JPH02234302A - Light emitting material - Google Patents

Abstract

(57) [Abstract] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

[Detailed description of the invention] [Industrial field of application] The present invention relates to an electric field. Electric wire, X-ray. Ultraviolet light. Or it relates to a light-emitting member that has the function of emitting light such as fluorescence or phosphorescence by absorbing excitation energy such as visible light or infrared light. ? Conventional Technology] Various types of light-emitting materials that emit fluorescence or phosphorescence have been known in the past. For example, Ga, which is a direct transition type semiconductor,
■Crystals of Group 1V compounds such as As and fnP, ZnS,
In crystals of Group II to II compounds such as ZnSe, the band gap is larger than the band gap of these materials. When irradiated with energetic light, it is absorbed and emits light with lower energy than the irradiated light, that is, the excitation light. Furthermore, even so-called indirect transition type materials, such as SiC, can emit light quite strongly if recombination centers are created within the band gap. In addition, in highly ionic crystals, fluorescence occurs due to impurities. For example, in KCI: Tl'', TI'' ions are excited by short wavelength excitation light, and the fluorescence spectrum peaks at 196 nm and 249 nm. Such light emission is caused not only by electromagnetic waves but also by electron beams. For example, in YK0■S, a phosphor used in cathode ray tubes, Eu'' is added as an activator impurity, and red light emission is caused by electron beam irradiation. Examples of this include blue fluorescence caused by Ag'' on ZnS, ZnFz
Many examples are known, such as orange fluorescence caused by the addition of Mn to. Also, for example, Applied Physi
Another well-known method is to attach an electrode to a light-emitting member and apply an electric field to cause it to emit light, as shown in CS Letters 13 210 (1968). For example, if microcrystalline grains such as Mn-doped ZnS or Cu and CI-doped ZnS are dispersed in a binder as a light-emitting member, and an alternating current electric field is applied to the light-emitting member,
Light emission by so-called electroluminescence (EL) can be seen. These are used for displays, etc. Furthermore, injection light emission using a p-n junction of a direct transition type semiconductor such as a III-V group compound is also a well-known technology at present. Furthermore, the semiconductor laser is an improved version of the so-called LED that has made it possible to generate laser oscillation. For example, S. M.
Physics of Semicondu by Sze
ctor Devices Chapter 12 (John Wil
ey & Sons. (1981) and other standard reference books, and there are many products on the market. By applying excitation energy in various ways like this,
Light-emitting materials that emit light such as ultraviolet light, visible light, or infrared light are well known. In general, these light emitting characteristics are determined by the presence or absence of photoluminescence. This can be checked by examining the intensity and the emission wavelength distribution. [Problem to be solved by the invention 1] However, on the other hand, there were many products whose luminescence intensity was weak or did not emit light to the extent that their luminescence characteristics could be put to practical use.
In addition, even if a material has a fairly high internal quantum efficiency for light emission, its high refractive index means that the critical angle at which the emitted light can exit is small, so it cannot escape from the inside and is unable to escape before exiting. In many cases, the light is attenuated due to repeated multiple reflections. Furthermore, since the wavelength of the emitted light is often easily absorbed, multiple internal reflections are disadvantageous in terms of the utilization of the emitted light, and have become a major problem. In order to solve these problems, it is necessary not only to improve the physical properties of light emitting materials, but also to
It is necessary to devise ways to efficiently extract the emitted light to the outside as described above, but the phenomena in each case are quite complex, and it is difficult to solve them comprehensively. Ta. An object of the present invention is to provide a novel light-emitting member in which the substantial light-emitting intensity of the above-mentioned materials with weak light-emission is increased or new light-emitting characteristics are added. [Means to solve the problem]. The present invention provides a light-emitting member that emits light by applying excitation energy, in which the light-emitting member is composed of C, Si and G.
It is characterized by containing fine particles whose main component is one or more elements selected from the group consisting of AH. and A}I
