wavelengths are obtained by controlling the light;

[0036] Fig.11 The current-voltage (IV) curve of the photodetector obtained in Example 1 of the present invention at different light intensities at a wavelength of 808 nm;

[0037] Fig.12 The photodetector obtained in Example 1 of the present invention is a current transient response It curve diagram of different light intensities obtained by controlling light illumination at a wavelength of 808 nm;

[0038] Fig.13 Characterization diagram of Ga-GaAs nanomaterial obtained at an injection rate of 4 mL / min in Comparative Example 1 of the present invention; wherein a is a TEM test diagram of the obtained Ga-GaAs nanomaterial, and b is an XRD diagram of the obtained Ga-GaAs nanomaterial;

[0039] Fig.14 Characterization diagram of Ga-GaAs nanomaterial obtained at an injection rate of 1 mL / min in Comparative Example 2 of the present invention; wherein a is a TEM test diagram of the obtained Ga-GaAs nanomaterial, and b is an XRD diagram of the obtained Ga-GaAs nanomaterial;

[0040] Fig.15 This is a characterization diagram of the Ga-GaAs nanomaterial obtained in comparative example 3 of the present invention at an injection rate of 0.7 mL / min; wherein, a is a TEM test diagram of the obtained Ga-GaAs nanomaterial, b is an XRD diagram of the obtained Ga-GaAs nanomaterial, and c is a current transient response It curve diagram of the photodetector prepared from the obtained Ga-GaAs nanomaterial at a light wavelength of 808 nm, obtained by controlling the light illumination at different light intensities. DETAILED DESCRIPTION

[0041] The present invention provides a method for preparing a Ga-GaAs nanomaterial, 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 the present 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] The molar ratio of the volume of octadecene to triphenylarsine in the present invention is (10-15) mL: (0.1-0.3) mmol, preferably (10-12) mL: (0.1-0.3) mmol. In a specific embodiment, the molar ratio of the volume of octadecene to triphenylarsine is 10 mL: (0.1-0.3) mmol.

[0045] The above preparation method specifically comprises:

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

[0047] The mixed solution is injected into octadecene at 280-320° C. at a rate of 0.4-0.5 mL / min to react and obtain Ga-GaAs nanomaterials.

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

[0049] The ratio of triphenylarsine to octadecene in the mixed solution of the present invention 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 the present invention, the reaction is carried out under protective gas conditions; the present invention has no particular limitation on the type of the protective gas, and it can be any conventional protective gas known to those skilled in the art, such as nitrogen or argon. The present invention has no particular limitation on the gas pressure of the reaction, and it can be normal pressure.

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

[0052] In the present invention, the low-cost, stable arsenic source has low reaction activity, and the gallium source is extremely active and easily oxidized, so the two need to be made into a mixed solution and injected into the system together. On the one hand, if only the solution-liquid-solid reaction mechanism is considered, it is generally necessary to quickly inject the mixed solution to supersaturate the reactant precursor source, generate activity, and thus grow crystals. But in fact, if the mixed solution is quickly injected into the system, the highly active gallium source will react quickly to generate gallium monomer before the low-activity arsenic source has become active, thereby losing its activity and being unable to react with the arsenic source. On the other hand, in order to increase the activity of the low-activity arsenic source so that it reacts, the reaction temperature needs to be increased. But at the same time, the highly active gallium source will also be more active and easier to generate gallium monomer. Therefore, it is necessary to consider the appropriate injection rate and temperature to balance the active coexistence state of the high-activity gallium source and the low-activity arsenic source in the system, so as to generate the desired gallium arsenide nanomaterial.

