CN2392189Y - Scanning channel telscope work function information imaging device - Google Patents
Scanning channel telscope work function information imaging device Download PDFInfo
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- CN2392189Y CN2392189Y CN 99250257 CN99250257U CN2392189Y CN 2392189 Y CN2392189 Y CN 2392189Y CN 99250257 CN99250257 CN 99250257 CN 99250257 U CN99250257 U CN 99250257U CN 2392189 Y CN2392189 Y CN 2392189Y
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- amplifier
- signal
- work function
- function information
- signal generator
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- 238000003384 imaging method Methods 0.000 title claims abstract description 12
- 239000000523 sample Substances 0.000 claims abstract description 19
- 238000009434 installation Methods 0.000 claims description 10
- 239000000919 ceramic Substances 0.000 description 2
- 238000004441 surface measurement Methods 0.000 description 2
- 230000005641 tunneling Effects 0.000 description 2
- 230000007812 deficiency Effects 0.000 description 1
- 238000010586 diagram Methods 0.000 description 1
- 238000000605 extraction Methods 0.000 description 1
- 238000001914 filtration Methods 0.000 description 1
- 239000000463 material Substances 0.000 description 1
- 230000010363 phase shift Effects 0.000 description 1
- 230000005610 quantum mechanics Effects 0.000 description 1
- 238000012876 topography Methods 0.000 description 1
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Abstract
The utility model relates to a work function information imaging device of a scanning channel microscope, which comprises a scanner with a probe, an amplifier, a proportional integrator, an analog to digital converter, a digital to analog converter, a computer device, a signal generator and a phase locking amplifier, wherein one input end of the phase locking amplifier is connected with the output end of the logarithmic amplifier A2, the other input end of the phase locking amplifier is connected with the signal generator, an output signal with work function information of the signal generator is connected with the analog to digital converter ADC, and the output end of the signal generator is simultaneously connected with the input end of a high-voltage amplifier HA. The utility model has the advantages that the work function information imaging device not only can obtain the fine structures of surfaces, but also can measure the work function information of surface elements.
Description
The utility model relates to the scan-probe imaging technique, is based on the work function information imaging device that scanning tunnel microscope is set up.
In the prior art, scanning tunnel microscope can obtain the resolution picture of sample surfaces nanometer and even atomic scale with its superior resolution, can carry out observational study to surface structure, but can not calibration sample surface-element kind and distribution, yet according to tunnel effect principle as can be known: the tunnel current between probe and the sample not only reflects the structure of sample surfaces, has also comprised the work function information of sample element simultaneously.
In order to overcome above-mentioned deficiency, the purpose of this utility model is based on scanning tunnel microscope and adopts technology such as modulation to tunnel current, demodulation, extraction work function information, set up and a kind ofly can obtain surperficial fine structure, but the also scanning tunnel microscope work function information imaging device of surface measurements element work function information.
