CN117434303A - Super-resolution Raman/fluorescence/photocurrent two-dimensional scanning imaging combined characterization system based on micro-cantilever-microsphere probe - Google Patents
Super-resolution Raman/fluorescence/photocurrent two-dimensional scanning imaging combined characterization system based on micro-cantilever-microsphere probe Download PDFInfo
- Publication number
- CN117434303A CN117434303A CN202311312671.7A CN202311312671A CN117434303A CN 117434303 A CN117434303 A CN 117434303A CN 202311312671 A CN202311312671 A CN 202311312671A CN 117434303 A CN117434303 A CN 117434303A
- Authority
- CN
- China
- Prior art keywords
- microsphere
- cantilever
- micro
- photocurrent
- resolution
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Pending
Links
- 239000004005 microsphere Substances 0.000 title claims abstract description 131
- 239000000523 sample Substances 0.000 title claims abstract description 66
- 238000003384 imaging method Methods 0.000 title claims abstract description 52
- 238000001069 Raman spectroscopy Methods 0.000 title claims abstract description 36
- 238000012512 characterization method Methods 0.000 title claims abstract description 23
- 238000000034 method Methods 0.000 claims abstract description 15
- 238000012360 testing method Methods 0.000 claims description 18
- VYPSYNLAJGMNEJ-UHFFFAOYSA-N Silicium dioxide Chemical compound O=[Si]=O VYPSYNLAJGMNEJ-UHFFFAOYSA-N 0.000 claims description 16
- 239000000853 adhesive Substances 0.000 claims description 13
- 230000001070 adhesive effect Effects 0.000 claims description 13
- 238000006073 displacement reaction Methods 0.000 claims description 8
- 239000000377 silicon dioxide Substances 0.000 claims description 8
- 239000003292 glue Substances 0.000 claims description 6
- 239000000758 substrate Substances 0.000 claims description 5
- 238000004458 analytical method Methods 0.000 claims description 4
- 239000004205 dimethyl polysiloxane Substances 0.000 claims description 4
- 229920000435 poly(dimethylsiloxane) Polymers 0.000 claims description 4
- 239000002245 particle Substances 0.000 claims description 3
- 239000007787 solid Substances 0.000 claims description 3
- -1 polydimethylsiloxane Polymers 0.000 claims description 2
- 238000001179 sorption measurement Methods 0.000 claims 1
- 238000002189 fluorescence spectrum Methods 0.000 abstract description 6
- 238000001228 spectrum Methods 0.000 abstract description 6
- 239000000463 material Substances 0.000 abstract description 3
- 230000008569 process Effects 0.000 abstract description 3
- 230000003287 optical effect Effects 0.000 description 26
- 238000005516 engineering process Methods 0.000 description 11
- 239000011521 glass Substances 0.000 description 7
- 238000001237 Raman spectrum Methods 0.000 description 5
- 239000000919 ceramic Substances 0.000 description 5
- 238000009826 distribution Methods 0.000 description 5
- 230000006870 function Effects 0.000 description 5
- 230000000694 effects Effects 0.000 description 4
- 230000005284 excitation Effects 0.000 description 4
- CWQXQMHSOZUFJS-UHFFFAOYSA-N molybdenum disulfide Chemical compound S=[Mo]=S CWQXQMHSOZUFJS-UHFFFAOYSA-N 0.000 description 4
- 229910052982 molybdenum disulfide Inorganic materials 0.000 description 4
- 238000004630 atomic force microscopy Methods 0.000 description 3
- 230000005693 optoelectronics Effects 0.000 description 3
- 238000002360 preparation method Methods 0.000 description 3
- 238000012546 transfer Methods 0.000 description 3
- 229910008760 WITec Inorganic materials 0.000 description 2
- 239000002390 adhesive tape Substances 0.000 description 2
- 230000003321 amplification Effects 0.000 description 2
- ROUIDRHELGULJS-UHFFFAOYSA-N bis(selanylidene)tungsten Chemical compound [Se]=[W]=[Se] ROUIDRHELGULJS-UHFFFAOYSA-N 0.000 description 2
- 238000004364 calculation method Methods 0.000 description 2
- 230000008859 change Effects 0.000 description 2
- 238000010586 diagram Methods 0.000 description 2
- 238000009792 diffusion process Methods 0.000 description 2
- 238000001506 fluorescence spectroscopy Methods 0.000 description 2
- 238000005286 illumination Methods 0.000 description 2
- 230000010354 integration Effects 0.000 description 2
- 230000033001 locomotion Effects 0.000 description 2
- 238000005259 measurement Methods 0.000 description 2
- 229910052751 metal Inorganic materials 0.000 description 2
- 239000002184 metal Substances 0.000 description 2
- 238000003199 nucleic acid amplification method Methods 0.000 description 2
- 238000005424 photoluminescence Methods 0.000 description 2
- 238000012545 processing Methods 0.000 description 2
- 238000011160 research Methods 0.000 description 2
- 230000004044 response Effects 0.000 description 2
- 235000012239 silicon dioxide Nutrition 0.000 description 2
- 230000003595 spectral effect Effects 0.000 description 2
- 238000004611 spectroscopical analysis Methods 0.000 description 2
- 238000010998 test method Methods 0.000 description 2
- CXOFVDLJLONNDW-UHFFFAOYSA-N Phenytoin Chemical compound N1C(=O)NC(=O)C1(C=1C=CC=CC=1)C1=CC=CC=C1 CXOFVDLJLONNDW-UHFFFAOYSA-N 0.000 description 1
- XUIMIQQOPSSXEZ-UHFFFAOYSA-N Silicon Chemical compound [Si] XUIMIQQOPSSXEZ-UHFFFAOYSA-N 0.000 description 1
- 230000009471 action Effects 0.000 description 1
- 238000013459 approach Methods 0.000 description 1
- 230000008901 benefit Effects 0.000 description 1
- 238000004891 communication Methods 0.000 description 1
- 238000010276 construction Methods 0.000 description 1
- 230000001276 controlling effect Effects 0.000 description 1
- 230000008021 deposition Effects 0.000 description 1
- 239000003814 drug Substances 0.000 description 1
- 238000013401 experimental design Methods 0.000 description 1
- 238000002474 experimental method Methods 0.000 description 1
- 230000008713 feedback mechanism Effects 0.000 description 1