[0053] The present invention injects the mixed solution into octadecene at 280 to 320° C. at a rate of 0.4 to 0.5 mL / min for reaction to obtain Ga-GaAs nanomaterials. When the injection rate is 4 mL / min, basically no GaAs tail is generated. As the injection rate slows down, the tail GaAs gradually becomes longer, the crystallinity and quality gradually improve, and the photoelectric performance is improved. When the injection rate is 0.4 mL / min, a Ga-GaAs nanomaterial with a highly dispersed, photoelectrically excellent structure similar to an ear ball can be obtained. As the injection rate continues to slow down, the degree of complexation between the gallium source in the mixed solution and the water in the external environment increases, which is not conducive to the reaction. Therefore, the injection rate of the present invention is 0.4-0.5 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 the present invention, tris(dimethylamino)gallium dimer C 12 H 36 The temperature of the reaction of Ga2N6 and triphenylarsine in octadecene is 300-330°C and the time is 10-30 minutes. In a specific embodiment, the reaction temperature is 320°C and the time is 30 minutes.

[0055] The volume ratio of octadecene used in the mixed solution to octadecene at 280-320° C. is (1-3):(7-14). In a specific embodiment, the volume ratio of octadecene used in the mixed solution to octadecene at 320° C. is 2:10.

[0056] The present invention preferably performs 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; and the product is washed repeatedly.

[0057] Compared with other vapor phase growth methods, the low-temperature one-step method of the present invention greatly reduces the reaction temperature and time, is easy to operate, and high-quality products are easy to synthesize, and can be used for large-scale applications in actual production.

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

[0059] In order to prove that Ga-GaAs nanomaterials have photoelectric response performance, the present invention also provides a photoelectric detector, which is prepared according to the following method:

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

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

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

[0063] The bottom layer material and the top layer material are used as electrodes respectively to obtain a photodetector.

[0064] In the present invention, the substrate is selected from a p-type silicon wafer, an n-type silicon wafer or FTO; and the conductive layer is a single-layer graphene layer.

[0065] In a specific embodiment, the substrate is an n-type silicon wafer, the conductive layer is a single-layer graphene layer, the Ga-GaAs nanomaterial prepared by the above method is evenly spin-coated on the n-type silicon wafer by a coating machine, a small portion of insulating tape is attached to one side of the sample on the n-type silicon wafer, and the graphene of the same size as the silicon wafer is closely attached to the upper surface of the sample, and the lower n-type silicon wafer and the upper graphene are used as two electrodes to form a three-layer vertical structure to obtain a photodetector (specifically, Figure 8 shown).

[0066] The preparation method provided by the present invention is a one-step method, using a specific organic gallium source-tri(dimethylamino)gallium dimer and triphenylarsine as precursors, and directly injecting the reaction source into a low-temperature liquid phase system to synthesize a highly dispersed, photoelectrically excellent Ga-GaAs nanomaterial with a quasi-earball structure in an octadecene system. In the above reaction, all reaction sources are directly injected into the reaction system in one step, which is simple to operate and easy to synthesize high-quality products. The present invention also successfully constructs a visible and near-infrared photodetector with a highly responsive Ga-GaAs nanomaterial, the device has a simple structure, excellent performance, good stability and repeatability, and has great application prospects in the visible and near-infrared bands.

[0067] In order to further illustrate the present invention, a Ga-GaAs nanomaterial, a preparation method thereof and a photoelectric detector provided by the present invention are described in detail below in conjunction with embodiments, but they should not be construed as limiting the scope of protection of the present invention.

[0068] Example 1

[0069] 1. Sample preparation:

[0070] 10 mL of octadecene was added into a 100 mL three-necked flask, and the temperature was raised to 110° C. and kept for 40 min under stirring with a high-temperature stirring magnet in a reaction atmosphere of high-purity argon to remove moisture and low-boiling impurities.

[0071] Another 2 mL of octadecene was taken and dried at 110°C for 30 min to obtain dry octadecene. 0.15 mmol (0.0606 g) of tris(dimethylamino)gallium dimer, 0.30 mmol (0.0919 g) of triphenylarsine and 2.0 mL of dry octadecene were placed in a beaker and ultrasonically dissolved to obtain a mixed solution; then the mixed solution was placed in a syringe to prepare an injection liquid.

[0072] The temperature of 10 mL of octadecene in a three-necked flask was raised to 320°C. Under this condition, the mixed solution was injected into the three-necked flask at an injection rate of 0.4 mL / min and kept at 320°C for 30 minutes. After the reaction was completed, it was naturally cooled to room temperature, and then repeatedly washed with anhydrous ethanol and n-hexane to obtain Ga-GaAs nanomaterials.

