阅读说明：本技术 一种利用Sn纳米线作为模板引导生长CdS分支结构及其催化生长方法和应用 (CdS branch structure guided and grown by using Sn nanowire as template and catalytic growth method and application thereof ) 是由 张黎 韩晓宁 文沛婷 邹炳锁 李京波 于 2021-07-30 设计创作，主要内容包括：本发明属于半导体光电纳米材料制备技术领域,公开了一种利用Sn纳米线作为模板引导生长CdS分支结构的催化生长方法。该方法是将CdS固体粉末和SnO-(2)粉末研磨并混合均匀,得到前驱体混合粉末；将前驱体混合粉末倒入瓷舟中,置于管式炉的中心加热温区位置,将预处理的云母片衬底置于距中心加热温区11～12cm处的下游沉积区的瓷舟上,将瓷舟均置于石英管内,通入氢气和氩气的混合气体,将石英管内的空气排净后,在850～1150℃温度下反应,加热过程中,气流速率保持为20～40sccm,反应结束后自然降至室温,在石英管内壁和云母衬底上得到Sn掺杂CdS分支结构。该方法不需要辅助条件,通过调节合成参数一步生长得到。(The invention belongs to the technical field of semiconductor photoelectric nano material preparation, and discloses a catalytic growth method for guiding a CdS branch structure to grow by using Sn nanowires as templates. The method is to mix CdS solid powder and SnO 2 Grinding the powder and uniformly mixing to obtain precursor mixed powder; pouring the precursor mixed powder intoPlacing the ceramic boat in a central heating temperature zone of a tube furnace, placing a pretreated mica sheet substrate on the ceramic boat in a downstream deposition zone 11-12 cm away from the central heating temperature zone, placing the ceramic boats in a quartz tube, introducing a mixed gas of hydrogen and argon, completely exhausting air in the quartz tube, reacting at 850-1150 ℃, keeping the air flow rate at 20-40 sccm in the heating process, naturally cooling to room temperature after the reaction is finished, and obtaining a Sn-doped CdS branch structure on the inner wall of the quartz tube and the mica substrate. The method does not need auxiliary conditions and is obtained by one-step growth by adjusting synthesis parameters.)

1. A catalytic growth method for guiding a CdS branch structure to grow by using Sn nanowires as templates is characterized by comprising the following specific steps of:

s1, mixing CdS solid powder and SnO₂Grinding the powder and uniformly mixing to obtain precursor mixed powder;

s2, ultrasonically cleaning the mica substrate with acetone, ethanol and deionized water respectively, and then blow-drying with a nitrogen gun to obtain a pretreated mica sheet substrate;

s3, pouring the precursor mixed powder obtained in the step 1 into a porcelain boat, placing the porcelain boat at a central heating temperature area of a tube furnace, placing the pretreated mica sheet substrate on the porcelain boat in a downstream deposition area 11-12 cm away from the central heating temperature area, placing the porcelain boats in a quartz tube, introducing mixed gas of hydrogen and argon, discharging air in the quartz tube, reacting at 850-1150 ℃, keeping the airflow rate at 20-40 sccm in the heating process, depositing Sn nanowires on the pretreated mica sheet substrate, naturally cooling to room temperature after the reaction is finished, and obtaining the Sn-doped CdS branch structure on the inner wall of the quartz tube and the mica substrate.

2. The catalytic growth method of guiding growing CdS branch structure using Sn nanowire as template as claimed in claim 1, wherein CdS solid powder and SnO as described in step S1₂The mass ratio of the powder is (5-20): 1.

3. The catalytic growth method for guiding the growth of the CdS branched structure by using Sn nanowires as templates as claimed in claim 1, wherein the cleaning time in step S2 is 10-20 min.

4. The catalytic growth method for guided growth of CdS branched structure using Sn nanowire as template in claim 1, wherein the volume ratio of hydrogen to argon in step S3 is (5-12): (95-88).

5. The catalytic growth method for guiding the growth of the CdS branched structure by using Sn nanowires as templates as claimed in claim 1, wherein the exhaust rate in step S3 is 20-40 sccm; the exhaust time is 1-2 h.

6. The catalytic growth method for guiding the growth of the CdS branch structure by using Sn nanowires as templates as claimed in claim 1, wherein the heating rate in step S3 is 40-100 ℃/min; the reaction time is 20-120 min.