To achieve these goals, the technical solution of the utility model: comprise the scanner, amplifier, proportional integral device, digital-to-analogue, analog to digital converter and the computer installation that carry probe, sample ground connection wherein, prime amplifier A
1In-phase end is connected to tunnel bias voltage V
bAnode, its out-phase end connects the current signal from probe tip, and its output end signal one tunnel and reference current Ir are through error amplifier A
3Be connected to the proportional integral device; Another road meets logarithmic amplifier A
2, tunnel bias voltage V
bNegative terminal and sample are altogether, the input termination proportional integral device of high-voltage amplifier HA, output terminal is connected to the Z arm of scanner, the X of described scanner, Y arm output signal are changed DAC from the scan control terminal number mould of computer installation, proportional integral device output termination analog to digital converter ADC is characterized in that: at logarithmic amplifier A to the acquisition controlling end of computer installation
2After establish a lock-in amplifier, add a signal generator before the high-voltage amplifier HA, an input end of lock-in amplifier is connected to described logarithmic amplifier A
2Output terminal, another input end is connected with signal generator, its output signal that has work function information is delivered to analog to digital converter ADC, the modulation signal of described signal generator is connected with the input end of high-voltage amplifier HA simultaneously;
Described logarithmic amplifier A
2Output signal is the input signal of Hi-pass filter in the lock-in amplifier, describedly comes the reference signal of automatic signal generator to be connected to the input end of phase shifter in the lock-in amplifier, amplifier A in the described lock-in amplifier
5Output terminal links to each other with described analog to digital converter ADC; Come the modulation signal of automatic signal generator and from the feedback signal of proportional integral device respectively through resistance R
1And R
2Be connected with the out-phase end of described high-voltage amplifier HA; The frequency modulating signal of described signal generator is greater than the cutoff frequency in loop, less than scanner response cutoff frequency, identical with the frequency of reference signal, the cutoff frequency in its loop is adjustable in the 1KHz-10KHz scope, the scanner cutoff frequency is less than 50KHz, the frequency of reference signal and modulation signal frequency to be the 5KHz-25KHz scope adjustable.
The utlity model has following advantage:
The utility model has utilized electron tunneling principle in the quantum mechanics and tunnel current to rely on the relations I ∝ V of material work function
bExp (1.025 Φ
1/2S), on the basis of scanning tunnel microscope, developed the function of work function information imaging, scanning tunnel microscope had both been had can observe surperficial fine structure, but the also function of surface measurements element and distribution thereof.
Description of drawings
Fig. 1 is a structural drawing of the present utility model.
Fig. 2 is the lock-in amplifier circuit theory diagrams in the utility model.
Fig. 3 is the connection layout that modulation signal and high pressure amplify HA in the utility model.
Below in conjunction with accompanying drawing and principle of work thereof the utility model is described in further detail.
As shown in Figure 1, comprise piezoelectric scanner, amplifier, proportional integral device, digital-to-analogue, analog to digital converter and the computer installation that carries probe.Sample ground connection wherein, tunnel bias voltage V
bWith sample altogether, tunnel bias voltage V
bBe added in prime amplifier A
1In-phase end is from the current signal and the prime amplifier A of needle point
1The out-phase end connects, prime amplifier A
1Output signal one tunnel and reference current I
rTogether through error amplifier A
3Be connected to the proportional integral device, another road meets logarithmic amplifier A
2The output terminal of its proportional integral device is connected to the Z arm of scanner through high-voltage amplifier HA, be connected to the analog to digital converter ADC of computer installation acquisition controlling end simultaneously, the X of described scanner, Y arm input signal are from the digital to analog converter DAC of computer installation scan control end, and described proportional integral device output termination analog to digital converter ADC is to the acquisition controlling end of computer installation; Add a signal generator and lock-in amplifier in addition, the input end that the output one tunnel of its signal generator meets high-voltage amplifier HA is as modulation signal, and another road connects lock-in amplifier, described logarithmic amplifier A
2Output terminal to lock-in amplifier.
As shown in Figure 2, lock-in amplifier shown in comprises wave filter, amplifier, phase shifter and phase-sensitive detector (PSD).Described logarithmic amplifier A
2Output signal is the input signal of lock-in amplifier, is connected to selective amplifier A through Hi-pass filter
4, the reference signal of described signal generator output is another input signal of lock-in amplifier, connects the input end of phase shifter, phase shifter and selective amplifier A
4Output be respectively the input of phase-sensitive detector (PSD), the output signal of phase-sensitive detector (PSD) is connected to amplifier A by low-pass filter through resistance R
5, amplifier A
5Out-phase input and output terminal cross-over connection one adjustable resistance R
F1The in-phase end resistance grounded.The lock-in amplifier output terminal links to each other with described analog to digital converter ADC.