- 239000000835 fiber Substances 0.000 description 1
- 239000012634 fragment Substances 0.000 description 1
- 210000004209 hair Anatomy 0.000 description 1
- 230000006872 improvement Effects 0.000 description 1
- 230000003993 interaction Effects 0.000 description 1
- 238000004519 manufacturing process Methods 0.000 description 1
- 230000007246 mechanism Effects 0.000 description 1
- 238000000386 microscopy Methods 0.000 description 1
- 239000013307 optical fiber Substances 0.000 description 1
- 238000005457 optimization Methods 0.000 description 1
- 230000000737 periodic effect Effects 0.000 description 1
- 238000000103 photoluminescence spectrum Methods 0.000 description 1
- 239000000843 powder Substances 0.000 description 1
- 230000009467 reduction Effects 0.000 description 1
- 230000001105 regulatory effect Effects 0.000 description 1
- 238000012216 screening Methods 0.000 description 1
- 230000008054 signal transmission Effects 0.000 description 1
- 229910052710 silicon Inorganic materials 0.000 description 1
- 239000010703 silicon Substances 0.000 description 1
- 238000006467 substitution reaction Methods 0.000 description 1
- 238000001429 visible spectrum Methods 0.000 description 1
- 210000002268 wool Anatomy 0.000 description 1
Classifications
-
- G—PHYSICS
- G01—MEASURING; TESTING
- G01Q—SCANNING-PROBE TECHNIQUES OR APPARATUS; APPLICATIONS OF SCANNING-PROBE TECHNIQUES, e.g. SCANNING PROBE MICROSCOPY [SPM]
- G01Q60/00—Particular types of SPM [Scanning Probe Microscopy] or microscopes; Essential components thereof
- G01Q60/24—AFM [Atomic Force Microscopy] or apparatus therefor, e.g. AFM probes
- G01Q60/38—Probes, their manufacture, or their related instrumentation, e.g. holders
-
- G—PHYSICS
- G01—MEASURING; TESTING
- G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
- G01N21/00—Investigating or analysing materials by the use of optical means, i.e. using sub-millimetre waves, infrared, visible or ultraviolet light
- G01N21/62—Systems in which the material investigated is excited whereby it emits light or causes a change in wavelength of the incident light
- G01N21/63—Systems in which the material investigated is excited whereby it emits light or causes a change in wavelength of the incident light optically excited
- G01N21/64—Fluorescence; Phosphorescence
- G01N21/645—Specially adapted constructive features of fluorimeters
- G01N21/6456—Spatial resolved fluorescence measurements; Imaging
- G01N21/6458—Fluorescence microscopy
-
- G—PHYSICS
- G01—MEASURING; TESTING
- G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
- G01N21/00—Investigating or analysing materials by the use of optical means, i.e. using sub-millimetre waves, infrared, visible or ultraviolet light
- G01N21/62—Systems in which the material investigated is excited whereby it emits light or causes a change in wavelength of the incident light
- G01N21/63—Systems in which the material investigated is excited whereby it emits light or causes a change in wavelength of the incident light optically excited
- G01N21/65—Raman scattering
-
- G—PHYSICS
- G01—MEASURING; TESTING
- G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
- G01N21/00—Investigating or analysing materials by the use of optical means, i.e. using sub-millimetre waves, infrared, visible or ultraviolet light
- G01N21/84—Systems specially adapted for particular applications
-
- G—PHYSICS
- G01—MEASURING; TESTING
- G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
- G01N23/00—Investigating or analysing materials by the use of wave or particle radiation, e.g. X-rays or neutrons, not covered by groups G01N3/00 – G01N17/00, G01N21/00 or G01N22/00
- G01N23/22—Investigating or analysing materials by the use of wave or particle radiation, e.g. X-rays or neutrons, not covered by groups G01N3/00 – G01N17/00, G01N21/00 or G01N22/00 by measuring secondary emission from the material
- G01N23/227—Measuring photoelectric effect, e.g. photoelectron emission microscopy [PEEM]
-
- G—PHYSICS
- G01—MEASURING; TESTING
- G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
- G01N21/00—Investigating or analysing materials by the use of optical means, i.e. using sub-millimetre waves, infrared, visible or ultraviolet light
- G01N21/62—Systems in which the material investigated is excited whereby it emits light or causes a change in wavelength of the incident light
- G01N21/63—Systems in which the material investigated is excited whereby it emits light or causes a change in wavelength of the incident light optically excited
- G01N21/65—Raman scattering
- G01N2021/653—Coherent methods [CARS]
- G01N2021/656—Raman microprobe
Abstract
The invention discloses a super-resolution Raman/fluorescence/photocurrent two-dimensional scanning imaging combined characterization system based on a micro-cantilever-microsphere probe. The microsphere is fixed on an atomic force needle point by utilizing a self-designed micromanipulation process to obtain the micro-cantilever-microsphere probe, the microsphere is supported by an atomic force micro-cantilever bracket, a microsphere lens is added in a system light path, super-resolution focusing light spots are generated after passing through transparent medium microspheres, and the precise control of the microsphere lens is realized by an atomic force microscope signal feedback and control system, so that diffraction limit resolution exceeding that of an original system, namely super-resolution Raman/fluorescence/photocurrent imaging, is finally realized on Raman, fluorescence spectrum and photocurrent scanning imaging. The super-resolution spectrum and photocurrent imaging method provided by the invention is economical and efficient, and provides a reliable tool for comprehensively understanding and revealing the photoelectric characteristics of materials.
