Single Crystal Growth of Semiconductors from Metallic Solutions

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Another known method of producing single crystal material on a crystalline substrate, consisting in that it is placed in a reactor chamber, the chamber is filled with active gas, the laser beam from the gas phase to be crystallized is deposited on a substrate material and form a film thereon. Then, by using two laser beams to produce this film interference pattern of lines with a period equal to the period of the crystal lattice of the crystallizable material and produce its crystallization, forming a film on a substrate of monocrystalline structure see.

Russian patent W kl. Applying the known method for creating not only the security image on the sheet material of the single crystals of various materials is difficult due to the strict limitations imposed on the interrelation between the periods of the interference pattern and lattice crystallizable materials.

This way you can create a continuous film single-crystal structure, but it is impossible to ensure the growth of single crystals of the material only along the lines of the interference pattern, it is necessary to create an original image protection. Moreover, the implementation of this method requires the use of complex equipment, reactor chamber through which in a real print production almost impossible to pass the sheet material and to perform on it the operations described above, including forming on the sheet material through the chamber reactor interference patterns window.

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The basis of the invention is to provide such methods for producing on the sheet material of the diffraction grating of single crystals of metals, alloys and semiconductors and device for its implementation that would create a sheeting original is not reproduced in any other way the security image. The problem is solved in that, in the method of producing a sheeting grating of single crystals of metals, alloys and semiconductors is the fact that the sheet material is applied crystallizable materials salt solution was impregnated sheet material with this solution act on the specified sheet material point laser pulses and grown single crystals of these materials at the indicated points in accordance with the invention, a sheeting create an interference pattern from lines whose period is independent of the crystal lattices periods crystallizable materials grown single crystals of materials along these lines and of their totality form a diffraction grating.

With this method of producing a sheeting grating exclude the possibility of crystallization of materials outside of the interference lines and ensure the creation of a diffraction grating of single crystal material during the laser pulse duration, for interacting with interference lines salts solution crystallizable materials.

It is advantageous that the sheet material is set between an interference pattern of lines in the ranges 0,2mkm - O, 3mkm; 0,4mkm - 0. With such a method for producing a sheet material of the diffraction grating makes it possible to create on it a set of protective images. It is advisable that the form of lines of an interference pattern recess in the sheet material and the grown single crystals of materials in these recesses.

With such a method for producing a sheet material of the diffraction grating is provided its durability due to abrasion protection. The task is also solved by a device for obtaining a sheet material of the diffraction grating of single crystals of metals, alloys and semiconductors comprising means for applying to the sheet material salt solution crystallizable materials and means for extracting from the solution and crystallization of materials in accordance with the invention , means for extracting from the solution and crystallization of material configured as a generator of two laser beams, which cause an interaction between creation on a sheet ovom material an interference pattern of lines with a period that is independent of the crystal lattices periods crystallizable materials and the interaction of the rays with the sheet material along the lines of an interference pattern causes a growing single crystals of these lines materials from a solution of their salts.

With this arrangement, the device for the duration of the pulse interacting laser beams is provided to create placed in the natural environment sheeting grating of single crystals of metals, alloys and semiconductors, which creates a sheeting new, not reproducible by any other device security image.

Сведения о продавце

The invention is further explained by description of particular, but not limiting the present invention embodiments and the accompanying drawings, in which:. The proposed method of producing a sheeting grating of single crystals of metals, alloys and semiconductors is performed as follows. On the sheet material A FIG in the applied solution comprising the salt of one or more metals or semiconductors salt.

Was impregnated with the solution A and the sheet material fed to it the laser beams D and E, cooperating with each other so that a sheeting kaptina. This picture includes, for example, from parallel lines with a period that are not in the relationship of any particular period of crystal lattice with materials in solution and subject to crystallization.

Pulsed effect on the sheet material interacting laser beams D and E occurs along lines F of the interference pattern. During the pulse duration time lines of an interference pattern of laser radiation interacts with a solution, which is impregnated sheet material.

As a consequence the described process along the lines of an interference pattern formed by diffraction grating F G from single crystals of metals, alloys and semiconductors. With sufficient laser pulse power described process will be combined with the process of burning of the surface layer of the sheet material along the lines of an interference pattern, resulting in growing single crystals of metals, alloys and semiconductors occur in recesses formed along these lines.

