CN104831253B - Single granule layer nanometer diamond film with strong Si-V luminescence, and production method thereof - Google Patents

Abstract

The invention provides a single-particle-layer nano-diamond film with strong Si-V luminescence and a preparation method: a single-particle-layer nano-diamond film with a thickness of 500-700nm is prepared on a single crystal silicon substrate by using a hot wire chemical vapor deposition method thin film; and then keep the thin film in air at a temperature of 600° C. for 10 to 50 minutes to obtain the single particle layer nano-diamond thin film with strong Si-V luminescence. The nano-diamond film prepared by the present invention has the characteristics of a single particle layer, the thickness is 500-700nm, the Si-V luminous peak shape of the film is sharp, and the Si-V luminous intensity is greatly improved. , optoelectronic devices, biomarkers, semiconductor devices and field emission displays have very important scientific significance and engineering value.

Description

A single particle layer nano-diamond film with strong Si-V luminescence and its preparation method

(1) Technical field

The invention relates to a single particle layer nano-diamond film with strong Si-V luminescence (the luminescence peak in the photoluminescence spectrum is at 738nm) and a preparation method thereof.

(2) Background technology

The silicon-vacancy (Si-V) center in diamond has a luminescence peak at 738nm in the photoluminescence spectrum (PL spectrum), a narrow line width (~5nm), and a short luminescence lifetime (1.2ns), making Si- The V luminescent center has become a very potential single photon source, and has broad application prospects in the fields of quantum information processing, optoelectronic devices, biomarkers, semiconductor devices, and field emission displays.

Constructing optically active defects in nanodiamond grains can obtain a single optically active film with stronger and narrower luminescence, laying the foundation for the realization of micronano and miniaturization of optoelectronic devices. In the nano-diamond film prepared by chemical vapor deposition (CVD), the Si-V luminescent center is usually formed by the silicon in the substrate or quartz tube entering the film in the form of non-intentional doping during the film growth process; this The uncontrollable non-intentional doping method makes some films have Si-V luminescence, while some films do not have Si-V luminescence properties, that is, the Si-V luminescence properties of films are difficult to control. In the previous study, the prepared nano-diamond film without Si-V luminescence was oxidized at a certain temperature to obtain Si-V luminescence; the research results also showed that the surface termination state of the film is more important to its Si-V luminescence. The effect; that is, the hydrogen termination on the surface of the film has an inhibitory effect on the Si-V luminescence, while the oxygen termination is beneficial to the Si-V luminescence. In the previous research, the nano-diamond film with a thickness of 3-10 μm was oxidized; these films are thicker, with more complex microstructure and composition, and the Si-V luminous intensity of the oxidized film is not high enough to meet the requirements of optoelectronic applications. Demand, it is necessary to further increase the intensity of Si-V luminescence in thin films. Therefore, the present invention intends to reduce the thickness of the film, and control the surface termination state during the film growth process, and explore the preparation method of nano-diamond film with strong Si-V luminescence performance, which is useful for realizing the nano-diamond film in single photon source, quantum information Applications in fields such as processing, optoelectronic devices and field emission displays are of great scientific significance and engineering value.

In the applicant's authorized patent "an n-type nano-diamond film and its preparation method" (ZL200910155306.3), it is proposed to implant donor impurity ions into the nano-diamond film, and vacuum anneal the film (with a thickness of 4-10 μm) , obtained n-type nano-diamond films with lower resistivity and higher mobility. The patent involves vacuum annealing and the electrical properties of the thin film, but does not involve the Si-V luminescent properties of the thin film. The application adopts the hot wire chemical vapor deposition method to prepare a film with a particle layer thickness (thickness is 500-700nm), that is, a single particle layer nano-diamond film; and the film is oxidized in the air, which effectively improves the thickness of the film. Si-V luminescence properties. The current literature does not involve the preparation of single particle layer nano-diamond films.