Description
Technical Field
The invention belongs to the technical field of super-resolution optics, and particularly relates to a manufacturing method of a transparent medium microsphere probe and super-resolution Raman/fluorescence/photocurrent two-dimensional scanning imaging combined characterization based on the probe.
Background
The traditional optical microscope imaging system is simple, does not need complex sample preparation, is easy to integrate with fluorescence (photoluminescence), raman spectrum and other technologies, is a convenient, quick, economical and efficient optical measurement technology, and is widely applied to various subjects as the most basic characterization means. However, the resolution of the conventional optical microscope is generally not more than half of the wavelength according to the rayleigh criterion, because the conventional optical microscope is affected by the far-field diffraction limit, that is, the transverse resolution limit is about 200nm under visible spectrum imaging. The research of the method for improving the resolution thereof pursues super-resolution optical characterization exceeding the diffraction limit, and has great significance for the progress of medicine and biotechnology, nanotechnology, information technology and the like. Therefore, it has been one of the important subjects of research in the scientific community.
In 2011 Wang et al reported the first super-resolution imaging technique based on silica microsphere lenses, obtaining a resolution of 50nm under white light (Nature Communication, DOI: 10.1038/ncoms 1211). This simple and effective technique provides a new possibility for real-time super-resolution imaging. The super-resolution imaging technology realized by using the medium microspheres is called as a microsphere-assisted super-resolution optical technology, and is a powerful means of super-resolution imaging because of the simple, economical and efficient characteristics of real-time observation and no pollution to target samples. The dielectric microsphere has an optical nanojet effect, and when excited and illuminated by light waves, an elongated and narrow jet-like light beam is generated near the back light surface of the microsphere and at several times the wavelength, thereby obtaining a focused light spot smaller than the diffraction limit. In addition, the dielectric microsphere also has unique optical characteristics such as whisper gallery mode, unidirectional antenna and the like, so that the focusing, the limiting and the scattering of light can be controlled on a microscale, and the signal resolution and the signal intensity are further improved. The microsphere lens is combined with a common optical microscope, so that the transverse spatial resolution and the axial focal depth of field of the microscope can be improved, super-resolution imaging breaking through diffraction limit is realized, and a lot of microscopic information under the resolution of tens of nanometers is obtained.
Early microsphere-based super-resolution imaging systems mostly used stationary dielectric microspheres in direct contact with the sample to enhance the resolution or optical signal of the local sample area beneath it. This approach is limited in many ways: first, the deposited microspheres provide only a very limited field of view; secondly, the falling position of each microsphere cannot be controlled, so that the observation position is random; finally, microsphere solution deposition inevitably contaminates the substrate and sample with thousands of microspheres in solution. In order to manipulate microspheres for two-dimensional or three-dimensional scanning imaging, mechanical devices or other means have been developed to mount the microspheres and to improve the imaging process so that the microspheres can rapidly scan the sample plane over a controlled distance above the sample surface. A very suitable mechanical scaffold for microspheres is an Atomic Force Microscope (AFM) cantilever: the microsphere is fixed at the front part of the cantilever, and the microsphere non-contact scanning imaging can be realized by utilizing high-precision mechanical control of an AFM system.
At present, the microsphere scanning system has few reports and is mainly used for super-resolution microscopic optical characterization, for example, CN102735878A discloses a microsphere combined with an AFM feedback mechanism, and any region of a sample is observed through a scanning method to obtain a larger field of view. Up to 2021, ga š par ć et al demonstrated that mechanically supported microspheres can improve the resolution of raman spectral scan images (Applied Surface Science, DOI: 10.1016/j. Apsusc. 2021.149036). However, their experimental design uses a mechanically supported vertically connected tapered fiber with a soft texture to connect the microspheres, which does not support contact mode scanning well, and more importantly, they also lack information on the application of microspheres to fluorescence emission spectroscopy imaging. In theory, based on the principle that the microsphere can focus and strengthen incident light, the microsphere-assisted super-resolution optical technology can also improve the resolution of scanning photocurrent imaging. However, the technology has not reported a role in photocurrent test characterization, in particular, the dielectric microsphere is utilized to improve the resolution of scanning photocurrent imaging, so as to realize the aspect of microsphere-assisted high-resolution scanning photocurrent imaging.
Disclosure of Invention
The invention aims at providing a preparation method of a micro-cantilever-microsphere probe, which uses an Atomic Force Microscope (AFM) cantilever as a bracket to fix microspheres.
