TWI233212B - Red light emitting device and method for preparing the same - Google Patents

Abstract

The present red light emitting device comprises a substrate with an upper surface and a bottom surface, a silicon dioxide film positioned on the upper surface, a plurality of silicon nanocrystals distributed in the silicon dioxide film, a first ohmic contact electrode positioned on the silicon dioxide film, and a second ohmic contact electrode positioned on the bottom surface. The present method for preparing the red light emitting device first forms a sub-stoichiometric silica (SiOx) film on a substrate, wherein the numerical ratio (x) of oxygen atoms to silicon atoms is smaller than 2. A thermal treating process is then performed in an oxygen atmosphere to transform the sub-stoichiometric silica film into a silicon dioxide film with a plurality of silicon nanocrystals distributed in the silicon dioxide film. The thickness of the silicon dioxide film is between 1 and 10000 nanometers, and the diameter of the silicon nanocrystal is between 3 and 8 nanometers.

Description

I233212 (1) Description of the invention: [Technical field to which the invention belongs] The present invention relates to a red light emitting element and a method for preparing the same, and more particularly to a red light emitting element having a silicon-containing light emitting film and a method for preparing the same. [Previous technology] Since 2000 AD, the technology development of visible light emitting diodes has mainly focused on improving the brightness and efficiency of light emission. Since Monsanto, Hewlett-Packard and other companies in the United States successively introduced gallium phosphorous arsenide / gallium arsenide (GaAsP / GaAs) red light-emitting monopolar products in 1968, it has a 36-year history. After the oil crisis in 1973, Japan, based on its emphasis on energy consumption, developed a gallium phosphide (GaP) red light emitting diode with low power consumption and long life, and began to enter the visible light emitting diode market. At this stage, the production of optoelectronic elements (especially light-emitting elements) is mainly based on epitaxial technology, and uses elements such as III-V or Π · νι with direct band-gap as raw materials. Since the invention of the transistor in 1947, silicon has always played a very important role in the integrated circuit industry. According to Moore's Law's prediction, the component size of integrated circuits will be reduced to half of its original size about every 18 months. The # 1 law is mainly based on the results of continuous innovation of new technologies and the development of potential applications, and silicon materials are an important cornerstone of this rapid progress. After years of development, the process technology of Shi Xi materials applied to integrated circuits can be said to be the most complete and the lowest cost. Therefore, if silicon materials can be further developed into light-emitting elements, light-emitting elements can be specifically integrated with large-scale integrated circuits. Circuit (VLSI). Shi Xi material (Group IV element) is an inefficient light source at room temperature.

H: \ HU \ HYG \ Nuclear Energy Institute \ 92835 \ 92835.DOC 1233212 The main reason is that it is an indirect band-gap material, its optical radiation recombination rate is very low, and its internal quantum The internal quantum efficiency is only about 1 (Γ6 to 1 0-7), so that it has been excluded from its role as a light source. Therefore, the application of silicon materials in the optoelectronic industry is currently limited to detection. Device, charge-coupled device (Charge Coupled Device, CCD) array image sensor and solar cells and other light-receiving components. In 1990, the British LTCanham discovered that in the argon fluoride acid solution, the porous formed by the anode electrolytic silicon material Porous Si (PSi) materials can generate high-efficiency visible light sources (Reference: 〇 & 111 ^ 1111 ^., 8091 ·?]!} ^ Lett., 57, 1046 (1990)). Important inventions have initiated research teams from all over the world to invest in the development of silicon light sources. Between 2000 and 2003, many academic research institutions and researchers in the world have invested in the development of silicon-based light-emitting diodes. Exhibition (Reference: Mykola Sopinskyy and Viktoriya Khomchenko, Current Opinion in Solid State and Material Science 7 (2003) pp.97-109.). However, although there is good progress in the research and development of silicon-based light-emitting diodes However, so far there have not been any commercial light-emitting diodes and other optoelectronic products. Because porous silicon materials have a sponge-like structure, they have some major shortcomings in the application of light-emitting elements. In terms of mechanical properties Porous stone materials are not suitable for integration into standard semiconductor processes because they are fragile. In addition, porous silicon materials exhibit a high degree of activity in chemical properties, and are prone to chemical reactions with oxygen atoms in the air, which degrades the photoelectric performance. Therefore, it is difficult to control the change of its photoelectric performance with time.