(3) Contents of the invention

The object of the present invention is to provide a kind of strong Si-V luminescence (Si-V luminescence refers to that characteristic peak is positioned at 738nm place in photoluminescence spectrum (PL spectrum), and line width is narrower (～5nm), and luminous lifetime is very short (1.2ns), making Si-V a very potential single photon source) single particle layer nano-diamond film and its preparation method.

The technical scheme adopted in the present invention is:

A method for preparing a single particle layer nano-diamond film with strong Si-V luminescence, the method comprising the following steps: (1) using a hot wire chemical vapor deposition method to prepare a 500-700nm thick film on a single crystal silicon substrate (2) keeping the single particle layer nanodiamond film obtained in step (1) in the air at a temperature of 600° C. for 10 to 50 minutes to obtain the strong Si-V luminescence Single particle layer nanodiamond film.

The invention adopts the hot wire chemical vapor deposition method to prepare a single-particle layer nano-diamond film with a thickness of 500-700nm, and performs thermal oxidation treatment on the film in air, and the Si-V luminous intensity of the prepared film is micron-level compared with the thickness The Si-V luminescence intensity of the nanodiamond film is greatly enhanced. This scheme effectively improves the Si-V luminescence intensity of the nanodiamond film.

The present invention also provides a kind of single particle layer nano-diamond film with strong Si-V luminescence, and described film is made by following method: (1) adopt hot wire chemical vapor deposition method, prepare thickness on single crystal silicon substrate 500-700nm single-particle layer nano-diamond film; (2) the single-particle layer nano-diamond film obtained in step (1) was incubated in the air at a temperature of 600° C. for 10 to 50 minutes to obtain the strong Si- V Luminescent single particle layer nanodiamond film.

In the step (1), the single-particle layer nano-diamond film is prepared on a single-crystal silicon substrate by hot-filament chemical vapor deposition (HFCVD), which can be carried out by conventional chemical vapor deposition equipment. The thickness of the diamond film is 500-700nm.

The specific method adopted in the general procedure (1) is as follows: the monocrystalline silicon wafer is polished with diamond abrasive paste for half an hour, and the polished single crystal silicon wafer is sequentially cleaned with deionized water and acetone ultrasonically, dried and used as a lining for the growth of nano-diamond film. At the bottom, put the monocrystalline silicon substrate into the hot wire chemical vapor deposition equipment, use acetone as the carbon source, and use hydrogen bubbling to bring the acetone into the reaction chamber, wherein the flow ratio of hydrogen and acetone is 200:90, heat The distance between the wire and the monocrystalline silicon substrate is 7mm, the reaction power is 2200W, and the working pressure is 1.63Kpa; the film growth time is 15-20 minutes; no bias voltage is applied during the reaction process; The temperature is lowered and cooled to prepare a single particle layer nano-diamond film with a thickness of 500-700nm.

The hot wire chemical vapor deposition equipment was purchased from Shanghai Jiaoyou Diamond Coating Co., Ltd., model JUHF CVD001.

The step (2) is preferably one of the following operating methods:

(i) keeping the single particle layer nano-diamond film obtained in step (1) in the air at a temperature of 600°C for 20 minutes to obtain the single particle layer nano-diamond film with strong Si-V luminescence;

(ii) the single-particle-layer nano-diamond film obtained in step (1) was incubated in the air at a temperature of 600°C for 30 minutes to obtain the single-particle-layer nano-diamond film with strong Si-V luminescence;

(iii) keeping the single-particle-layer nano-diamond film obtained in step (1) in air at a temperature of 600° C. for 50 minutes to prepare the single-particle-layer nano-diamond film with strong Si-V luminescence.