7. A Sn doped CdS branched structure, characterized in that it is prepared by the method of any one of claims 1-6.

8. The Sn-doped CdS branch structure according to claim 7, wherein the Sn-doped CdS branch structure is a comb-shaped structure, a leaf-shaped branch structure, or a cone-shaped branch structure.

9. The Sn-doped CdS branch structure according to claim 7, wherein the Sn-doped CdS branch structure has a diameter size of 300nm to 5 μm.

10. Use of a Sn-doped CdS branched structure as defined in any one of claims 7 to 9 in the field of optical waveguide or electrical transport.

Technical Field

The invention belongs to the technical field of semiconductor photoelectric nano material preparation, and particularly relates to a CdS branch structure guided by using an Sn nanowire as a template and a catalytic growth method and application thereof.

Background

CdS is an important member of II-VI group semiconductors, has a wider band gap (2.42 eV at room temperature), is a direct band gap, has larger exciton binding energy, has strong polarity and has wide application range. Meanwhile, CdS is a typical wurtzite structure semiconductor and is an excellent optical microcavity template material. The preparation method is simple, the confinement effect is obvious, the electronic structure is simple, and the CdS micro/nano material becomes a semiconductor material concerned with a plurality of nano-scale photoelectric properties, thereby promoting the progress of the nano technology to a certain extent. Among them, in the structures with different dimensions such as nanocrystalline, nano-wire and nano-sheet, many new physical properties caused by quantum confinement are generated, the cognition of people on the application of physical phase and physical property is expanded, and numerous new applications are opened up.

The branched structure has a multi-branched networked nano-structure system, which is regarded as one of available modules for constructing a complex nano photoelectric device capable of being used and arrayed as a set of one-dimensional nanowires, and has huge application potential and receives wide attention. The branched or tree-shaped network nano structure is a complex micro-nano structure with one or more sub-branched nano wires growing on a main nano wire. Due to the appearance of the branch structure, compared with a micro-nano structure with higher dimensionality accessed in the construction process of a micro-nano device, the micro-nano structure with higher dimensionality is formed by spontaneous growth in the chemical preparation process of the micro-nano device, has higher crystallinity, can well realize parallel access and interconnection at the branch structure and the main part, simultaneously realizes enhancement and regulation and control of the nano linear performance, and is a special nano structure with research value. Because of this, the related research on the specific structure of the multi-branched nano-structure, such as comb array, four-foot cone, etc., has become a more popular subject in recent years, and many international subject groups have developed similar research. However, the synthesis of the branch structure usually requires a complex method, step-by-step, microwave-assisted method, etc., and the steps are complex and time-consuming, and the loss-free and efficient transmission of photons in the branch structure and the electrical performance are affected by the unclean surface and the poor quality of crystal lattices.

Disclosure of Invention

In order to overcome the defects and shortcomings of the prior art, the invention aims to provide a catalytic growth method for guiding a CdS branch structure to grow by using a Sn nanowire as a template.

The purpose of the invention is realized by the following technical scheme:

a catalytic growth method for guiding a CdS branch structure to grow by using Sn nanowires as templates comprises the following specific steps:

s1, mixing CdS solid powder and SnO₂Grinding the powder and uniformly mixing to obtain precursor mixed powder;

s2, ultrasonically cleaning the mica substrate with acetone, ethanol and deionized water respectively, and then blow-drying with a nitrogen gun to obtain a pretreated mica sheet substrate;

s3, pouring the precursor mixed powder obtained in the step 1 into a porcelain boat, placing the porcelain boat at a central heating temperature area of a tube furnace, placing the pretreated mica sheet substrate on the porcelain boat in a downstream deposition area 11-12 cm away from the central heating temperature area, placing the porcelain boats in a quartz tube, introducing mixed gas of hydrogen and argon, discharging air in the quartz tube, reacting at 850-1150 ℃, keeping the airflow rate at 20-40 sccm in the heating process, depositing Sn nanowires on the pretreated mica sheet substrate, naturally cooling to room temperature after the reaction is finished, and obtaining the Sn-doped CdS branch structure on the inner wall of the quartz tube and the mica substrate.

