Method for preparing electronic crystal on silicon surface by using pulse laser and observation method of electronic crystal

Abstract

The invention discloses a method for preparing an electronic crystal on a silicon surface and an observation method thereof, and the method comprises the steps: enabling nanosecond pulse laser in an ultraviolet band to act on a semiconductor silicon wafer in high vacuum, enabling the pulse laser to form plasma on the silicon surface, enabling the pulse laser to resonate with laser photons on the surface of the plasma to form electron gas, photons and electron gas resonate to form a two-dimensional electron crystal. According to the method, the preparation of the two-dimensional electron crystal on the surface of semiconductor silicon can be realized at normal temperature, and the inventor also utilizes a new reflection Talbot effect imaging method to clearly observe the imaging of various symmetrical structures of the two-dimensional electron crystal; and capturing the transient dynamic balance image of the electronic crystal on the silicon surface by adopting a reflection Talbot effect imaging method. Therefore, an experimental research foundation is laid for high-end research of preparation of an electronic crystal structure at normal temperature, and meanwhile, regulation and control of the electron mobility of a silicon surface material can be realized to promote research and development of silicon-based optoelectronic materials and devices.

Description

Technical Field

[0001] The invention relates to the field of semiconductor science and technology, in particular to a method for preparing electronic crystals on a silicon surface by using ultraviolet nanosecond pulse laser. Background Art

[0002] In the last century, the famous physicist Wigner deduced from the basic principles of quantum mechanics that electronic crystal structures would appear on the surfaces of certain materials. Currently, the preparation of electronic crystals on the surfaces of materials such as liquid helium and semiconductor silicon can only be achieved at low temperatures (4K). Summary of the invention

[0003] The technical problem to be solved by the present invention is to provide a method for preparing electronic crystals on the silicon surface using ultraviolet nanosecond pulse lasers. The method can construct a research platform for preparing electronic crystals on the surface of semiconductor materials. The scientific and technological process adopts a purely physical process and is green and environmentally friendly, which can promote the research and development of silicon-based optoelectronic materials and devices.

[0004] The present invention is achieved as follows: a method for preparing electronic crystals on a silicon surface using ultraviolet nanosecond pulse laser, wherein nanosecond pulse laser in the ultraviolet band is used to act on a semiconductor silicon surface in a high vacuum, a focusing lens is used to regulate the fundamental mode beam spot of the laser beam, and a three-dimensional stage (XYZ high-precision mobile platform) is used to move the laser to perform row and column dot scanning on the silicon surface. The laser forms plasma on the silicon surface, which resonates with the laser photons to form electron gas on the plasma surface. The photons resonate with the electron gas to form a two-dimensional electronic crystal structure, thereby realizing the preparation of a two-dimensional electronic crystal on the electron gas at room temperature.

[0005] The average power of the nanosecond pulse laser is 5-20W, and the repetition rate per second is 3-30K / s.

[0006] The diameter parameter of the laser beam fundamental mode spot is 30-80 microns.

[0007] The high vacuum is 10 -5 Pa.

[0008] The spacing of the row and column dot scanning is 0.1-1mm

[0009] The pulse width of the pulse laser is less than 100 nanoseconds, and nanosecond pulse laser, picosecond pulse laser or femtosecond pulse laser can be used, and the wavelength in the ultraviolet band is 355 nanometers.

[0010] The observation method of electron crystals uses a new reflective Talbot effect imaging method, in which Talbot laser is irradiated onto the above-mentioned silicon surface, and after reflection, photons are collected on a reflective Talbot effect imaging screen, thereby magnifying the 200-nanometer-scale electron crystal symmetry structure to the millimeter scale for naked eye observation.

[0011] The above method can realize the preparation of two-dimensional electron crystals on the surface of semiconductor silicon at room temperature; and the inventors also use the new reflection Talbot effect imaging method to capture the two-dimensional four-fold symmetric electron crystal structure and two-dimensional six-fold symmetric electron crystal structure on the silicon surface, etc., which can clearly observe the imaging of various symmetric structures of two-dimensional electron crystals, and use the reflection Talbot effect imaging method to capture the transient dynamic equilibrium image of the electron crystal on the silicon surface; through the electron crystal, the transient spectrum detects that its lifetime is about 100 nanoseconds. This lays the experimental research foundation for the high-end research on the preparation of electronic crystal structures at room temperature, and can also realize the regulation of the electron mobility of silicon surface materials to promote the research and development of silicon-based optoelectronic materials and devices. BRIEF DESCRIPTION OF THE DRAWINGS

[0012] Figure 1 The process and structure diagram of the method for preparing electronic crystals on the silicon surface using ultraviolet nanosecond pulsed laser. The symbols include: PLE laser pulsed laser etching, Talbot laser, Talbot lens, Talbot screen, Vacuum Chamber, Specimen Stage, Bar stage.

[0013] Figure 2 Reflection Talbot effect imaging of electron crystals with two-dimensional four-fold symmetry (a) and two-dimensional six-fold symmetry (b) on the electron gas on the silicon surface.