The beneficial effects of the present invention are mainly reflected in: (1) adopting the hot wire chemical vapor deposition method to prepare a single particle layer nano-diamond film with a thickness of 500-700nm; Substantial progress has been made in nano-diamond films of 3-10 μm. (2) Keeping the nano-diamond film of a single particle layer in the air at a certain temperature for a certain period of time, so that the nano-diamond film has a strong Si-V luminescence, which is 10-20 times higher than the Si-V luminescence intensity of the unoxidized film; Its Si-V luminous intensity is about 20 times higher than that of the oxidized nano-diamond film with micron-scale thickness. (3) The single particle layer nano-diamond film with strong Si-V luminescence prepared by the present invention obtains a new type of film, which provides a new idea for the application of nano-diamond film in optoelectronics and other fields.

The invention has a simple solution and is easy to operate, solves the problems of unstable luminous performance and low luminous intensity of Si-V thin films prepared by chemical vapor deposition, and lays a foundation for preparing nano-diamond optoelectronic devices. The Si-V luminous intensity of the prepared single particle layer nano-diamond film is very strong, which is very important for realizing its application in the fields of single photon source, quantum information processing, optoelectronic device, biomarker, semiconductor device and field emission display. scientific significance and engineering value.

(4) Description of drawings

Fig. 1 is the field emission scanning electron microscope (FESEM) photo of the single particle layer nano-diamond thin film of embodiment 1.

2 is a cross-sectional SEM image of the single particle layer nano-diamond film of Example 1.

Fig. 3 is the photoluminescence spectrum of the single particle layer nano-diamond thin film of embodiment 1, and its lower left small figure is the Raman spectrogram of thin film.

Fig. 4 is a photoluminescence spectrum diagram of a single particle layer nano-diamond film incubated in air at 600°C for 20 minutes.

Fig. 5 is a cross-sectional SEM image of a single particle layer nano-diamond film kept at 600°C for 20 minutes in air.

Fig. 6 is a photoluminescence spectrum diagram of a single particle layer nano-diamond film incubated in air at 600°C for 30 minutes.

Fig. 7 is a cross-sectional SEM image of a single particle layer nano-diamond film kept at 600°C for 30 minutes in air.

Fig. 8 is a photoluminescence spectrum diagram of a single particle layer nano-diamond film incubated in air at 600°C for 50 minutes.

Fig. 9 is a cross-sectional SEM image of a single particle layer nano-diamond film kept at 600°C in air for 50 minutes.

(5) Specific implementation methods

The present invention is further described below in conjunction with specific embodiment, but protection scope of the present invention is not limited thereto:

Example 1:

Polish the monocrystalline silicon wafer with nano-scale diamond powder, and the grinding time is about half an hour. Polished silicon wafers were ultrasonically cleaned with deionized water and acetone in turn, dried, and used as substrates for the growth of nano-diamond films. The hot wire chemical vapor deposition method (chemical vapor deposition equipment was purchased from Shanghai Jiaoyou Diamond Coating Co., Ltd., model JUHF CVD 001) was used, acetone was used as the carbon source, and acetone was brought into the reaction chamber by hydrogen bubbling. The flow ratio to acetone is 200:90, the reaction power is 2200W, the distance between the hot wire and the substrate silicon wafer is 7mm, and the working pressure is 1.63Kpa; no bias is applied during the reaction, and the preparation time is 15 minutes; after the growth , the temperature of the sample is cooled under the condition of no hydrogen, and a single particle layer nano-diamond film with a thickness of 500-700nm is prepared. The surface morphology and cross-section of the film were observed by field emission scanning electron microscopy, and the luminescent properties of the film were tested by photoluminescence spectroscopy.

In addition, as a comparison, a nano-diamond film with a thickness of micron level was prepared, and the method was as follows: a single-crystal silicon wafer was polished with nano-scale diamond powder, and the polishing time was about half an hour. Polished silicon wafers are used as substrates for the growth of nano-diamond films after ultrasonic cleaning. The hot wire chemical vapor deposition method (chemical vapor deposition equipment was purchased from Shanghai Jiaoyou Diamond Coating Co., Ltd.) was used, acetone was used as the carbon source, and acetone was brought into the reaction chamber by hydrogen bubbling. The temperature of the reaction chamber was controlled at 600~ 700° C., the preparation time is 5 hours, and a nano-diamond film with a thickness of 3 μm is prepared. The nanodiamond film with a thickness of 3 μm has no Si-V luminescence peak at 738nm.