Preferably, the CdS solid powder and SnO described in step S1₂The mass ratio of the powder is (5-20): 1.

preferably, the cleaning time in the step S2 is 10-20 min.

Preferably, the volume ratio of the hydrogen to the argon in the step S3 is (5-12): 95-88.

Preferably, the exhaust rate in the step S3 is 20-40 sccm; the exhaust time is 1-2 h.

Preferably, the heating rate in the step S3 is 40-100 ℃/min; the reaction time is 20-120 min.

More preferably, in the step S3, the reaction temperature is 950-1050 ℃, and the heating rate is 50-90 ℃/min; the reaction time is 30-90 min.

The Sn doped CdS branch structure is prepared by the method.

Preferably, the Sn-doped CdS branch structure is a comb-shaped structure, a leaf-shaped branch structure, or a tapered branch structure;

preferably, the diameter size of the Sn doped CdS branched structure is 300 nm-5 μm.

The Sn doped CdS branch structure is applied to the field of optical waveguide or electrical transportation.

The preparation method comprises the following steps: CVD growing SnO₂Preparing and uniformly mixing the CdS precursor powder and CdS precursor powder; cleaning and blow-drying pretreatment of the silicon/mica substrate; adjusting parameters in the growth process, including growth time, reaction temperature, heating rate, proportion of precursor powder, content of hydrogen in mixed gas and the like; and fourthly, catalyzing and growing the template with the CdS branch structure. The branched structure obtained by the method has smooth and clean surface, higher lattice quality, diameter size of 300 nm-5 mu m, length of 300-1500 mu m, uniform shape and adjustable appearance under growth parameters. Sn dopingThe principle of the growth process of the heteroCdS branched structure is shown in FIG. 1.

SnO₂And reacting the mixed powder with CdS in a quartz tube at 850-1150 ℃ by using argon-hydrogen mixed gas. (a) Firstly, Sn gas (the melting point of Sn is 232 ℃) is formed, and with the transportation of the introduced argon-hydrogen mixed gas to the downstream low-temperature region of the quartz tube, droplets or clusters of Sn metal are formed on the pretreated mica sheet substrate, and with the progress of reaction, Sn balls are further formed through deposition, and the Sn nano wires are formed through the Sn balls formed through deposition. (b) With a rapid increase of the growth temperature (-100 ℃/min), the growth rate was increased by the reaction: CdS + H₂→Cd+H₂And S. The mixed Sn and Cd gases, the sublimated CdS gas, will also follow the argon-hydrogen mixture gas to the low temperature region (deposition region). The Cd and Sn form alloy on the surface of the Sn nanowire, and then sublimed CdS gas and Cd and H₂And S reacts to form CdS which are deposited on the alloy surface of the Sn nanowire, and a shell-core layer of the CdS is formed on the alloy transition layer of the Sn nanowire to obtain the Sn nanowire with the CdS shell-core structure. Excess hydrogen to SnO₂The hydrogen gas and the water vapor are changed into the water vapor and the Sn gas, the generation of the CdS gas is promoted, the oxygen gas can be combined with the hydrogen gas to form the water vapor, and the water vapor is discharged out of the quartz tube along with the continuously introduced argon-hydrogen mixed gas. (c) And meanwhile, the Sn nanowire is broken in the process of generating the Sn nanowire with the CdS shell-core structure, and because Sn gas is not completely consumed, Sn is deposited on the CdS surface of the Sn nanowire with the CdS shell-core structure to form new liquid drops or clusters, and the deposited Sn provides new adsorption growth sites for the CdS nanowire. With further extension of the reaction time, owing to SnO₂The content of the precursor powder is far less than that of CdS powder (SnO)₂The mass ratio of the Sn to the CdS is 1: 5-20), and the deposited Sn can not keep the original valence state. (d) The Sn nanowire of the core portion will liquefy under heating, and since the liquid is very unstable at high temperature, a part of Sn balls will be precipitated from the Sn nanowire of the core portion on the nanowire trunk. (e) And finally, after a relatively long reaction time (about 60 min), preparing a Sn doped CdS branch structure at a new adsorption growth site.