It is contained in the form of t, where ^ is the element, and the content ratio of AH5 and AH is 8H3 /^■2≦0,! This is a light-emitting member that satisfies the following. By using the light-emitting member of the present invention, it has become possible to further increase the luminescence intensity and to make materials that have not been practically recognized to emit light emit light. In particular, from the viewpoint of ease of handling, it is desirable to use a light-emitting member that is a fine particle film or a binder-dispersed film in which aggregates of fine particles are deposited in layers on a substrate. It is not limited to membranes or binder-dispersed membranes. The fine particles used in the present invention may have a size comparable to or smaller than the emission wavelength. In the case of visible light emission, it is approximately 1 μm or less, preferably 0.1 μm or less, and more preferably 500 or less. Although the shape of the above-mentioned fine particles is not particularly limited,
It is more effective when the particles are relatively close to spheres and do not contain too large particles. The lower limit of the size is unknown, but according to observation results using a transmission electron microscope (TEM) and a field emission scanning electron microscope, even ultrafine particles with an average particle size of several dozen particles are effective. In practice, in order to handle the fine particles of the present invention as described above, it is sufficient to place them on some kind of substrate and fix them. In this case, the individual fine particles do not necessarily have to be in contact with each other and may be isolated on the substrate, but in general, in order to increase the overall luminescence intensity, it is necessary to form aggregations of fine particles, such as aggregates or deposited films. etc. is preferable. In the present invention, it is not necessarily clear why the fine particles of the material and the content and form of hydrogen in the fine particles cause an increase in luminescence intensity. However, as the material becomes finer particles, the surface area increases significantly, which may cause the surface to become active or cause some changes in physical properties. In addition to this, it is also possible that the light extraction efficiency increased due to a decrease in reflectance due to the atomization of light particles when the light is emitted from the center of the light emitting member to the outside. Furthermore, when the light-emitting member is a particulate film laminated on a substrate, the light emitted from a deep part of the surface of the film is not scattered much because the size of the particulates is much smaller than the wavelength of the light. It is also possible that the luminescence intensity appears to increase in order to reach this point. In addition, it is thought that the fact that the fine particles contain 10% or more of hydrogen atoms contributes to reducing dangling bonds and widening the band gap, giving flexibility to the random network, just as in normal amorphous materials. It will be done. Furthermore, our study results have shown that this effect is not sufficient when the amount of hydrogen is less than 10% in terms of the number of elements. In addition, the bonding mode of most of the hydrogens contained is AH3 /AH
Although a≦0.1 is preferable, this relationship is empirical and the reason is not clear. In the fine particles according to the present invention, materials of group Ⅰ such as amorphous silicon are used as materials that surprisingly increase the luminescence intensity, but Ge, C, and mixed materials thereof are also effective. The raw material gas used in the light emitting member of the present invention is Si
In addition to H<, examples of silane derivatives used for Si film formation, such as Si. H. etc. can also be used. moreover,
Other group II gases, such as CH. , CH30H.
C2}Ill and other hydrocarbon gases, as well as G
It is also possible to use e-based gases. In addition, Si-based gas and C
There are two types of gases, such as St-based gas and Ge-based gas. 3
It is also possible to use a mixture of different gases. Also,
The present invention is not limited to the above materials. Various methods generally used for producing ultrafine particles can be used to form the microparticles used in the light-emitting member of the present invention. For example, Japanese Journal of
Applied Physics, [21, 70
2, (1963) and C
hemistry Letters. 267, (19
Examples include a thermophoretic CVD method as seen in 136), and a method of synthesis in a liquid. Such methods for producing ultrafine particles are now well known in the field of ultrafine particles, and are not limited to the individual production methods mentioned above.
For information on these various methods, see, for example, edited by the Chemical Society of Japan. Chemistry review No. It is introduced in detail in 48r Ultrafine Particles J (1985) and other publications. As an apparatus for manufacturing the light-emitting member of the present invention, for example, the apparatus shown in FIG. 1 can be used. In the figure, the nozzle 2 may be directly connected to the cavity resonator 5. The reaction gas is introduced into the cavity resonator 5 from the gas inlet lO.