Figure 1 is a field emission scanning electron microscope (FESEM) photo of a single particle layer nano-diamond film. It can be seen that the film is composed of nanoscale diamond grains; Figure 2 is a cross-sectional SEM image of the film. It is a single particle layer nano-diamond film. The thickness of the film can also be measured from Figure 2, which is about 540nm; Figure 3 is the photoluminescence spectrum of the film, which is tested by the light emission mode of a Raman spectrometer with a wavelength of 514nm. It can be seen that the film has a Si-V luminescence peak at 738nm, that is, the single particle layer nano-diamond film prepared by this scheme has Si-V luminescence, while the nano-diamond film with a thickness of 3 μm does not have Si-V luminescence. It can be seen that this scheme The prepared single-particle layer nano-diamond film has substantial progress; but its luminescence peak is low, and the normalized intensity of the Si-V luminescence peak (ratio of the intensity of the luminescence peak at 738nm to the intensity of the peak at 540nm) is 1.6; It shows that the single particle layer nano-diamond film prepared by hot filament chemical vapor deposition has weak Si-V luminescence properties. The lower left panel in Fig. 3 is the Raman spectrum of the single particle layer nano-diamond film. The spectrum shows that a diamond characteristic peak appears at 1332cm- ¹ , and a graphite peak of disordered sp ² bonds can also be observed at 1560cm ^-1 , indicating that the film is mainly Composed of diamond phase and disordered graphite phase, it is a typical nano-diamond film.

The above-mentioned single-particle-layer nano-diamond film was kept warm in the air at 600°C for 20 minutes, and the luminescence peak of the film was tested by Raman spectrum with a wavelength of 514nm, as shown in FIG. 4 . It can be seen that a strong luminescence peak appears at around 738nm in the spectrum, and the normalized intensity of the Si-V luminescence peak is 8, which is much higher than that of the unoxidized single particle layer film.

The nano-diamond film with a thickness of 3 μm was oxidized under the same conditions, kept in air at 600°C for 20 minutes, and the luminescence peak of the film was tested by Raman spectrum with a wavelength of 514nm. The results showed that the Si-V normalized luminescence intensity was only 0.28, indicating that the single particle layer film oxidized for 20 minutes had strong Si-V luminescence properties, and the Si-V luminescence peak intensity was much higher than that of the oxidized micron-scale film. .

Figure 5 is a cross-sectional SEM image of a single particle layer nano-diamond film at 600°C for 20 minutes in air. It can be seen that the thickness of the film is 350nm, that is, the thickness of the film is reduced by oxidation; the film is still composed of a layer of particles, which is a single particle layer nanodiamond films.

Example 2:

The monocrystalline silicon wafer is polished with nanometer diamond powder, and the polishing time is about half an hour. The polished silicon wafers were washed with deionized water and acetone in an ultrasonic machine, dried, and used as substrates for the growth of nano-diamond films. The hot wire chemical vapor deposition method (chemical vapor deposition equipment was purchased from Shanghai Jiaoyou Diamond Coating Co., Ltd., model JUHF CVD 001) was used, acetone was used as the carbon source, and acetone was brought into the reaction chamber by hydrogen bubbling. The flow ratio with acetone is 200:90, the reaction power is 2200W, the distance between the hot wire and the substrate silicon wafer is 7mm, the working pressure is 1.63Kpa; no bias is applied during the reaction, and the film preparation time is 15 minutes. After the growth is finished, the temperature of the sample is cooled under the condition of not flowing hydrogen, and a single particle layer nano-diamond film with a thickness of 500-600 nm is prepared.