[0014] Figure 3 Measuring the transient spectrum gives the lifetime of the electron crystal on the silicon surface. DETAILED DESCRIPTION

[0015] Embodiment 1 of the present invention: A method for preparing an electronic crystal on a silicon surface using an ultraviolet nanosecond pulse laser, wherein an ultraviolet nanosecond pulse laser (average power: 5 W, repetition rate per second: 5 K / s) is used in a high vacuum (10 -5Pa) acts on semiconductor P-type silicon, uses a converging lens to adjust the diameter of the laser beam fundamental mode spot to about 50 microns, and uses a 3D stage to move the laser to perform row and column dot scanning on the silicon surface at 1 mm intervals. The laser forms plasma on the silicon surface, and resonates with the laser photons to form electron gas on the plasma surface. Under the action of the laser, the electron gas forms a surface two-dimensional electron crystal symmetry structure, and a two-dimensional electron crystal is prepared on the electron gas at room temperature; using the reflection Talbot effect imaging method, an astronomical telescope is used to invert the optical path to obtain parallel light to irradiate the silicon surface, and the plasma and optical path generated by the laser action are adjusted to capture the electronic crystal of the two-dimensional four-fold symmetry structure of the electron gas on the silicon surface, and then a reflection Talbot effect laser is used to irradiate the silicon surface and reflect and collect it on the reflection Talbot effect imaging screen, so that the electronic crystal of several hundred nanometers is magnified to the millimeter scale and can be clearly observed by the naked eye, such as Figure 2 (a) shown.

[0016] Embodiment 2 of the present invention: A method for preparing an electronic crystal on a silicon surface using an ultraviolet nanosecond pulse laser, wherein an ultraviolet nanosecond pulse laser (average power: 10W, repetition rate per second: 10K / s) is used in a high vacuum (10 -6 Pa) acts on semiconductor P-type silicon, uses a converging lens to adjust the diameter of the laser beam fundamental mode spot to about 50 microns, and uses a 3D stage to move the laser to perform row and column dot scanning on the silicon surface at 0.5 mm intervals. The laser forms plasma on the silicon surface, and resonates with the laser photons to form electron gas on the plasma surface. At room temperature, two-dimensional electron crystals are prepared by laser action on the electron gas; using the reflection Talbot effect imaging method, an astronomical telescope is used to invert the optical path to obtain parallel light to irradiate the silicon surface, and the plasma and optical path generated by the laser action are adjusted to capture the two-dimensional six-fold symmetric structure of the electron crystal on the silicon surface electron gas. Then, the reflection Talbot effect laser is used to irradiate the silicon surface, and the reflection is collected on the reflection Talbot effect imaging screen. The electron crystal of several hundred nanometers is magnified to the millimeter scale so that it can be clearly observed by the naked eye, such as Figure 2 (b) as shown.

Claims

1. A method for preparing electronic crystals on a silicon surface using ultraviolet nanosecond pulse laser, characterized in that: Nanosecond pulsed laser in the ultraviolet band is used to act on the semiconductor silicon surface in a high vacuum, and the fundamental mode beam spot of the laser beam is controlled by a converging lens. The laser is moved by a 3D stage to perform row and column dot scanning on the silicon surface. The laser forms plasma on the silicon surface, and the plasma and the laser photons resonate to form electron gas on the plasma surface. The photons resonate with the electron gas to form a two-dimensional electron crystal, thereby realizing the preparation of a two-dimensional electron crystal on the electron gas at room temperature.

2. The method for preparing an electronic crystal on a silicon surface using an ultraviolet nanosecond laser according to claim 1, characterized in that: The average power of the nanosecond pulse laser is 5-20W, and the repetition rate per second is 3-30K / s.

3. The method for preparing an electronic crystal on a silicon surface using an ultraviolet nanosecond laser according to claim 1, characterized in that: The diameter of the fundamental mode beam spot of the laser beam is 30-80 microns.

4. The method for preparing an electronic crystal on a silicon surface using an ultraviolet nanosecond laser according to claim 1, characterized in that: The high vacuum is 10 -5 Pa and above.

5. The method for preparing an electronic crystal on a silicon surface using an ultraviolet nanosecond laser according to claim 1, characterized in that: The row and column dot matrix scanning interval is 0.1-1mm.

6. The method for preparing an electronic crystal on a silicon surface using an ultraviolet nanosecond laser according to claim 1, characterized in that: The pulse width of the pulse laser is less than 100 nanoseconds, and nanosecond pulse laser, picosecond pulse laser or femtosecond pulse laser can be used, and the wavelength in the ultraviolet band is 355 nanometers.

7. A method for observing an electronic crystal as claimed in claim 1, characterized in that: Using the new reflective Talbot effect imaging method, the Talbot laser is irradiated onto the above-mentioned silicon surface, and after reflection, it is collected on the reflective Talbot effect imaging screen, thereby magnifying the 200-nanometer-scale electronic crystal symmetry structure to the millimeter scale for naked eye observation.

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