HAHU \ HYG \ Nuclear Energy Institute \ 92835 \ 92835.DOC 1233212 [Summary of the invention] The main purpose of the present invention is to provide a red light emitting element with a cut light emitting film and a preparation method thereof. To achieve the above object, the present invention discloses a Honglian M piece and a method for preparing the same. The red light emitting element includes a substrate having an upper surface and a lower surface, a stone dioxide film disposed on the upper surface, a plurality of stone crystals distributed in the stone oxide thin film, and A first ohmic contact electrode disposed on the stone dioxide film and a second ohmic contact electrode disposed on the lower surface. The substrate may be a ρ-type lithium substrate or an η-type lithium substrate: and the -ohmic contact electrode may be made of tin oxide. The thickness of the silicon dioxide film is between i and 1000 nm, and the size of the stone crystal is between 3 and 8 nm. Another embodiment of the red light emitting it includes an alloy thin film on the substrate, a 2-ox-cut thin medium disposed on a partial surface of the alloy thin film, and a plurality of distributed in the diox-cut thin film. Shi Xidiao rice crystal, a first pole arranged on the Shi Di Xi thin medium: and: r a second ohmic contact on a local surface of the alloy thin film: Au thin alloy is composed of silicon, nickel and gallium, The first ohmic contact is two-base Γ, and the method of preparing a sintered quartz substrate or trioxide :: red light-emitting element is firstly a base: ratio thin film, where the second equivalent ratio of the oxygen-cut film is The ratio of silicon atomic numbers is identified. 1 / cold pancreatic oxygen atomic mathematical process to drive c. After a 'hot place in the oxygen environment order to make a part of the stone equivalent of this time equivalent to oxygen cut thin fortune.

H. \ HU \ HYG \ Nuclear Energy Research Institute \ 92835 \ 9283.5 DOC 1233212 forms a number of Shixunai crystals. Next, another thermal treatment process is performed in a hydrogen environment, the treatment temperature is between 500 and 600 ° C, and the treatment time is between 1 and 120 minutes. The sub-equivalent-ratio silicon oxide film is formed on the substrate by an atmospheric pressure chemical vapor deposition process. The atmospheric pressure chemical vapor deposition process uses digas silicon dioxide and nitrous oxide, or silane and nitrous oxide as a reaction gas at a flow ratio between 10: 1 and 1:10. The temperature of the atmospheric pressure chemical vapor deposition process is between 700 and 100 ° C, and the deposition time is between 1 and 300 minutes. This atmospheric pressure chemical vapor deposition process uses hydrogen, nitrogen, or argon as the transport gas' to uniformly mix the reaction gases and send them into the reaction chamber. [Embodiment] The quantum confinement effect makes the energy gap interval of the material widen as the size becomes smaller, so nanometer-sized crystals have unique optoelectronic properties that are different from those of ordinary large-sized materials. Therefore, in addition to the use of conventional porous silicon materials, researchers have also attempted to prepare 5 by forming silicon crystalline nanocrystals (SiliCon nan〇Cr ^ stal in high-stability SiO2 thin glands). Evening light source. The method for preparing silicon nanocrystals is to first use chemical vapor deposition technology to form a sub-stoichiometric silica film with excess silicon atoms (Excess of silicon). The ratio of atomic number to silicon atomic number (X) is less than 2. Subsequently, at least one high-temperature annealing treatment (Annealing) is performed to drive two different metal phases (that is, silicon and silicon dioxide) to separate from each other to form an order ( 〇rder) structure of silicon nanocrystals and homogeneous structure (Amorphous) of silicon dioxide, of which the silicon dioxide film is used as silicon