As shown in Figure 3, come the modulation signal of automatic signal generator and from the feedback signal of proportional integral device respectively through resistance R
1And R
2Join its in-phase end leakage resistance R with the out-phase end of described high-voltage amplifier HA
3Ground connection, its in-phase end and output terminal is cross-over connection one adjustable resistance R also
F2
The frequency modulating signal of described signal generator is greater than the cutoff frequency in loop, response cutoff frequency less than the scanner piezoelectric ceramics, identical with the frequency of reference signal, the cutoff frequency in the described loop of present embodiment is 5KHz, the response cutoff frequency of described scanner piezoelectric ceramics is 40KHz, and reference signal frequency and frequency modulating signal are 10KHz.
Principle of work of the present utility model is:
Under the constant current scan pattern, give the sinusoidal modulation signal of superpose on the scanner Z arm high pressure fixed frequency and amplitude, its frequency is higher than the loop cutoff frequency, when making needle point rely on tunnel spacing variation, be subjected to the modulation of modulation signal again, modulating current is with size variation, and its frequency and modulation signal are with frequently, amplitude is relevant with the size of work function value, utilizes lock-in amplifier to extract the modulated current signal relevant with work function information; By tunneling effect as can be known, modulating current and work function information exponent function relation are extracted signal and the proportional relation of work function numerical value by making, and modulated current signal must be through logarithmic amplifier A
2Lock-in amplifier is sent in linearization again; Signal is through high-pass filtering and selective amplifier A
4Later input as phase-sensitive detector (PSD), phase-sensitive detector (PSD) is equivalent to a multiplier, two input signals are respectively the current signal after modulation signal and the modulation, phase-sensitive detector (PSD) output is not only relevant with its amplitude of two input signals, but also it is relevant with the phase differential between two input signals, when the phase differential of these two signals is pi/2, output valve is maximum and only proportional with the amplitude of input signal, therefore, on the path of reference signal, insert a phase-shift circuit, in order to adjust two phase differential between the input signal is pi/2, make output and phase-independent, only relevant with the input signal amplitude, like this, the output of phase-sensitive detector (PSD) have only direct current signal (being difference frequency signal) and frequency higher with the frequency signal; For making image data stable, then low-pass filter is sent in the output of phase-sensitive detector (PSD) and filtered high-frequency signal, like this, the output of lock-in amplifier is the dc signal for being directly proportional with the work function information value just; Analog to digital converter ADC gathers the output signal of lock-in amplifier, by software the form of the data of computer acquisition with image is showed, and like this, just can utilize image to represent work function information.Scanning tunnel microscope work function information image-forming principle that Here it is.
In addition, utilize the two-way acquisition channel, promptly when certain point of scanning, gather this pattern information earlier, gather work function information amplitude more respectively to surface topography information and work function information acquisition.Collection finishes to move to down and a bit continues to gather; The pattern information and the work function information of gathering are the data of two groups of correspondences, and the fluctuating on the size reflection surface of pattern information is represented with the 3-D scanning line; The size of corresponding work function information is then used color showing, and final image had both reflected the fluctuating of pattern, showed the size of work function again.
The described signal generator of present embodiment adopts ORTEC Brookdeal 5012F type, and other adopts PAR
TMModel 128 lock-in amplifiers, proportional integral device and amplifier are prior art.
Claims (4)
1. the work function information imaging device of a scanning tunnel microscope comprises the scanner, amplifier, proportional integral device, digital-to-analogue, analog to digital converter and the computer installation that carry probe, sample ground connection wherein, prime amplifier A
1In-phase end is connected to tunnel bias voltage V
bAnode, its out-phase end connects the current signal from probe tip, and its output end signal one tunnel and reference current Ir are through error amplifier A
3Be connected to the proportional integral device; Another road meets logarithmic amplifier A2, tunnel bias voltage V
bNegative terminal and sample are altogether, the input termination proportional integral device of high-voltage amplifier HA, output terminal is connected to the Z arm of scanner, the X of described scanner, Y arm output signal are changed DAC from the scan control terminal number mould of computer installation, proportional integral device output termination analog to digital converter ADC is characterized in that: at logarithmic amplifier A to the acquisition controlling end of computer installation
2After establish a lock-in amplifier, add a signal generator before the high-voltage amplifier HA, an input end of lock-in amplifier is connected to described logarithmic amplifier A
2Output terminal, another input end is connected with signal generator, its output signal that has work function information is delivered to analog to digital converter ADC, the modulation signal of described signal generator is connected with the input end of high-voltage amplifier HA simultaneously.