The above-mentioned single particle layer nano-diamond film was kept warm in the air at 600° C. for 30 minutes, and the luminescence peak of the film was tested by Raman spectrum with a wavelength of 514 nm, as shown in FIG. 6 . It can be seen that there is a strong luminescence peak around 738nm in the spectrogram, and the normalized intensity of the Si-V luminescence peak is 12, which is greatly improved compared with the unoxidized film; it shows that the film oxidized for 30 minutes has a strong Si-V luminescence properties.

Figure 7 is a cross-sectional SEM image of a single particle layer nano-diamond film at 600°C for 30 minutes in air. It can be seen that the thickness of the film is 300nm, that is, the thickness of the film is reduced by oxidation; the film is still composed of a layer of particles, which is a single particle layer nanodiamond films.

Example 3:

The monocrystalline silicon wafer is polished with nanometer diamond powder, and the polishing time is about half an hour. The polished silicon wafers were washed with deionized water and acetone in an ultrasonic machine, dried, and used as substrates for the growth of nano-diamond films. The hot wire chemical vapor deposition method (chemical vapor deposition equipment purchased from Shanghai Jiaoyou Diamond Coating Co., Ltd., model JUHF CVD 001) was used, with acetone as the carbon source, and acetone was brought into the reaction chamber by hydrogen bubbling. , The flow ratio of hydrogen gas is 200:90, the power is 2200W, the distance between the hot wire and the substrate silicon wafer is 7mm, and the working pressure is 1.63Kpa; no bias is applied during the reaction process, and the preparation time is 15 minutes; after the growth is over, The temperature of the sample is lowered and cooled under the condition of not flowing hydrogen, and a single particle layer nano-diamond film with a thickness of 500-600nm is prepared.

The above-mentioned single-particle-layer nano-diamond film was incubated in air at 600° C. for 50 minutes, and the luminescence peak of the film was tested by Raman spectrum with a wavelength of 514 nm, as shown in FIG. 8 . It can be seen that a strong luminescence peak appears at around 738nm in the spectrogram, and the normalized intensity of the Si-V luminescence peak increases to 28, which is much higher than that of the unoxidized film; it shows that the film oxidized for 50 minutes has a strong Strong Si-V luminescence properties.

Figure 9 is a cross-sectional SEM image of a single particle layer nano-diamond film kept at 600°C for 50 minutes in air. It can be seen that the thickness of the film is 280nm, that is, oxidation reduces the thickness of the film; the film is still composed of a layer of particles, which is a single particle layer nanodiamond films.

Claims (4)

1. A preparation method of a single-particle layer nano-diamond film with strong Si-V luminescence, characterized in that the method comprises the following steps: (1) adopting the hot wire chemical vapor deposition method, placing the single-crystal silicon substrate into Hot wire chemical vapor deposition equipment uses acetone as the carbon source, and uses hydrogen bubbling to bring acetone into the reaction chamber. The flow ratio of hydrogen and acetone is 200:90, and the distance between the hot wire and the single crystal silicon substrate is 7mm, the reaction power is 2200W, the working pressure is 1.63Kpa; the film growth time is 15-20 minutes; no bias voltage is applied during the reaction process, and after the growth is completed, the temperature is lowered and cooled under the condition of no hydrogen, and the thickness is 500- 700nm single particle layer nano-diamond film; (2) the single particle layer nano-diamond film obtained in step (1) is incubated in the air at a temperature of 600° C. for 10 to 50 minutes to obtain the strong Si-V luminescence single particle layer nanodiamond film. 2. method as claimed in claim 1, it is characterized in that described step (1) first adopts diamond grinding paste to polish half an hour to monocrystalline silicon chip, and the monocrystalline silicon chip after polishing is cleaned with deionized water and acetone ultrasonic wave successively , A single crystal silicon substrate grown as a nano-diamond film after drying. 3. the single particle layer nano-diamond film that the method as claimed in claim 1 or 2 makes. 4. The nano-diamond film of single particle layer as claimed in claim 3, characterized in that said film has very strong Si-V luminescent properties at 738nm of photoluminescence spectrum.