When introduced into the chamber, the reaction takes place inside 5, and 5 acts as a reaction chamber. For example, when making a-Si fine particle film, Si}l4 gas and, if necessary, H gas are introduced from gas introduction 010, plasma is generated in the reaction chamber, the gas is decomposed and reacted, and the fine particles are Let it form. Then, this is ejected from the nozzle l along with some unreacted gaseous active species,
Spray onto the base 7 and fix. Microwaves, ultraviolet rays, or RF are used to give energy to gas.
Electromagnetic waves such as high-frequency waves, low-frequency waves, and electric fields such as direct current can be applied. In practice, ultraviolet rays or microwaves are the easiest to use, and although it is necessary to devise the shape of the reaction chamber, there is no need to place structures such as electrodes in the reaction chamber, and it is possible to use a window for energy input. Good. There are various ways to use microwave plasma, including Japanese Journal of Ap using a coaxial tube.
plied Physics 21 [8] L470
(1982), but from the standpoint of efficient particle formation, a method in which the reaction chamber is a microwave cavity resonator is very effective. Further, the nozzle 1 is provided to blow out the fine particles generated in the upstream chamber together with the remaining gas at high speed and onto the substrate 7 to fix them. Although the shape of the nozzle is not particularly limited, it is possible to increase the adhesion of fine particles to the substrate 7,
Furthermore, in order to form a beam of fine particles and collect them onto the substrate 7 at high speed and efficiently, it is desirable to use an ultrasonic nozzle that has a so-called contraction-expansion type aperture change from the upstream side to the downstream side. Its cross-sectional shape is not only circular but also
Modifications such as those shown in Japanese Patent No. 1-221377 can be used depending on the purpose. The temperature around the base chamber downstream of the nozzle is usually 10-3 Torr.
Use by lowering the pressure to the level below. It is desirable that the pressure ratio between the upstream and downstream sides of the nozzle ranges from several 10 to 100. The method of introducing hydrogen into the fine particles forming the light-emitting member of the present invention and the method of controlling the bonding mode of the contained hydrogen as described above will be explained below. ■As a means of generating plasma, for example, use microwaves! Gas is decomposed with high energy by inputting power of 00W or more. ■Use a gas with a high proportion of H2 or hydrogen as the carrier gas. ■Use hydrogen compounds as raw materials. Of course, a method of introducing hydrogen or a method of controlling the bonding mode other than the method described above may be used. In any case, it was found that the amount of hydrogen in the microparticles and its bonding style affect the luminescence intensity of the light-emitting member. Further, the particulate film in which the particulates are deposited on the substrate in the light-emitting member of the present invention may be provided with a protective layer on its surface. This protective layer is effective for increasing the mechanical strength of the particulate film and for preventing deterioration and other changes in the light emitting layer due to alteration. Bostyrene, polycarbonate and other organic polymers, inorganic glasses such as quartz and low-melting glass, or SiN,
A-C and other plasma polymerized films can be used. With organic polymers, it is convenient to use methods such as solvent coating.
It may also be used as a binder-dispersed film in which the fine particles of the present invention are dispersed in a binder such as a synthetic resin. In that case, the binder material may be coated on the surface of the fine particles using a heating evaporation method or the like and then deposited. [Examples] The present invention will be specifically described below based on Examples. Example 1 Using the apparatus shown in FIG. 1, a-St:H fine particles were deposited on a silicon substrate 7. To create the light emitting member, first set the silicon wafer substrate on the substrate holder 6, and then use the exhaust system 11 to open the downstream chamber 4 by 2
The pressure was reduced to 10-'Torr. Next, 1% with H2 gas
SiHa gas diluted to 10% was flowed into the cavity resonator 5 from the gas introduction pipe IO at a flow rate of 1503 CCM. Then, the pressure inside the cavity resonator 5 becomes 4 X 10'' Torr, and the gas containing Si}l< is blown out from the nozzle 1 to the downstream chamber 4. At this time, the pressure inside the downstream chamber 4 is 4.5 X In- 3To
It became rr. Next, microwaves were sent from a microwave oscillator (not shown) into the cavity resonator 5 through the waveguide 9 and the quartz window 8 to generate discharge plasma within the cavity resonator 5. The power of microwaves! It was 50W.