[0073] 2. Photodetector manufacturing:

[0074] The Ga-GaAs nanomaterial prepared by the above method is evenly spin-coated on an n-type silicon wafer by a coating machine, a small portion of insulating tape is attached to one side of the sample on the n-type silicon wafer, a single-layer graphene of the same size as the silicon wafer is tightly attached to the upper surface of the sample, and the lower n-type silicon wafer and the upper graphene are used as two electrodes to form a three-layer vertical structure to obtain a photodetector (specifically, Figure 8The photoelectric performance of the detector was tested using a Keithley 2410 semiconductor test system.

[0075] 3. Sample testing:

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

[0077] The component composition and micromorphology of the obtained Ga-GaAs product were analyzed.

[0078] Depend on Figures 1-2 From the SEM and TEM test images, we can see that the prepared Ga-GaAs nanomaterials have good dispersion and a structure similar to a spherical shape. The tip is Ga and the elongated tail of about 100nm is GaAs. However, the material uniformity is not good enough because the concentration of the substance changes unevenly during the injection process, and the elongated tails of GaAs grown in the system vary in length.

[0079] The obtained product was subjected to X-ray diffraction (XRD) test, and the results were 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 graph, the 2θ peaks at 27.298°, 45.330°, 53.726°, 66.044° and 72.862° can accurately correspond to the (111), (220), (311), (400) and (331) diffraction crystal planes of the material, respectively (JCPDS 01-080-0016). In addition, Ga single substance exists in the system, and a weak broad peak is observed between 35.34°, indicating that the crystallinity of Ga single substance is very poor. Figure 3 There are no other impurity peaks, indicating that the Ga-GaAs nanomaterial prepared by the present invention is pure phase.

[0080] X-ray electron spectroscopy (XPS) Figure 4 As shown, Figure 4 a in the figure is the XPS total spectrum of Ga-GaAs nanomaterials. Figure 4 b is the fine spectrum of Ga 3d. Figure 4 In the figure c is the fine spectrum of As 3d. Figure 4 In the Ga 3d fine spectrum shown in (b), the characteristic peak of GaAs at 20.00 eV binding energy, the characteristic peak of Ga element at 18.00 eV binding energy, and the O 2s peak at 23.45 eV binding energy can be observed. The peak position of O is 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 c, there are two obvious peaks at binding energies of 40.40 eV and 41.40 eV, proving that the valence state of arsenic is -3. The above results illustrate the successful synthesis of Ga-GaAs nanomaterials with a quasi-silicon sphere structure.

[0081] (2) HRTEM, HAADF-STEM, characteristic absorption spectrum test

[0082] like Figure 5 A and Figure 5 As shown in the high-resolution transmission electron micrograph (HRTEM) in middle b, it can be seen that the lattice spacing of 0.339 nm in the Ga-GaAs nanomaterial corresponds to the (111) crystal plane of GaAs, indicating that the crystallinity of the tail GaAs nanomaterial is good.

[0083] Figure 6 The high-angle annular dark field image (HAADF-STEM) of the obtained product and the mapping diagram of the two basic elements Ga and As verify that the head of the ear-washing spherical structure is a single Ga element, and the tail (trunk body) is a distribution of two elements Ga and As. The above proves that the reaction of the present invention follows the self-catalytic liquid-liquid-solid growth mechanism. After the reaction sources are co-injected into the system, the gallium precursor source is highly active and first decomposes into nuclei to form a single gallium substance. Then, arsenic reacts with the gallium source at the surface active sites of the single gallium substance to finally form an ear-washing spherical nanostructure.

[0084] Figure 7 This is the characteristic absorption spectrum of the Ga-GaAs nanomaterial obtained in Example 1; based on the slope, it can be inferred that the band gap of the material is 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 It is a schematic diagram of the structure of the photodetector prepared in Example 1.