Specifically, a micro-operation system with a three-dimensional high-precision displacement table is used for bonding and fixing the microspheres: fixing an AFM micro-cantilever on a three-dimensional high-precision displacement table through a substrate medium, smearing an adhesive on the end part of the AFM micro-cantilever through fuzz, and then adsorbing transparent medium microspheres on the adhesive on the end part of the AFM micro-cantilever through fuzz to ensure that the transparent medium microspheres are tangent to the end part of the AFM micro-cantilever on a projection surface, so as to prepare the micro-cantilever-microsphere probe.
Further, the adhesive is selected from non-solid Polydimethylsiloxane (PDMS) or ultraviolet curing adhesive.
Further, the transparent medium microsphere is a silicon dioxide microsphere with the particle size of 5-50 microns; preferably having a particle size of 5 microns to 10 microns.
In one embodiment of the invention, the microspheres are adhesively immobilized using a conventional three-dimensional micro-nano mobile console operating system in combination with an optical microscope viewing system: and fixing the AFM micro-cantilever on the micro-nano mobile console through a substrate medium. The microsphere powder was removed and scattered onto a region of the fragment. In another area of the slide, some adhesive is applied with tweezers. The motion console is adjusted so that the tip portion of the AFM microcantilever touches the adhesive, after which the adhesive-bonded microcantilever is lifted off. The nap is fixed on a micro-nano mobile console through a substrate medium, then the microsphere area is moved into the view field of an optical microscope, microspheres with proper size and good morphology are selected, and the microspheres are adsorbed by utilizing the electrostatic force of the hair. Aiming at the position where the needle tip is to be placed, and using non-solid PDMS or ultraviolet curing glue to contact and bond the small ball with the tip of the micro-cantilever. And observing and screening the AFM micro-cantilever with the fixed microsphere lens under a microscope objective.
The second purpose of the invention is to apply the micro-cantilever-microsphere probe to the construction of a super-resolution Raman/fluorescence/photocurrent two-dimensional scanning imaging combined characterization system.
The combined characterization system comprises a confocal Raman spectrometer and atomic force microscope combined system, and the micro-cantilever-microsphere probe is used as a micro-cantilever in atomic force test, so that two-dimensional/three-dimensional scanning spectrum imaging can be realized.
In one embodiment of the invention, the confocal raman spectrometer is used in combination with an atomic force microscope system as a commercial confocal raman spectrometer (WITec Alpha300 RA) system with an upgrade to atomic force microscope options.
Further, the combined characterization system also comprises an external photocurrent testing module, wherein the external photocurrent testing module comprises a voltage current source meter, a current amplifier and a computer analysis unit, and the voltage current source meter, the current amplifier and the computer analysis unit are connected through a circuit; the voltage current source meter is connected with a sample holder of a confocal Raman spectrometer and atomic force microscope combined use system. For the photoelectric micro-nano device, the electrode of the device is connected with an external circuit, and a picoampere-level small signal test can be realized by combining the chopping and alternating current phase-locked amplification technology, and the direct current/alternating current photocurrent response is detected to obtain scanning photocurrent imaging.
The existing high-efficiency characterization combined system combining Raman, fluorescence and atomic force testing functions comprises a Raman laser, an atomic force laser, an optical fiber coupler, a confocal microscope, a Raman spectrometer, a grating, a CCD detector, a signal receiving and signal feedback main controller, a position detector, a high-precision ceramic piezoelectric scanning table, a three-dimensional large-range full-automatic mechanical displacement table, computer and data analysis software, an active vibration-proof workbench and the like. In an atomic force microscope, the working principle of the micro-cantilever is to change the vibration state of the beam body under the action of external excitation, and the change of the amplitude and resonance frequency is used for reflecting the measured physical magnitude. When atomic force which varies with distance is generated between the probe and the sample of the micro-cantilever, the cantilever deflects correspondingly, and the position deviation can be detected by a laser deflection test method. The light reflected by the micro-cantilever is displaced, the receiver receives the changed signal, and finally the shape information of the sample surface is obtained according to the corresponding relation between the force and the distance. Above the cantilever, an objective lens may be placed to obtain optical spectral information of the sample at the same time. In the invention, the micro-cantilever is used as a bracket, and the microsphere is glued and fixed at the outer end of the micro-cantilever of the AFM, namely, the micro-cantilever in the original atomic force test is changed into a micro-cantilever-microsphere probe, and the original components such as signal transmission, signal processing and signal feedback are connected and combined into the original characterization system. According to the operation mode of the atomic force microscope, the high-precision three-dimensional piezoelectric scanning table of the sample is combined, and two-dimensional/three-dimensional scanning spectrum imaging can be realized. Further, for optoelectronic micro-nano devices, the device electrodes can be connected to external circuitry through conventional sample holders. Therefore, the picoampere-level small signal test can be realized by externally connecting a photocurrent test module and combining the chopping and alternating current phase-locked amplification technology, and the direct current/alternating current photocurrent response can be detected. The photocurrent signal is fed back to the main body controller and the testing software, and the scanning photocurrent imaging with high spatial resolution is generated by combining the real-time position information of the scanning table. Finally, the microsphere-assisted super-resolution Raman/fluorescence/photocurrent two-dimensional scanning imaging combined characterization system is obtained.