The crystallization solution was introduced into the material will not take place outside the lines of an interference pattern due to the small laser pulse duration about 10 ns since with such a short pulse of heat possible spread beyond these lines. The proposed device for obtaining a sheet material of the diffraction grating of single crystals of metals, alloys and semiconductors comprises a means 1 for application to the sheet material 2 crystallizable materials and means 3 salt solution to separate out of solution and the crystallization of these materials. The means 1 for application to the sheet material 2 crystallizable materials salt solution comprises a reservoir 4 with the solution and a fixture 5 for impregnating the sheet material with this solution 2 comprising a number of drivers Fig.

Not shown of the rollers 6 for transferring the solution from the reservoir onto the sheet material. In this period of the interference pattern of lines is not in a certain relationship with the period of the crystal lattices of the material in solution and subject to crystallization. The sheet material 2 moves on technological positions its handling conveyor The proposed device for obtaining a sheet material of the diffraction grating of single crystals of metals, alloys and semiconductors is as follows. When the sheet material 2 on the conveyor 12, the rollers 6 on it is applied a solution containing a salt of one or more metals or semiconductors salt.

Then, the sheet material 2 is moved to the position of forming the diffraction grating thereon. Najetoy position as a result of the interaction between a pulsed laser beams 8 and 9 of the generator 7, directed through optical system 10 onto the sheet material 2 at a predetermined portion thereof an interference pattern 11 on the lines which the laser beam interacts with a solution of this material is impregnated.

As a result of this interaction during the laser pulse duration about 10 ns the lines of the interference pattern 11 is restored introduced into the material solution to a pure material as a result of its crystallization on a liquid substrate, a plurality grown along these lines of single crystals constitutes a sheeting diffraction grating Specifically speaking, a slightly tilted substrate is first covered with a thin layer of BPEA solution, and then a high-temperature annealing treatment is applied to make the solvent rapidly volatilize along the direction of the slope.

As a consequence, highly ordered single crystal arrays of BPEA are achieved very fast, generally within 10 s. This process can be controlled by the slope degree of the substrate as well as other affecting factors such as annealing temperature and solution concentration.

Single Crystal Growth of Semiconductors from Metallic Solutions by Sadik Dost | eBay

Compared with other technologies 50 , 51 , 52 , it is obvious that our method is time-efficient a couple of seconds , and easy to operate without any special instruments or complicated experimental procedures. Meanwhile, the BPEA arrays exhibit good electrical properties with the average mobility of 0. Figure 1 shows the schematic drawing of the experimental procedure to obtain the single crystal arrays via RASSS method. The substrate was placed on the heater which was kept at a high temperature and tilted at a tiny angle about 0.

The solvent was evaporated quickly from the whole liquid surface, leading to rapidly decreasing the liquid level. At the same time, dense seed crystals were generated at the contact line forming a seed-crystal band. After that, the self-solution-shearing effect guided the growth direction of the single crystal ribbons.

Simultaneously, evenly spaced seed crystals grew up following the solution receding along the specific direction Fig. As a consequence, large-scale and well-aligned ribbon crystals of BPEA were gradually obtained as shown in Fig. The self-solution-shearing process does not require any complicated technique or expensive equipment, and the whole process can be finished within ten seconds. Current-voltage characteristics of the devices were measured in the atmospheric condition using a Keithley SCS semiconductor parameter analyzer.

The morphologies and crystalline structures were characterized by optical microscope, atomic force microscope, transmission electron microscope, and X-ray diffraction technique, respectively. Then, the setup is kept at a desired temperature for rapid evaporation of the solvent. Using this RASSS method, large-area single crystal arrays with the length at the millimeter scale can be easily obtained, as shown in optical microscope image Fig.

From the optical images, it is clear that BPEA on these three substrates is well-aligned with a preferential growth direction along the solution shearing direction. Every individual ribbon had a regular configuration and a uniform color, which indicates that superior quality single crystal is achieved. From the X-ray diffraction patterns shown in Fig.

So it is concluded that the BPEA ribbons on different substrates are single crystals. This is also a valuable evidence that the growth of these single crystal arrays has no strong correlation with the used substrate. S1a and various concentrations 0. S1b were characterized by the X-ray diffraction. The surface morphology of individual single crystal ribbon was measured by AFM height mode mapping. Figure 3c demonstrated a faceted shape with a very smooth surface of averaged roughness about 0.

These images suggest that the formation of single crystal ribbons is independent of the substrate. The first one was the angle of the substrate slope, which decided the shearing direction and influenced the shearing speed. The effects of three different angles were tested with other identical experimental conditions temperature, concentration, location.