H: \ HU \ HYG \ Nuclear Energy Research Institute \ 92835 \ 92835.DOC -10- 1233212 Nano matrix is used as the matrix of the body. Because the silicon dioxide material has a homogeneous structure, there is no strain between the silicon nanocrystals and the silicon dioxide (Strain-free). The size and density of silicon nanocrystals can be controlled by working parameters such as film deposition temperature and annealing temperature. Another method for preparing silicon nanocrystals is ion implantation. Ion implantation technology is a mature technology that has been developed for many years. It has been used in tenth of the large-scale semiconductor volume circuit manufacturing process. Ion implantation technology implants accelerated silicon ions directly into the silicon dioxide film to form excess silicon atoms in a local area within the silicon dioxide film. After that, an annealing process is performed to drive the excess silicon atoms to nucleate and crystallize to form silicon nanocrystals hosted in a silicon dioxide film (parent structure). Ion implantation technology can adjust the concentration and distribution of excess silicon atoms (PrOflle) required for implantation in a specific local area and depth range by adjusting the energy and dose of implanted ions. In addition, delta structural defects (structurai de cts) are also formed during the ion implantation process, and these structural defects can reduce the activation energy of atomic diffusion, making it necessary to perform metal phase separation. The temperature of the annealing treatment is also relatively lowered. However, compared with the chemical vapor deposition process, the time required to form the excess silicon atom concentration due to the ion implantation technology is too long to be suitable for the light-emitting film of the light-emitting device. Chemical Vapor Deposition (CVD), which is widely used in semiconductor manufacturing processes, can be divided according to the operating temperature range (from 〇OO to 〇〇t :) and the working pressure range (from atmospheric pressure to 7Pa, etc.). For atmospheric pressure chemical vapor deposition (APCVD), low pressure chemical vapor deposition (LpcVD) and plasma strength

H: \ HU \ HYG \ Nuclear Energy Institute \ 92835 \ 92835.DOC -11-1233212 chemical vapor deposition (PECVD) and other three. Compared with the ion implantation technology, the chemical vapor deposition method has the advantages of accurately controlling the composition and structure of the deposited film, uniform and fast deposition rate, high yield, and low production cost. The metallographic structure of the silicon-containing thin film formed by low-temperature deposition processes such as low-pressure chemical vapor deposition and plasma-enhanced chemical vapor deposition is relatively loose, and it has many structural defects and impurities that inhibit crystal growth. The present invention chooses to use a high-temperature atmospheric pressure chemical vapor deposition process to prepare a silicon-containing light-emitting film of a light-emitting diode. Because the silicon-containing light-emitting film prepared under high temperature environment has fewer structural defects and impurities, and the complex silicon-nitrogen-oxygen (si_N-〇) complex can form silicon nanocrystals with high density and high density distribution. In this way, the fluorescence spectrum of silicon nanocrystals has high definition, high brightness, and a narrow spectral half width. FIG. 1 is a schematic diagram of an atmospheric pressure chemical vapor deposition apparatus 100. As shown in FIG. I, the atmospheric pressure chemical vapor deposition device 100 includes a reaction chamber, a high-frequency oscillating power source 12 disposed outside the reaction chamber 10, a graphite block 14 disposed in the reaction chamber 10, a An intake manifold 16 and an exhaust manifold 18. The graphite block 14 is used to carry a substrate 22 for thin film deposition. Preferably, the graphite block 14 itself has been previously deposited with a thin film 15 composed of silicon carbide and silicon dioxide to prevent the graphite block 14 from being attacked by oxygen molecules. 2 to 4 illustrate a method for preparing the red light emitting diode of the present invention. In preparing the light-emitting diode 50 according to the present invention, a substrate 22 is first placed on a graphite block 14 in a reaction chamber ιo, and then the graphite block 14 is heated to a deposition temperature TD by a high-frequency oscillation power source 12. The substrate 22 may be a p-type Shixi substrate or a Bu type:

H: \ HU \ HYGVf | [能 所 \ 92835 \ 92835.DOC • 12-1233212 substrate, and has an upper surface 23A and a lower surface 23B. Thereafter, a certain number of moles or a volume ratio of the reaction gas 17 is uniformly mixed through the intake manifold 16 by the transport gas (optionally hydrogen, argon or nitrogen) 11 and then sent to the reaction chamber 10. The reaction gas 17 may be a mixed gas of silicon dihydrogen hydride (SiH2Cl2) and nitrous oxide (N20), and the flow ratio or volume ratio of the two is between 1:10 and 10: 1. In addition, the reaction gas 17 may be a mixed gas of silane (SiHd and NzO), and the flow ratio or volume ratio of the two is between 1: 10 and 10: 1. The reaction chamber 10 is maintained at a deposition temperature Td —Predetermined time tD to form a silicon oxide (SiOx) film 20 with a second equivalent of excess silicon atoms on the upper surface 23A of the substrate 22, whose ratio (x) of the number of oxygen atoms to the number of wonderful atoms is less than 2. Other reactions By-products 19, such as nitrogen (N2) and gasified argon (HC1), are continuously discharged through the exhaust manifold 18. After that, an oxygen-containing gas is input into the reaction chamber 10 to form an oxygen-containing environment, and The temperature of the reaction chamber 10 is increased to a processing temperature TP and maintained for a predetermined time tp to perform a heat treatment process. The oxygen-containing gas may be oxygen, ozone (〇3), or other thermal decomposition at the processing temperature Tp to generate oxygen The molecule of the atom. The environment where the δH reaction reaches 10 will drive the excess equivalent atomic oxide in the second equivalent ratio oxide film to 200 to undergo crystal growth and aging processes, so as to transform the second equivalent ratio silicon oxide film 20 to form One with silicon nano crystal 2 4 SiO 2 film 26. The thickness of the silicon dioxide film 26 is between 1 and 100,000 nanometers, and the size of the silicon nanocrystal 24 is between 3 and 8 nanometers. In an oxygen-containing environment, the fluorescent center of the silicon-nitrogen-oxygen (Si-N_〇) dangling bond between the silicon nanocrystal 24 and the silicon dioxide parent tissue, some of which are suspended by oxygen H: \ HU \ HYG \ Nuclear Energy Institute \ 92835 \ 92835.DOC -13- 1233212 Atoms are replaced to form a red fluorescent center. Then, hydrogen gas is introduced into the reaction chamber 10, and the temperature of the reaction chamber is raised to the wind passivation temperature TPH. And maintain a predetermined time tpH to perform the surface passivation process of the silicon nanocrystal 24 in a hydrogen environment. The heat treatment process and the surface passivation process convert the second equivalent silicon oxide film 20 into a silicon nanocrystal 24bis. A silicon oxide film 26. The silicon dioxide film 26 is used as a host structure for the boarding of the shixi nanocrystal 24. Referring to FIG. 4, a layer of indium tin oxide (IT0) ) Constitutes a transparent ohmic contact electrode 28, and forms a ohm on the lower surface 23B of the substrate 22. Contact electrode 30 to complete the light emitting diode vessel 50. If a positive voltage is applied to the transparent ohmic contact electrode 28 and a negative voltage is applied to the ohmic contact electrode 30, the light emitting diode 5 () will be excited by the current and emit red Light 40. Fig. 5 illustrates the operating temperature and time of the deposition process, heat treatment process and surface passivation process of the present invention. As shown in Fig. 5, the deposition temperature is between · ° c to iioo ° c, and the deposition time tD is introduced In the range of i to 300 minutes, the temperature TP of the heat treatment process is between 800 and 1300 ..., and the treatment time tP is in the range of 丨 to 1 minute. The temperature Tρ of the surface purification process is between 500 and 60 ° C., and the working time tpH is between 20 minutes and 20 minutes. FIG. 6 is a light-excitation fluorescence of the crystalline silicon dioxide film of the present invention. Qing— 雠 _ 'PL) spectrum. The photo-induced fluorescence spectrum is obtained by directly irradiating the hafnium dioxide film 26 'with an argon laser beam (wavelength of 488 nanometers), and then measuring the light-induced fluorescence emitted by the nano-crystal 24. As shown in Figure 6_, the light emitted from the nano-crystalline film 26 in the dioxy-cut film 26: Rong