Compared with the prior art, the invention has the following beneficial effects:

1. according to the method, the morphology of the branch structure is effectively and controllably adjusted through growth parameters, and in the synthesis process, Sn metal is used not only as a catalyst, but also as a template, and the Sn-doped CdS branch structure is obtained through growth. Different from the traditional growth method, the method does not need auxiliary conditions, can obtain the high-quality CdS branch structure by one-step growth through adjusting synthesis parameters, greatly saves the synthesis cost and time, and has innovation in the field of low-dimensional semiconductor synthesis.

2. The Sn doped CdS crystal lattice prepared by the method has the advantages of less vacancy and other defects, higher crystal lattice quality, clean and smooth surface, excellent optical property and remarkable optical waveguide performance.

Drawings

FIG. 1 is a schematic diagram of the growth process of a Sn doped CdS branched structure of the present invention.

FIG. 2 is an SEM photograph of a branched structure and a comb-like structure of the Sn-doped CdS array prepared in example 1;

FIG. 3 is a fluorescence plot of Sn doped CdS array branch structure prepared in example 1, with microscope images corresponding thereto;

FIG. 4 is a temperature dependent fluorescence spectrum of the Sn doped CdS comb-like structure prepared in example 1.

FIG. 5 is an SEM photograph of a Sn doped CdS lobed branched structure prepared in example 2;

FIG. 6 is an SEM photograph of the branched structure of the Sn-doped CdS cone-shaped trunk prepared in example 3;

fig. 7 is a microscope image of Sn-doped CdS branch structure prepared in example 4, in which Sn metal balls are present in the branches during the formation process.

Fig. 8 is a microscope photograph of an optical waveguide of the Sn-doped CdS comb structure prepared in example 5, with corresponding optical microscope images being shown in inset.

Detailed Description

The following examples are presented to further illustrate the present invention and should not be construed as limiting the invention. Unless otherwise specified, the technical means used in the examples are conventional means well known to those skilled in the art. Reagents, methods and apparatus used in the present invention are conventional in the art unless otherwise indicated.

Example 1

1. Preparation:

(1) CdS solid powder 0.15g (99.999%, Alfaaesar) and SnO₂0.01g of powder (99.5%, AlfaAesar) was ground in an agate mortar and mixed uniformly to obtain a precursor mixed powder;

(2) ultrasonically cleaning a mica substrate with acetone, ethanol and deionized water for 15min respectively; and then, drying the mica sheet by using a nitrogen gun to obtain the pretreated mica sheet substrate.

(3) Pouring the mixed powder obtained in the step 1 into a porcelain boat, placing the porcelain boat at the central temperature area of a tube furnace, placing the pretreated mica sheet substrate on the porcelain boat at a low-temperature area at the downstream of a central heating area by 11cm, placing the porcelain boats in a quartz tube, and before the growth process, using high-purity mixed gas of 10% hydrogen and 90% argon at 40sccm (cm) of the high-purity mixed gas³And/min) exhausting air for 1-2 h through the quartz tube, and exhausting air in the quartz tube.

(4) After the exhaust, the mixture was heated to 1050 ℃ at a rate of about 100 ℃/min for about 1 hour, and the gas flow rate was maintained at 20sccm during the heating. And after the reaction is finished, naturally cooling to room temperature to obtain a yellow Sn doped CdS sample on the inner wall of the quartz tube and the mica substrate.

2. And (3) performance testing: and transferring the Sn doped CdS sample to a cleaned silicon wafer or glass wafer by using a clean forceps, and further characterizing the appearance and the photoelectric property. FIG. 2 is an SEM photograph of a branched structure and a comb-like structure of the Sn-doped CdS array prepared in example 1; wherein, (a) the Sn doped CdS array branch structure; (b) sn doped CdS comb structures. As can be seen from FIG. 2, in the growth process, the Sn nanowire is used as a template to assist the synthesis of the CdS branch structure, and the surface of the prepared branch structure is smooth and clean, thereby facilitating the further research on the photoelectric properties. Fig. 3 is a luminescence fluorescence diagram of the Sn-doped CdS array branch structure prepared in example 1, wherein the inset is a corresponding microscope image. As can be seen from FIG. 3, the defect level luminescence peak in the wavelength range of 550-800nm is obtained due to Sn doping, while the band edge luminescence peak of CdS around 500nm is split into two peaks, and the peak position and the distance between the two peaks are changed along with the reduction of temperature. In addition, a new light-emitting peak appears at a position of about 530nm at low temperature (<220K), the peak position is 532nm, and a new way is provided for a light-emitting mechanism of a doped heterostructure. FIG. 4 is a temperature dependent fluorescence spectrum of the Sn doped CdS comb-like structure prepared in example 1. It can be known from fig. 4 that at low temperature (<220K), due to the influence of the morphology of the Sn-doped CdS branch structure and Sn-doping and other factors, an obvious peak separation and a new light emission peak (524.9nm) appear in the fluorescence spectrum, which indicates that the Sn-doped CdS branch structure effectively regulates and controls the optical property of CdS. This is useful for further study of the light-emitting mechanism and physical mechanism description of the branched structure.