The method for carrying out real-time imaging and characterization on the sample by adopting the super-resolution Raman/fluorescence/photocurrent two-dimensional scanning imaging combined characterization system comprises the following steps:
in the spectrum/atomic force combined system, the micro-cantilever-microsphere probe is introduced between the laser irradiation light path objective lens and the sample, so that the microsphere is used as an additional lens in the light path to further focus the incident light. The three dimensions of the distance and the position of the microsphere relative to the surface of the sample are adjustable by adopting a micro-nano feedback control method of atomic force; the distance between the microsphere and the sample can be regulated and controlled through a feedback loop of the system. The microsphere-sample distance is controlled in the microsphere focal length range, the optical diffraction limit of near field 200nm is broken through, and super-resolution optical microscopic imaging and Raman/fluorescence spectrum single-point signal enhancement of the sample can be realized; the ceramic piezoelectric scanning table for placing the sample is matched, so that two-dimensional scanning characterization of the sample below the microsphere is realized, and multi-region, full-view-field, super-resolution optical microscopic imaging and super-resolution Raman/fluorescence spectrum scanning imaging of the micro-nano sample are realized. By connecting the optoelectronics externally to a current-voltage source meter and current amplifier, and then to the signal receiving process controller of the system, small photocurrent signals generated when laser light impinges on the sample can be detected. Therefore, the optical current single-point signal enhancement and super-resolution optical current scanning imaging can be further realized.
Compared with the prior art, the super-resolution Raman/fluorescence/photocurrent two-dimensional scanning imaging combined characterization system provided by the invention has the advantages that:
(1) The micro-manipulation technology designed by self is utilized to fix the microsphere on the atomic force needle point, so that the key technical problem that the microsphere-assisted super-resolution optical technology is applied to photocurrent test is solved;
(2) The microsphere-assisted Raman/fluorescence/photocurrent two-dimensional scanning combined characterization system is realized for the first time at low cost, so that more comprehensive super-resolution imaging application is obtained;
(3) The combined characterization system is widely applied, for example, for photoelectric devices of two-dimensional material heterojunction, and can characterize the correlation between microstructure and photocurrent so as to analyze a mechanism, thereby providing important information for device structure optimization and performance improvement.
According to the invention, the microsphere is supported by the atomic force micro-cantilever bracket, the microsphere lens is added in a system light path, super-resolution focusing light spots are generated after passing through transparent medium microspheres, and the accurate control of the microsphere lens is realized by means of an atomic force microscope signal feedback and control system, so that diffraction limit resolution exceeding that of an original system, namely super-resolution Raman/fluorescence/photocurrent imaging, is finally realized on Raman, fluorescence spectrum and photocurrent scanning imaging. The super-resolution spectrum and photocurrent imaging method provided by the invention is economical and efficient, and provides a reliable tool for comprehensively understanding and revealing the photoelectric characteristics of materials.
Drawings
FIG. 1 shows the results of the preparation of the microcantilever-microsphere probe of example 1.
Fig. 2 is a schematic diagram of a microsphere-based super-resolution raman/fluorescence/photocurrent two-dimensional scanning imaging combined characterization system in example 1. Wherein: the device comprises a microscope objective lens 1, a three-dimensional high-precision ceramic piezoelectric scanning table 2, a white light illumination light source 3, a Raman laser 4, an image sensing camera 5, a three-dimensional large-range full-automatic mechanical displacement table 6, an active vibration-proof workbench 7, an atomic force infrared laser 8, a spot position detector formed by a photodiode 9, a microsphere 10, a micro-cantilever fixer 11, a micro-cantilever 12, a test sample/device 13, a current-voltage source meter 14, a current amplifier 15 and computer and data analysis software 16.
Fig. 3 is a schematic diagram of scanning photocurrent imaging in example 1.
FIG. 4 is a comparison of the resolution of Raman scan imaging of the peaks of sample A1g of molybdenum disulfide under the four configuration conditions of example 1.
FIG. 5 is a comparison of scanning imaging resolution of fluorescence peaks of tungsten diselenide samples under the four configuration conditions in example 1.
FIG. 6 is a comparison of the photocurrent signal intensity of the 20-fold objective lens of example 1 with the microsphere probe.
Fig. 7 is a comparison of photocurrent scanning imaging resolution of a molybdenum disulfide device under the four configuration conditions of example 1.
Description of the embodiments
Exemplary embodiments of the present disclosure will be described in more detail below with reference to the accompanying drawings. While exemplary embodiments of the present disclosure are shown in the drawings, it should be understood that the present disclosure may be embodied in various forms and should not be limited to the embodiments set forth herein. Rather, these embodiments are provided so that this disclosure will be thorough and complete, and will fully convey the scope of the disclosure to those skilled in the art.
Examples
In the embodiment, the microspheres with diameters of 10 mu m and 50 mu m are adhered to an AFM cantilever by using ultraviolet curing adhesive (NOA 68T,Norland Products Inc), so that a micro-cantilever-microsphere probe is obtained, and accurate control of the microspheres is realized.