H: \ HU \ HYG \ Nuclear Energy Institute \ 92835 \ 92835.DOC -14-1233212 2 The wavelength is between _ 纟 85G nanometer and the peak wavelength is between 650 and 750 nanometers, which is the red light of visible light . FIG. 7 illustrates a light emitting diode 70 according to a second embodiment of the present invention. As shown in the figure, the light-emitting diode 70 includes a substrate 33, an alloy thin film 60 disposed on the substrate 33, and a second surface of the alloy thin film 60, a fossil evening film 26,- The transparent electrode X on the thin film 胄% is placed on the ohmic contact electrode 64 on the local surface of the alloy film 60. The silicon dioxide film 26 is prepared by the method described above, so it has silicon that can emit red light. Nano crystal 24. The alloy thin film 60 is composed of silicon, nickel, and gallium, and is an n + type, that is, an n + -GaNiSi thin film. The ohmic contact electrode 64 may be made of titanium and aluminum alloy. The substrate 33 may be a quartz The magic substrate is an Al2O3, Sapphire substrate. The present invention uses a high-temperature atmospheric pressure chemical vapor deposition process to prepare the sub-equivalent ratio silicon oxide film 20, and the chemical reaction formula is:

SiH2Cl2 + xN20- > SiOx + xN2 + 2HC1 has a deposition temperature (TD) between 700 and 1100. (: In a high temperature environment, using hydrogen milk, nitrogen or argon as the transport gas, uniformly mix a predetermined number of moles or volume ratio of SiH2Cl2 and Νβ compounds and send them into the high temperature reaction chamber. In the high temperature reaction chamber 10, 8汨 2 €: Two gases, 12 and n2O, will be dissociated into atomic state at high temperature, and then recombined to form silicon oxide of subequivalence ratio and deposited on the substrate 22. The silicon oxide deposited on the substrate 22 contains excess stone Even the atomic component and excess silicon atomic component can be measured by the non-destructive detection method to determine the relative ratio of the number of oxygen atoms to the number of excess silicon atoms (0 / si). For example, by measuring its relative to standard dioxide The refractive index of silicon (Si〇2) \ 92835 \ 92835.DOC -15-1233212 can be used to infer the relative ratio of the number of oxygen atoms to the number of excess silicon atoms (O / Si). 0 The melting point (TM) of silicon is about It is 143 (TC, and its crystallization nucleation temperature (τN) is about 0 6 xT # 858 ° C. The deposition temperature (Td) of this second equivalent to the silicon oxide film 20 is between 700 ° C and 1 i0 (rc Has been significantly higher than the crystallization and nucleation temperature, so the silicon dioxide film at 20 During the deposition process, the high temperature in the reaction chamber 10 also drove the excess equivalent atoms in the second equivalent silicon oxide film 20 to form silicon nanocrystalline nuclei, and formed the silicon nanocrystalline nuclei and the parent ( The structure of the interface between silicon dioxide and silicon. The interface structure between the silicon nanocrystal and the matrix is mainly composed of hang-down bonds (&n; iangUngbonds) and nitrogen-oxygen bonds around the silicon nanocrystal. For example, Dream-nitrogen bonds (bonds), myo-oxygen bonds (Si.〇b〇nds), and Shi Xi_nitrogen-oxygen bonds (si Nx 〇y). The interface structure is the main fluorescent center (luminescenee eenten). In an oxygen-containing environment, annealing processes such as the growth and maturation of Shixi nanocrystals 24 are performed. The main structural composition of the second equivalent oxygen cut film 2G includes a homogeneous structure (Am〇1ph〇us) of oxidized stone and excess Polymers formed by Shixi Atoms (C1 steals most of the excess Shixi Atomic Groups, and most of the Shixi Nanocrystalline nuclei have been formed. This sub-equivalent ratio oxygen cut film 2Q is placed in the high temperature environment of heat treatment 'And hold for a period of time T j tp The growth of silicon nanocrystals 24 and the maturation of the interface structure, that is, P converts the δH-human-ratio silicon oxide film 20 into silicon oxide films 26 with silicon nanocrystals 24 μM. Oxygen atoms can interact with silicon Atoms have strong bonds, 埏 ... the interface structure of silicon-nitrogen-oxygen bonds (SbNx-Oy) is the main fluorescent light ^ shoulder is the ratio of rat to oxygen atoms (x / y) can get red Photofluorescence center. Preferably, the size of the y-free crystal 24 is controlled