2. according to the work function information imaging device of the described scanning tunnel microscope of claim 1, it is characterized in that: described logarithmic amplifier A
2Output signal is the input signal of Hi-pass filter in the lock-in amplifier, describedly comes the reference signal of automatic signal generator to be connected to the input end of phase shifter in the lock-in amplifier, amplifier A in the described lock-in amplifier
5Output terminal links to each other with described analog to digital converter ADC.
3. according to the work function imaging device of the described scanning tunnel microscope of claim 1, it is characterized in that: come the modulation signal of automatic signal generator and from the feedback signal of proportional integral device respectively through resistance R
1And R
2Be connected with the out-phase end of described high-voltage amplifier HA.
4. according to the work function information imaging device of claim 1,2 or 3 described scanning tunnel microscope, it is characterized in that: the frequency modulating signal of described signal generator is greater than the cutoff frequency in loop, less than scanner response cutoff frequency, identical with the frequency of reference signal, the cutoff frequency in its loop is adjustable in the 1KHz-10KHz scope, the scanner cutoff frequency is less than 50KHz, the frequency of reference signal and modulation signal frequency to be the 5KHz-25KHz scope adjustable.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN 99250257 CN2392189Y (en) | 1999-11-10 | 1999-11-10 | Scanning channel telscope work function information imaging device |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN 99250257 CN2392189Y (en) | 1999-11-10 | 1999-11-10 | Scanning channel telscope work function information imaging device |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CN2392189Y true CN2392189Y (en) | 2000-08-16 |
Family
ID=34035022
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN 99250257 Expired - Fee Related CN2392189Y (en) | 1999-11-10 | 1999-11-10 | Scanning channel telscope work function information imaging device |
Country Status (1)
| Country | Link |
|---|---|
| CN (1) | CN2392189Y (en) |
Cited By (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN1303415C (en) * | 2004-12-28 | 2007-03-07 | 中山大学 | Probe scanning microscope for tunneling loss and measuring method therefor |
| CN102820858A (en) * | 2012-07-31 | 2012-12-12 | 赵烨梁 | High-frequency signal amplifying circuit for scanning tunnel microscope |
| CN109863408A (en) * | 2016-09-19 | 2019-06-07 | 塞威实验室有限责任公司 | Methods, devices and systems for scanning tunneling microscope Control System Design |
-
1999
- 1999-11-10 CN CN 99250257 patent/CN2392189Y/en not_active Expired - Fee Related
Cited By (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN1303415C (en) * | 2004-12-28 | 2007-03-07 | 中山大学 | Probe scanning microscope for tunneling loss and measuring method therefor |
| CN102820858A (en) * | 2012-07-31 | 2012-12-12 | 赵烨梁 | High-frequency signal amplifying circuit for scanning tunnel microscope |
| CN109863408A (en) * | 2016-09-19 | 2019-06-07 | 塞威实验室有限责任公司 | Methods, devices and systems for scanning tunneling microscope Control System Design |
| CN109863408B (en) * | 2016-09-19 | 2022-07-08 | 塞威实验室有限责任公司 | Method, device and system for designing scanning tunnel microscope control system |
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| Date | Code | Title | Description |
|---|---|---|---|
| C14 | Grant of patent or utility model | ||
| GR01 | Patent grant | ||
| C19 | Lapse of patent right due to non-payment of the annual fee | ||
| CF01 | Termination of patent right due to non-payment of annual fee |