Firstly, selecting an AFM micro-cantilever with the length of tens of micrometers, the thickness of micrometers and flat side surfaces, fixing the AFM micro-cantilever on a glass slide and mounting the AFM micro-cantilever on a three-dimensional high-precision displacement table; in this example, a tip-less silicon AFM cantilever provided by NANOSENSORS ™ was used, having a force constant of 42N/m and a thickness of about 3 μm. The nap was adhered to another slide using a nap having a diameter of several tens to several hundreds micrometers by means of an adhesive tape, and then was subjected to a microscopic procedure to dip a small amount of uv curable adhesive (NOA 68T,Norland Products Inc). The napped slide is mounted to another three-dimensional high precision displacement stage. And then controlling the two transfer tables under an optical microscope, and enabling the fuzz dipped with the ultraviolet curing adhesive to contact the side surface of the end part of the AFM micro-cantilever, so that a small amount of ultraviolet curing adhesive is attached to the AFM micro-cantilever.
Next, transparent medium microspheres were scatter deposited on a glass slide, in this example silica medium microspheres were used. And then another nap with the diameter of tens to hundreds of micrometers is used, the nap is adhered to another glass slide through an adhesive tape, the nap is contacted with the microspheres positioned on the glass slide, and the dried microspheres are easily adsorbed on the nap through electrostatic effect due to friction between the nap and the glass slide, so that the picking of the microspheres by the nap is completed. Further, the fine wool glass slide attached with the microspheres is replaced by a filament glass slide dipped with ultraviolet curing glue and fixed on a three-dimensional high-precision transfer table. Similar to the step of applying the uv curable glue to the AFM microcantilever, the microspheres were glued to the AFM microcantilever in the region with the uv curable glue (shown in fig. 1 b) by manipulating the two transfer stations with the AFM microcantilever and the microsphere nap immobilized under an optical microscope. Finally, the joint of the microsphere and the needle point is irradiated by ultraviolet light for about 2 hours, the ultraviolet glue is cured, and the AFM microcantilever-microsphere needle point is manufactured (shown in c and d in fig. 1).
The dielectric microsphere is adhered to a specific position of the micro-cantilever by the method of the invention, so that when the atomic force laser is applied to the micro-cantilever, the Raman laser irradiates the center of the dielectric microsphere. As shown in fig. 1, the positions of the ball bonds in a are right below the micro-cantilevers, so that the light path is blocked, and the target function cannot be realized; c is the AFM micro-cantilever-microsphere pinpoint which is successfully manufactured and is adhered with the microsphere with the diameter of 10 microns; d is the AFM microcantilever-microsphere tip with 50 micron diameter microspheres attached successfully. In the case of such microsphere position, when laser light of an atomic force microscope system for positioning is irradiated at the center of the cantilever, raman laser light may be irradiated to the microsphere center position.
As shown in fig. 2, in this example, the experimental setup of the microsphere-assisted high resolution scanning spectroscopy/photocurrent microscopy system was based on a commercial confocal raman spectrometer (WITec Alpha300 RA) system with an upgrade to the atomic force microscopy option. YAG laser with 532 nm frequency multiplication Nd is used as an excitation light source for measurement by the Raman laser 4, and infrared ultra-light emitting diode laser with 1050 nm wavelength is used as an excitation light source for an atomic force microscope system by the atomic force infrared laser 8; the microscope objective 1 used a x 20 objective (Zeiss EC epilan, na=0.4), a x 50 objective (Zeiss LD EC Epiplan-Neofluar Dic, na=0.55) and a x 100 objective (Zeiss LD EC Epiplan-Neofluar Dic, na=0.9).
The prepared micro-cantilever-microsphere probe is arranged on a micro-cantilever fixer 11, and a three-dimensional large-range full-automatic mechanical displacement table 6 and a three-dimensional high-precision ceramic piezoelectric scanning table 2 stepper motor are used for large-range and accurate movement in three directions (minimum stroke: 1 micron in X and Y directions and 1 micron in Z direction). The laser of the atomic force microscope system is incident on the center of the micro-cantilever and reflected to the spot position detector 9 constituted by the photodiode. The micro-cantilever-microsphere probe is adjusted to the focusing light path of the objective lens in the Z direction by the adjustment procedure commonly used for atomic force microscopy; after the micro-cantilever position is adjusted by the detector in the X and Y directions, the position of the cantilever in the XY direction is fixed during scanning. The test sample/device 13 is placed on a three-dimensional ceramic piezoelectric scanning stage 2 that can be raster scanned with a lateral (X and Y directions) resolution of 1 nm and a longitudinal (Z direction) resolution of 10 nm. By moving the stage in 1 micron units in the Z direction, the effect of the distance (Δd) between the medium microsphere and the sample can be explored to find the focus position or the position where the signal is strongest. The system can acquire the feedback adjustment of the atomic force microscope in the vertical direction so as to monitor the distance and the interaction force between the medium microsphere and the sample. Once the distance or force reaches the set point, the sample stage stops moving. Thus, microsphere-assisted spectroscopy/photocurrent scanning can be achieved using either a "contact mode" or a "constant height mode" according to atomic force microscopy principles.
In the test procedure, the laser beam passes through the silica medium microsphere, converges the incident light, and forms a focus on the backlight side (sample surface) of the medium microsphere by the optical nanojet effect. When obtaining raman/photoluminescence scan images, raman/photoluminescence spectra are collected using a high-throughput confocal microscope/raman spectrometer combination and signals are captured with a high-sensitivity image sensing camera 5. When photocurrent imaging is performed, as shown in fig. 3, a device to be tested (such as a photoelectric micro-nano device) can connect a device electrode with an external circuit through a conventional sample holder; an external voltage (zero voltage for self-driven optoelectronic devices) is applied through a current-voltage source meter 14 and connected to small signal test equipment, including a low noise current amplifier 15 (Femto DLPCA-200) and a built-in lock-in amplifier; the scanned spectrum and photocurrent signals are detected and visualized by a Witec computer and dedicated software tools. After the sample is irradiated by light, weak current generated by the device is amplified by a current amplifier (DLPCA-200), and then is subjected to subsequent processing by a phase-locked amplifier inherent in the Alpha300 RA microscope system, and the generated amplified noise reduction signal is received by the system and displayed on a computer software interface, so that excitation and reception of the light current signal are realized.