[0087] Fig. 9 The photodetector obtained in Example 1 has a light intensity of 3 mW / cm 2 The current-voltage (IV) curves of different wavelengths are shown below. It can be seen that the current is small under dark conditions, and under light conditions, the forward current increases rapidly, the reverse current increases less, and the overall IV curve is nonlinear and asymmetric; under certain light conditions, the device has a good light response to light of each wavelength, and the forward current response is strongest at 808nm wavelength. This shows that the device prepared by the present invention works in diode mode and has a strong rectification effect.

[0088] Fig.10 The photodetector obtained in Example 1 has a light intensity of 3 mW / cm2 Under the condition of 2V bias, under certain illumination conditions, the device has good light response to light of all wavelengths, especially under 808nm light source, when the light intensity is 3mW / cm 2 The photocurrent is 0.118 mA, and the on / off ratio can reach 31 and is stable and repeatable. These results show that the photodetector prepared by the present invention has good response ability to near-infrared light.

[0089] Fig.11 The current-voltage (IV) curve of the photodetector obtained in Example 1 at different light intensities at a wavelength of 808 nm is shown. It can be seen that as the light intensity increases, the forward current increases rapidly, and the reverse current increases less. The photocurrent signal increases with the increase in light intensity, indicating that the photocurrent has a great dependence on the light intensity, because the concentration of carriers is positively correlated with the light intensity, and the overall IV curve is nonlinear and asymmetric, which shows that the device prepared by the present invention works in diode mode and has a strong rectification effect.

[0090] Fig.12 The photodetector obtained in Example 1 is a current transient response It curve diagram of different light intensities obtained by controlling the light illumination at a light wavelength of 808nm. 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 the initial value; when the bias voltage is 2V, the photocurrent signal increases with the increase of light intensity, and the photocurrent can reach about 0.127mA. The on-off ratio can reach 30 and is stable and repeatable. These results show that the photodetector prepared by the present invention has great potential applications in the field of visible and near-infrared wide-spectrum detection.

[0091] Comparative Examples 1 to 3

[0092] 1. Sample preparation:

[0093] The preparation process of Example 1 was followed, except that the injection rates were 4 mL / min, 1 mL / min, and 0.7 mL / min. The sample of Comparative Example 3 with an injection rate of 0.7 mL / min was used to prepare a photoelectric detector, and the photoelectric performance was tested.

[0094] 2. Sample testing:

[0095] The test samples were tested and the results were as follows Figures 13-15 shown. Fig.13 a is a TEM image of the Ga-GaAs nanomaterial obtained in Comparative Example 1 at an injection rate of 4 mL / min, and b is an XRD image of the Ga-GaAs nanomaterial obtained; Fig.14 a is a TEM image of the Ga-GaAs nanomaterial obtained in Comparative Example 2 at an injection rate of 1 mL / min, and b is an XRD image of the Ga-GaAs nanomaterial obtained; Fig.15 In the figure, a is the TEM image of the Ga-GaAs nanomaterial obtained in comparative example 3 with an injection rate of 0.7 mL / min, b is the XRD image of the Ga-GaAs nanomaterial obtained, and c is the current transient response It curve of the photodetector prepared from the Ga-GaAs nanomaterial at different light intensities obtained by controlling the light at a light wavelength of 808 nm.

[0096] Depend on Fig.13 It can be seen that when the injection rate is 4 mL / min, there are only very few ear-washing ball-like structures in the TEM image in a, and there is no obvious characteristic peak of GaAs in the XRD image in b.

[0097] Depend on Fig.14 It can be seen that when the injection rate is 1 mL / min, a small amount of ear-washing ball-like morphology structures appear in the TEM image in a, and a more obvious characteristic peak of GaAs appears in the XRD image in b.

[0098] Depend on Fig.15 It can be seen that when the injection rate is 0.7 mL / min, more obvious ear-washing ball-like morphology structures appear in the TEM image in a, and the product easily grows a tail GaAs body; a complete GaAs characteristic peak appears in the XRD image in b, but impurities still exist in the system; the It curve in c shows that the detector responds to light of different light intensities at a wavelength of 808 nm, but the photocurrent is lower than that of Example 1 at the same light intensity. 2 The photocurrent is only 64μA.