S2a and became discontinuous spots while the angle was too big about 1. Only around the middle state about 0. The temperature of the heater was another important factor, which had a close relationship with the evaporating rate of the solvent and the shearing speed. S2d could not result in the formation of the single crystal ribbon arrays. The last critical factor is the initial concentration of the solution.

S3b,d at the same heating temperature. It is noted that when the temperature increased in an allowable scope at the same concentration, the thickness varied within a certain range. This could be explained that higher temperature made the molecule in the solution have higher kinetic energy and when the solution sheared rapidly, more molecules would be transported to construct the single crystals arrays.

It was noted that selecting the appropriate solvent was also very important. Unfortunately, although the methylbenzene solvent could help to form single-crystal arrays as shown in Fig.

S4a , the morphology and the quality was not good as that from mesitylene solution and the performance was relatively low with the mobility of only 2. As for high boiling point solvent 1, 2-dichlorobenzene , there was no single crystal obtained Fig. However, at the same concentration but different temperature, the temperature had a slight impact on the density, which indicated that the concentration played an important role to determine the density. All of these could be explained as followed. At the beginning of the growth, a large number of crystal grains were generated at the contact line, but only a few could grow up with the solution shearing rapidly due to the limited resource.

However, with the concentration increasing, more crystal grains obtained the chance to grow up for a higher density. So we could control not only the orientation but also the thickness and density of the arrays through our RASSS process. When a drop of solution spreads over the substrate that had a very small slope, it will reach an equilibrium state quickly with the help of the interfacial tension among the substrate, liquid and gas phase Fig.

Herein, we think that the effect of gravity can be ignored because of the small slope and microliter scale solution. And the interfacial tension at the interface must satisfy the Young equation which is an basic equation in interfacial science According to the phenomenon of the experiment, we explain the mechanism depending on the Young equation though this picture. Figure a, b, c show a complete variation at the contact line between the solution and substrate where the interfacial tensions are regarded as the driving force. When the substrate was placed on the heater Fig.

The right side of the equation becomes greater than the left side. According to the mechanics principle, the contact line for pure solvent will shear along the direction of the slope to maintain mechanical equilibrium. However, in our experiment, the contact line would be pinned there owing to large amounts of crystal nucleus that generated at the contact line with the evaporating of the solvent. This pinning effect would prevent the interface from receding momentarily.

With the solvent evaporation, the local concentration increases and then reaches the saturation state. When the concentration is above the saturation, nucleation occurs to form the contact line. It is noted that higher temperature makes the molecules in solution own higher kinetic energy. This thermal motion brings the molecules to the contact line for the growth of single crystals arrays.

The preferential growth direction must have the highest binding force and closely arrangement of molecules. And the very high receding speed produces a constraining force to guarantee the yield of highly ordered single crystals along the preferential direction.

Single Crystal Growth of Semiconductors from Metallic Solutions

Finally, the system would recover to the initial state and repeat again as illuminated in Fig. Considering these crystals not fully covering the channel, the active channel width and length were measured from the contacting area of the crystals which crossed the drain and source electrodes. The distribution of the mobility based on 18 devices was shown in Fig. OFETs exhibit superior performance with the average mobility extracting from the saturation region of 0.

The typical transfer characteristic of the device was shown in Fig. The output characteristic was shown in Fig. The device also showed the expected gate modulation of the drain current I D in both the linear and saturation regimes. The single crystal arrays on the PI substrate also shared the similar electrical properties Fig.

Furthermore, we fabricated an inverter which was the basic gate circuit for large scale integrated circuits on the PI substrate with patterned electrodes by in-situ growth inset of Fig. The typical transfer and output characteristics of these devices were shown in Fig. Both of these arrays showed satisfying performance, which indicated our method had good universality in preparing organic single-crystal arrays. The active channel width was measured from the contacting area of the crystals which crosses the drain and source electrodes.

Czochralski Silicon Crystal Growth in the Vertical Magnetic Field

In conclusion, we develop a new method called RASSS which takes advantage of a tiny slope and rapid annealing to fabricate desired-orientation, highly-ordered single crystal arrays of organic semiconductor BPEA. Compared with other reported methods, our process is the simplest without any complicated procedures , the fastest only takes a few seconds and independent of the substrate. The average mobility is 0. It is believed that this method provides a new direction to fabricate single crystal arrays and the potential for the practical applications of large area organic electronics.

The polyimide substrates were prepared as follows: The gold source and drain were deposited by manually gluing Au-films. The channel length and width were measured by optical microscope. The inverter was achieved on the PI substrate, where the source and drain electrodes were patterned by photolithography.

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