As shown in fig. 4, four raman scanning imaging results under the configuration conditions are shown, wherein the four raman scanning imaging results are respectively 20-fold mirror matched with 10 mu m silicon dioxide medium microsphere (a), 100-fold mirror (b), 50-fold mirror (c) and 20-fold mirror (d), the scanning step length is 100 nm, and the test sample is molybdenum disulfide (MoS 2 ) The incident laser power was 2 mW, and the signal collection time (integration time) at each point at the time of scanning was 0.5 s. First compare a with b, c, d in the figure: without the microspheres, the 20-fold mirror scan resulted in an image that was very blurred and almost impossible to compare with the optical photograph of the sample. Extracting the signal intensity line segment distribution at the edge of the sample, plotting the edge spread function (e, f, g, h in FIG. 4), since the signal intensity follows the lineThe line segment cannot form an effective low-to-high trend, so that the half-width of the line segment cannot be calculated, and the resolution of the line segment is difficult to determine. After the microspheres are added, the intensity distribution and the sample profile of the raman spectrum signals of the samples corresponding to different thicknesses can be obviously seen in fig. 4 a; by the edge diffusion function resolution calculation method (e in fig. 4), the resolution in this case reaches 213 nm, the resolution achieved by 100 times of the mirror is higher than that achieved by 295 nm, and the resolution of 375 nm can only be achieved by 50 times of the mirror under the same condition, which indicates that the microsphere can improve the quality of raman scanning imaging and reach super-resolution characterization beyond the limit of the system itself (under 100 times of the mirror).
Similar to raman spectroscopy, this example also investigated contrast in fluorescence spectroscopy scanning imaging resolution under four different configurations. As shown in fig. 5, the scanning step length is 100 nm, the test sample is tungsten diselenide (WSe) 2 ) The incident laser power was 1 mW, and the signal collection time (integration time) at each point at the time of scanning was 0.1 s. Comparing a with b, c and d in fig. 5, the image obtained by 20 times mirror scanning is very blurred without microspheres, and the image can not be compared with the optical photograph of the sample almost; the signal intensity line segment distribution at the edge of the sample is extracted, the edge diffusion function is drawn, and the calculated resolution is 1718 and nm. The profile of the sample and the intensity distribution of the fluorescence spectrum signal can be seen more clearly from fig. 5 a after the microsphere is added, and the resolution in this case reaches 412 and nm through resolution calculation as shown in fig. 5 e, and the resolution achieved by the 100-fold mirror is numerically exceeded (582 and nm), and the 50-fold mirror under the same condition can only achieve 613 and nm resolution, which also proves the feasibility of the microsphere in fluorescence spectrum scanning application.
The enhancement of the photocurrent by the microspheres was compared and shown in fig. 6 as the photocurrent signal intensity with and without microspheres at a 20-fold mirror. At the time of testing, 10 s is a periodic switching laser, where the time to turn the laser off and on is 5 s, and the results of several cycles are finally collected for comparison. As can be seen from fig. 6 a, the signal intensity is improved by about 2 times after the microspheres are provided, and the applied external bias voltage value is 0V, which proves that the microspheres can improve the photocurrent signal intensity. After changing the applied bias voltage value, as shown in fig. 6 b, the bias voltage value increases to 0.5 and V, and the photoelectric current value also increases significantly, but since the current is mainly contributed by the applied bias voltage, the current generated by illumination only occupies a small part, so that the signal intensity after the microsphere is added is not significantly improved.
As shown in fig. 7, the photo-current scanning imaging results of the same region of one molybdenum disulfide device under four configuration conditions (respectively, 20 times mirror, 50 times mirror, 100 times mirror and 20 times mirror matched with 10 μm silica medium microsphere) are presented. The scanning experiment was performed under zero bias, and the photocurrent was mainly contributed by the contact potential between the metal electrode and the device, so the photocurrent was mainly generated at the location where the metal electrode and the device contacted. As the NA value of the objective lens increases (or magnification) the resolution of the photocurrent scan image increases stepwise (shown as a-f in fig. 7). Whereas a 20-fold mirror equipped with silica medium microspheres 10 μm in diameter had the highest photocurrent scan image resolution (shown as g and h in fig. 7). The above results demonstrate the feasibility of microsphere-assisted high-resolution photocurrent scanning images, based on which the detailed distribution of the electrode region photocurrent generating region can be further demonstrated.
The above is merely exemplary embodiments of the present invention, but the scope of the present invention is not limited thereto, and any changes or substitutions easily conceivable by those skilled in the art within the technical scope of the present invention should be included in the scope of the present invention. Therefore, the protection scope of the invention is subject to the protection scope of the claims.
Claims (9)
1. The micro-cantilever-microsphere probe is characterized by comprising an atomic force microscope cantilever and transparent medium microspheres, wherein the transparent medium microspheres are connected to the end parts of the atomic force microscope cantilever and tangent to the end parts of the atomic force microscope cantilever on a projection surface.