H: \ HU \ HYG \ Nuclear Energy Institute \ 92835 \ 92835.DOC -16-1233212 is between 3 and 8 nanometers. In addition, if the excess silicon atoms in the second equivalent silicon oxide film do not form a silicon crystal core in the deposition process, the high temperature of the heat treatment process will further drive the excess equivalent silicon in the second silicon oxide film within 20 Atom nucleation. Then, 'the silicon dioxide film 26 having the silicon nanocrystal 24 is placed in a hydrogen environment' and maintained at a predetermined temperature TpH and time tPH to perform a hydrogen passivation treatment on the surface of the silicon nanocrystal 24 (Hy (jr〇gen passivati). After the surface purification treatment is completed, the silicon dioxide film 26 having silicon nanocrystals 24 forms a stable red light-emitting film. Compared with the conventional technology, the present invention uses a high-temperature atmospheric pressure chemical gas. Phase deposition technology and heat treatment technology to prepare a red light-emitting diode 50 with a silicon-containing light-emitting film (that is, a silicon dioxide film 26 with shixi nanocrystals 24) have the following advantages: 1 The invention does not require the use of complicated The epitaxial process and expensive process equipment only need to deposit a layer of equivalent ratio of silicon oxide film 26 and heat treatment process, which has the advantages of simple and fast process. 2. The present invention uses atmospheric pressure chemical vapor deposition process to prepare the equivalent Compared with the silicon oxide film 20, the atmospheric pressure chemical vapor phase process can be integrated into the standardized semiconductor process, so the present invention has the advantage of mass production of light emitting diodes. The know-how uses III-V compounds to prepare light-emitting films of light-emitting elements and thus is expensive to manufacture. The present invention uses silicon oxide to prepare silicon-containing light-emitting films of light-emitting diodes 50, so the materials and manufacturing costs are relatively low. HAHlAHYGVfli Energy Institute W2835 \ 92835.DOC -17-1233212 4. Group III-V compounds used in conventional technology can produce toxic chemicals. The present invention uses silicon oxide to prepare silicon-containing light-emitting films of light-emitting elements, and is free of chemical and toxic heavy metals. The problem of use and emission is a green process. 5. The present invention selects high temperature conditions to form a silicon oxide film 20 with a second equivalent ratio of excess silicon atoms, and then heat-treated to convert it into a silicon dioxide film with a silicon nanocrystal 24. 26, which has high temperature stability, and has a narrow and wide red light spectrum distribution. 6 · Since high temperature TP heat treatment, the equivalent of silicon dioxide film with higher density and higher density distribution than silicon dioxide film 26 The crystal 24 and the lower impurities', therefore, the Shixinan crystal 24 and its interface structure can be excited to produce a clearer and higher brightness spectrum. The technical content and technical features have been disclosed as above, but those familiar with the technology may still make various substitutions and modifications without departing from the spirit of the invention based on the teaching and disclosure of the invention. Therefore, the scope of protection of the invention should not be limited to the embodiments The disclosed should include various substitutions and modifications that do not depart from the present invention, and are covered by the following patent applications. [Brief Description of the Drawings] Figure 1 is a schematic diagram of an atmospheric chemical vapor deposition device; Figures 2 to Figure 4 illustrates the method for preparing the light-emitting diode of the present invention; Figure 5 illustrates the operating temperature and time of the deposition process, heat treatment process, and surface passivation process of the present invention; Figure 6 shows the silicon nanocrystals of the silicon dioxide film of the present invention. Photo-induced fluorescence spectrum; and

HAHU \ HYG \ Nuclear Energy Institute \ 92835 \ 92835.DOC -18-1233212 Fig. 7 illustrates a light emitting diode according to a second embodiment of the present invention. [Description of component symbols] 10 Reaction chamber 11 Gas transport 12 Local frequency vibration power supply 14 Graphite block 15 Thin film 16 Intake manifold 17 Reactive gas 18 Outlet manifold 19 Reaction byproducts 20 times equivalent ratio Oxide film 22 Substrate 23A Surface 23B Lower surface 24 Silicon nanocrystals 26 Dioxide shattered film 28 Transparent electrode 30 Ohm contact electrode 40 Red light 33 Substrate 50 Light emitting diode 60 Alloy film 64 Ohm contact electrode 70 Light emitting diode 100 Chemical vapor deposition device H : \ HU \ HYG \ Nuclear Energy Institute \ 92835 \ 92835.DOC -19-

Claims (1)