Then, fine particles are formed in the plasma, which are blown out from the nozzle 1 into the downstream chamber 4 along with the remaining gas components, and collide with the base body 7 in the downstream chamber 4 as a fine particle beam, thereby fixing the fine particles on the base body 7. The thickness of the layer of fine particles deposited on the substrate 7 was 3.0 μm after 6 minutes of discharge. The color of the fine particle deposits was brownish and shiny. Comparative Example 1-1 Example 1 except that the microwave power was changed to 60W
Fine particles were obtained in the same manner as above. The thickness of the layer of fine particles deposited on the substrate 7 was 5.3}Ill after 25 minutes of discharge. Further, the state and color of the deposition of fine particles were the same as in Example 1. Comparative Example 1-2 SiJ
A thin film of a-Si:H was obtained using s and 2 with the substrate water-cooled. The thickness of the film is 1.2μ, and it is a brown uniform film.
The bonds between Si and Si were mainly St-H bonds. Example 2 In the same manner as in Example 1, SiH. Gas to H, gas to 3
% and was flowed at a flow rate of 1003 CCM. Other conditions were the same as in Example 1 to obtain fine particles. The thickness of the deposited layer was 2.2μ after 6 minutes of discharge,
The state and color of fine particle deposition were the same as in Example 1. Comparative Example 2 H to be diluted, gas from Hi 100% to Hz/Ar=2
Fine particles were obtained in exactly the same manner as in Example 2, except that the mixed gas was changed to a mixed gas of: The thickness of the stone deposited with fine particles deposited on the substrate 6 was 2.5 μ- in 1 minute. In addition, Comparative Example 2 is similar to Example 2 in terms of the state and color of fine particle deposition.
There was no difference. Example 3 Using the apparatus shown in FIG. 1, a film was formed on a glass substrate by a method similar to Example 1. The raw material was CH4 gas diluted to 5% with ■2 gas, and the gas flow rate was 753 CCM. The pressure inside the cavity resonator at this time is! ．． 2 x 10-'
Torr, and the microwave power was 200W.
This film was also a brown, shiny, film-like deposit. The membrane prepared as described above was evaluated on the following two items. ■Photoluminescence (PL) At room temperature, each film was irradiated with blue light from an ion laser (λ = 488 nm), and the spectrum was observed using a spectrometer. ■Hydrogen content: Each film was subjected to FT -Analyzed by IR, a-Si:}!
The membrane has a peak at 2000-2300 cm-' a-C:
For the H film, the amount of hydrogen was calculated from the peak area of 2900 to 3000ca+-'. ■AH2/A}lm ratio■ From the FT-IR chart, the a-Si:H film is 21
00cm-' to SfH2 peak 2150cm-' to S
Considering the peak of il{s, the area ratio was determined by approximation to a Gaussian function and peak separation. In addition, the a-C:H film has 2925 cm-' of CH. The peak at 2960 cm-' was considered to be the peak of CL, and the area ratio was similarly determined by peak separation using a Gaussian approximation.
■Membrane shape The surface condition of the membrane was observed using FE-SEM (manufactured by Hitachi).
A summary of the results is shown in Table I. (Left below) In addition, Example 1 and Comparative Example 1 are examples of calculating AH2/AL.
-1.1-2. The second chart of each FT-III,
4th. Figure 6, and Figures 2 and 4 are AHs /^H
, which has been expanded and converted into absorbance in order to obtain the ratio of
It is shown in Fig. and Fig. 5. Furthermore, a typical emission spectrum of Example 1 is shown in Figure 7. [Effects of the Invention] As explained above, according to the present invention, it is possible to make a material that normally does not emit light emit light, or to dramatically increase the luminescence intensity of a material that normally emits light.

[Brief explanation of the drawing]

FIG. 1 is a diagram showing an example of the apparatus used to create the light-emitting member of the present invention, and FIGS. 2 to 6 are FT-
Figure 7 is a diagram showing an IR absorption spectrum, and Figure 7 is a diagram showing a fluorescence spectrum due to excitation light of an Ar ion laser. l...Reduction/enlargement nozzle 2...Nozzle throat 2a, 2b...Nozzle opening 3...Magnet 4...Downstream chamber 5. ...Cavity resonator 6 ...Base holder 7 ...Base 8 ...Microwave input window 9 ...Microwave waveguide IO ...Gas inlet 1l...Exhaust system patent applicant Canon Inc.

Claims (1)

[Claims] A light-emitting member that emits light upon application of excitation energy, wherein the light-emitting member contains as a main component one or more elements selected from the group consisting of C, Si, and Ge, and contains hydrogen. The hydrogen is contained in at least the form of AH_3 and AH_2, where A is the element and the content ratio of AH_3 and AH_2 is AH_3. A light emitting member characterized by satisfying the following: /AH_2≦0.1.