Example 2

The difference from example 1 is that: by adjusting the growth parameters: the growth temperature is 850-1150 ℃, the reaction time is 20-120 min, and the temperature rise rate is 40-100 ℃/min, so that the morphology of the branch structure can be adjusted. FIG. 5 is an SEM photograph of a Sn doped CdS leaf-like branched structure prepared in example 2. Wherein, (a) and (b) partial photographs of the Sn doped CdS leaf-like branch structure. As can be seen from FIG. 5, when the growth temperature is high (1150 ℃), the CdS branch structure has a large size (300-1500 μm long), and a sheet-like branch structure with a large thickness (1-5 μm) is easily formed. Illustrating the branched structure of Sn doped CdS leaf-like that is easily obtained by adjusting the growth temperature to further increase (1150 ℃).

Example 3

The difference from example 1 is that: the gas flow speed in the growth process is adjusted to be fast (40sccm), only the gas flow speed is changed, and other conditions are not changed, so that the branched structure of the nano-cone is obtained. Fig. 6 is an SEM image of the branched structure of the Sn-doped CdS cone trunk prepared in example 3, in which (a) and (b) partial photographs of the branched structure of the Sn-doped CdS cone trunk. As can be seen from FIG. 6, the gas flow rate during the growth process affects the morphology of the synthesized sample to some extent, and a tapered trunk and branches with smaller diameters (<200nm) are easily formed at a faster gas flow (40 sccm).

Example 4

The difference from example 1 is that:adjusting SnO in precursor powder₂Increased content (CdS solid powder and SnO₂The mass ratio of the powders is 10:1), a structure comprising Sn metal particles in segments in a branched structure is formed. Fig. 7 is a microscope image of Sn metal balls existing in the branches during the formation of the branched structure of Sn-doped CdS prepared in example 4. Wherein (a) is an image of an optical microscope at a magnification of × 20 and (b) is a magnification of × 50. As can be seen from FIG. 7, the Sn content in the precursor powder is high (CdS solid powder and SnO)₂The mass ratio of the powder is 10:1), a separated Sn metal ball exists in the branch shape of the sample, Sn can be separated out in the growth process because the Sn nanowire is used as a catalyst and a template, and an ion doping form exists at the CdS part after the Sn is separated out, so that a branch structure of Sn doped CdS is formed.

Example 5

The difference from example 1 is that: the growth temperature is adjusted to 1150 ℃, and the reaction gas is 12 percent of H in the growth process₂88% Ar, forming a parallel comb structure as shown in FIG. 8. Fig. 8 is a microscope photograph of an optical waveguide of the Sn-doped CdS parallel comb structure prepared in example 5, with corresponding optical microscope images being shown in the inset. As can be seen from FIG. 8, in the Sn-doped CdS parallel nano-comb structure, light can propagate for a distance of 300-800 μm, and has a good optical waveguide performance.

According to the method, the morphology of the branch structure is effectively and controllably adjusted through growth parameters, and in the synthesis process, Sn metal is used not only as a catalyst, but also as a template, and the Sn-doped CdS branch structure is obtained through growth. Different from the traditional growth method, the method does not need auxiliary conditions, can obtain the high-quality CdS branch structure by one-step growth through adjusting synthesis parameters, greatly saves the synthesis cost and time, and has innovation in the field of low-dimensional semiconductor synthesis.

The above embodiments are preferred embodiments of the present invention, but the present invention is not limited to the above embodiments, and any other changes, modifications, substitutions, combinations and simplifications which do not depart from the spirit and principle of the present invention should be construed as equivalents thereof, and all such changes, modifications, substitutions, combinations and simplifications are intended to be included in the scope of the present invention.