[0099] Depend on Figures 13-15 It can be seen that for the prepared ear-washing spherical Ga-GaAs nanomaterial, as the injection rate slows down, the length of the tail / trunk body gradually becomes longer. During the reaction process, gallium is highly active and generates a single substance first, and then the GaAs body continues to grow on the gallium single substance. The faster the injection rate, the greater the initial average concentration of the system Ga source, and the more difficult it is to grow the GaAs tail.

[0100] In fact, because the arsenic source has low reactivity and the gallium source has much higher reactivity than the arsenic source, when the injection rate is too high, before the arsenic source produces active precursors, gallium forms amorphous gallium under rapid supersaturation, and GaAs cannot be formed. When the injection rate is too low, the gallium source in the mixed solution increases the degree of complexation with water in the external environment, the gallium source activity decreases, and GaAs cannot be generated. Therefore, Ga-GaAs nanomaterials can only be synthesized at a suitable injection rate.

[0101] From the above embodiments, it can be seen that the present invention provides a method for preparing Ga-GaAs nanomaterials, comprising the following steps: 12 H 36 Ga2N6 and triphenylarsine react in octadecene to obtain Ga-GaAs nanomaterials. The preparation method provided by the present invention is a one-step method, using a specific organic gallium source-tri(dimethylamino)gallium dimer and triphenylarsine as precursors, and directly injecting the reaction source into a low-temperature liquid phase system to synthesize a highly dispersed, photoelectrically excellent Ga-GaAs nanomaterial with a quasi-earball structure in the octadecene system. In the above reaction, all reaction sources are directly injected into the reaction system in one step, which is simple to operate and easy to synthesize high-quality products. The present invention also successfully constructs a visible and near-infrared photodetector with a highly responsive Ga-GaAs nanomaterial, the device has a simple structure, excellent performance, good stability and repeatability, and has great application prospects in the visible and near-infrared bands.

[0102] The above is only a preferred embodiment of the present invention. It should be pointed out that for ordinary technicians in this technical field, several improvements and modifications can be made without departing from the principle of the present invention. These improvements and modifications should also be regarded as the scope of protection of the present invention.

Claims

1. A method for preparing a Ga-GaAs nanomaterial, comprising the following steps: Tris(dimethylamino)gallium dimer C 12 H 36 Ga2N6 and triphenylarsine react in octadecene to obtain Ga-GaAs nanomaterials.

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 is (10-15) mL: (0.1-0.3) mmol.

3. The method according to claim 1, characterized in that The reaction temperature is 300-330°C and the reaction time is 10-30 minutes.

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

5. The preparation method according to claim 1, characterized in that: The preparation method specifically comprises: Tris(dimethylamino)gallium dimer C 12 H 36 Ga2N6 and triphenylarsine form a mixed solution in octadecene; The mixed solution is injected into octadecene at 280-320° C. at a rate of 0.4-0.5 mL / min to react and obtain Ga-GaAs nanomaterials.

6. The preparation method according to claim 5, characterized in that: The ratio of triphenylarsine to octadecene in the mixed solution is 0.30 mmol: (1-3) mL; The usage ratio of tri(dimethylamino)gallium dimer to octadecene is 0.15mmol:(1-3)mL.

7. The preparation method according to claim 5, characterized in that: The volume ratio of octadecene used in preparing the mixed solution to octadecene at 280-320° C. is (1-3):(7-14).

8. A Ga-GaAs nanomaterial prepared by the preparation method according to any one of claims 1 to 7.

9. A photodetector, made by the following method: Choose a suitable substrate as the base material; Select a suitable conductive layer as the top material; The Ga-GaAs nanomaterial prepared by the preparation method of claim 1 is used as an intermediate layer and coated on the surface of the substrate to obtain a Ga-GaAs nanomaterial layer; a conductive layer is laid on the surface of the Ga-GaAs nanomaterial layer; The bottom layer material and the top layer material are used as electrodes respectively to obtain a photodetector.

10. The photodetector according to claim 9, characterized in that: The substrate is selected from a p-type silicon wafer, an n-type silicon wafer or FTO; The conductive layer is a single-layer graphene layer.

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