2. The method for preparing the micro-cantilever-microsphere probe according to claim 1, wherein an atomic force microscope cantilever is fixed on a three-dimensional high-precision displacement table through a substrate medium, adhesive is smeared on the end part of the atomic force microscope cantilever by naps, and then the naps are used for adsorbing the transparent medium microsphere to be adhered to the adhesive on the end part of the atomic force microscope cantilever, so that the transparent medium microsphere is ensured to be tangent to the end part of the atomic force microscope cantilever on a projection surface.
3. The method for preparing a microcantilever-microsphere probe according to claim 1, wherein the nap adsorbs the transparent medium microsphere by electrostatic adsorption.
4. The method for preparing a microcantilever-microsphere probe according to claim 1, wherein the transparent medium microsphere is a silica microsphere with a particle size of 5-50 microns.
5. The method of preparing a microcantilever-microsphere probe according to claim 1, wherein the adhesive is a non-solid polydimethylsiloxane or an ultraviolet curable glue.
6. A super-resolution raman/fluorescence/photocurrent two-dimensional scanning imaging combined characterization system, comprising a confocal raman spectrometer and atomic force microscope combined system, wherein the combined system comprises the micro-cantilever-microsphere probe according to claim 1 and a photocurrent testing module.
7. The system of claim 6, wherein the microcantilever-microsphere probe is disposed on a mobile platform below the objective lens.
8. The system of claim 6, wherein the photocurrent testing module comprises a voltage current source meter, a current amplifier, and a computer analysis unit, the voltage current source meter, the current amplifier, and the computer analysis unit being connected by a circuit; the voltage current source meter is connected with the sample to be measured.
9. Use of the system of any of claims 6 to 8 for photo current imaging of a photovoltaic device.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202311312671.7A CN117434303A (en) | 2023-10-11 | 2023-10-11 | Super-resolution Raman/fluorescence/photocurrent two-dimensional scanning imaging combined characterization system based on micro-cantilever-microsphere probe |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202311312671.7A CN117434303A (en) | 2023-10-11 | 2023-10-11 | Super-resolution Raman/fluorescence/photocurrent two-dimensional scanning imaging combined characterization system based on micro-cantilever-microsphere probe |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CN117434303A true CN117434303A (en) | 2024-01-23 |
Family
ID=89554493
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN202311312671.7A Pending CN117434303A (en) | 2023-10-11 | 2023-10-11 | Super-resolution Raman/fluorescence/photocurrent two-dimensional scanning imaging combined characterization system based on micro-cantilever-microsphere probe |
Country Status (1)
| Country | Link |
|---|---|
| CN (1) | CN117434303A (en) |
-
2023
- 2023-10-11 CN CN202311312671.7A patent/CN117434303A/en active Pending
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| US5894122A (en) | Scanning near field optical microscope | |
| US6850323B2 (en) | Locally enhanced raman spectroscopy with an atomic force microscope | |
| JP5292128B2 (en) | Scanning probe microscope and sample observation method using the same | |
| US5548113A (en) | Co-axial detection and illumination with shear force dithering in a near-field scanning optical microscope | |
| JP5033609B2 (en) | Scanning probe microscope and sample observation method using the same | |
| JP2004533604A (en) | Non-aperture near-field scanning Raman microscopy using reflection-scattering geometry | |
| US5859364A (en) | Scanning probe microscope | |
| CN102829961A (en) | Nano-optics multi-parameter measurement platform | |
| US20060043290A1 (en) | Scanning probe microscopy cantilever holder and scanning probe microscope using the cantilever holder | |
| KR101108022B1 (en) | Method and apparatus for enhanced nano-spectroscopic scanning | |
| CN111665374B (en) | Optical fiber probe based on quantum dots and detection system thereof | |
| CN110057751B (en) | Apparatus and method for fabricating optical particle probe | |
| JP4498081B2 (en) | Scattering near-field microscope and measuring method thereof | |
| CN113008849B (en) | Ultraviolet-near infrared broadband micro-region photoluminescence spectrum testing device | |
| Celebrano et al. | Hollow-pyramid based scanning near-field optical microscope coupled to femtosecond pulses: A tool for nonlinear optics at the nanoscale | |
| CN112525884A (en) | Ultra-micro Raman spectrum detection device | |
| CN117434303A (en) | Super-resolution Raman/fluorescence/photocurrent two-dimensional scanning imaging combined characterization system based on micro-cantilever-microsphere probe | |
| US8296861B2 (en) | Polarization-modulated tip enhanced optical microscope | |
| CN116593738A (en) | Light-focusing detection microscope and application thereof | |
| US20100154084A1 (en) | Method and apparatus for performing apertureless near-field scanning optical microscopy | |
| Ramos et al. | Reflection-mode, confocal, tip-enhanced Raman spectroscopy system for scanning chemical microscopy of surfaces | |
| CN111721750A (en) | Method and device for improving non-contact mode TERS signal of atomic force microscope | |
| JP4202076B2 (en) | Scattering near-field microscope | |
| JP4448534B2 (en) | Scanning probe microscope | |
| CN217385551U (en) | Surface enhanced Raman atomic force microscope system |
Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| PB01 | Publication | ||
| PB01 | Publication | ||
| SE01 | Entry into force of request for substantive examination | ||
| SE01 | Entry into force of request for substantive examination |