1233212 Scope of patent application ... L A red light emitting element including:-a substrate having an upper surface and a lower surface; a silicon dioxide film disposed on the upper surface; a plurality of silicon nanocrystals distributed on the substrate Among the silicon dioxide films, the size of the shixi nanocrystal is between 3 and 8 nanometers; a first ohmic contact electrode is disposed on the silicon dioxide film; and a second ohmic contact An electrode is provided on the lower surface. _ 2. If the red light-emitting element in the scope of application for item i, wherein the thickness of the two-gas-fossilized film is between 1 and nanometers. 3. The red light-emitting device according to item i of the application, wherein the substrate is a P-type silicon substrate or an n-type silicon substrate. 4. The red light emitting element according to item i of the patent application, wherein the first ohmic contact electrode is made of indium tin oxide. 5. A kind of red light emitting element, comprising: a substrate; an alloy thin film disposed on the substrate; a silicon dioxide film disposed on a partial surface of the alloy thin film; a plurality of silicon nanocrystals distributed on Among the silicon dioxide films, the size of the silicon nanocrystal is between 3 and 8 nanometers; a first ohmic contact electrode is disposed on the silicon dioxide film; and a second ohmic contact An electrode is disposed on a partial surface of the alloy thin film. 6. For example, the red light-emitting element in the scope of application for patent No. 5 wherein the stone dioxide H: \ HU \ HYG \ Nuclear Energy Institute \ 92835 \ 92835.DOC 1233212 The thickness of the thin film is between 1 and 10000 nanometers. . 7. The red light emitting device according to item 5 of the patent application, wherein the alloy thin film is composed of silicon, nickel and gallium. 8. The red light emitting element according to item 5 of the application, wherein the first ohmic contact electrode is made of indium tin oxide. 9. The red light emitting element according to item 5 of the application, wherein the substrate is a quartz substrate or a trioxide substrate. I 〇— A method for preparing a red light-emitting device, comprising the following steps: providing a substrate; forming a silicon oxide film having a first equivalent ratio on the substrate, wherein the oxygen atom number and the silicon atom number of the second equivalent silicon oxide film are formed on the substrate; The ratio is less than 2; and a first heat treatment process is performed in an oxygen-containing environment to convert the equivalent silicon oxide film into a silicon dioxide film with silicon nanocrystals, wherein the size of the silicon nanocrystals is between Between 3 and 8 nanometers. II. A method for preparing a red light emitting device according to item 10 of the patent application, wherein the silicon oxide thin film having the equivalent weight ratio is formed on the substrate by an atmospheric pressure chemical vapor deposition process, and the atmospheric pressure chemical vapor deposition process The temperature is between 700 and 1100 ° C. 12. The method for preparing a red light emitting device according to item 11 of the patent application, wherein the atmospheric pressure chemical vapor deposition process uses silicon dihydrogen hydride and nitrous oxide as reaction gases. 13. The method for preparing a red light emitting device according to item 12 of the application, wherein the flow ratio of the silicon dihydrogen hydride to the nitrous oxide is between 10: 1 and 1:10. 14. The method for preparing a red light-emitting device according to item 11 of the scope of patent application, in which H: \ HU \ HYG \ Nuclear Energy Institute \ 92835 \ 92835.DOC 1233212 ° Haihang chemical vapor deposition process uses silane and monoxide Dinitrogen is a reactive gas. 15. The method for preparing a red light emitting device according to item 14 of the Shenyan patent scope, wherein the flow ratio of " Hei Shixiu and the nitrous oxide is between 10 · · 1 to 1 · · 1 〇 between. 16. The method for preparing a red light-emitting device according to item 11 of the patent application, wherein the transport gas system in the atmospheric pressure chemical vapor deposition process is selected from the group consisting of hydrogen, nitrogen and argon. 17. The method for preparing a red light emitting device according to item 10 of the patent application, wherein the processing temperature of the first heat treatment process is between 800 and 1300 t :, and the processing time is between 1 and 1. To 300 minutes. 18. For example, the method for preparing a red light emitting device according to item 17 of the patent application scope further includes a second heat treatment process, the processing temperature is between 500 and 600, and the processing time is between minute. 19. The method for preparing a red light emitting device according to item 18 of the application, wherein the second heat treatment process is performed in a hydrogen environment. H: \ HU \ HYGVfe Energy Center \ 92835 \ 92835 DOC