JPS58218113A - Light-emitting material - Google Patents

Abstract

PURPOSE:To make it possible to control a desired EOG (optional energy gap) and to change continuously the color of a light-emitting material by constituting a light-emitting material with amorphous silicon carbide that contains hydrogen and oxygen as the main body. CONSTITUTION:A light-emitting material consists of an amorphours silicon with composition of[(Si1-xCx)1-y-zHyOz]with 0<x<1.0<y<=0.5, 0<z<=0.07. After cleaning the surface of a substrate of a semiconductor of a single crystal silicon etc. a metal such as stainless steel, aluminium, etc., glass, ceramics, plastic, on which substrate a conductive film of a metal or metal oxide is provided, the substrate is placed in a glow discharge decomposition device. A mixture is made by mixing a suitable amount of hydrocarbon such as C2H2 that is gaseous at room temperature, and a compound containing silicon such as SiH4 and O2 that is gaseous at room temperature. Glow discharge decomposition is made in this mixture gas to disposite a-SiC that contains hydrogen and oxygen on the substrate.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a luminescent material made of silicon oxide (hereinafter abbreviated as a-SiC).

Conventionally, amorphous silicon containing hydrogen (produced by glow discharge decomposition method) has been used as a light-emitting material using an amorphous semiconductor.
For example, J. 1. Pankove, A”ppl.

Phys. Lett, 29. 620 (19
76), J, 1, Pankove.

Appl. Phys- Lett, 31. '45
0 (1977)) has been proposed. However, in the case of amorphous silicon, the emission intensity at room temperature is very weak due to thermal quenching. Furthermore, it is desired to realize a visible region light-emitting material that can emit light in the infrared range and therefore cannot be seen, but can be directly recognized.

Recently, in an attempt to solve these problems, a-SiQ, which has an optical energy gap (EOG) larger than that of amorphous silicon and is expected to be in the visible range, has been viewed as promising. Enggmann.

Appl, ph'yS, Lett. 32 (9)
567 (1978) iR. S.

Sussmann, Phi■. Mag, E. 44
．． 02H4 and SiH4 by 137 (1981)
Hydrogen-containing a-Si created by glow discharge decomposition of
It is disclosed that C exhibits visible luminescence. Also, a −
The existence and manufacturing method of SiO is explained by D. A.

Anderson and W.E. Pbi by Spear
]. Mag. ,■.

1 (1977), it is known that when the carbon concentration increases, EOG increases up to a certain concentration (after that, EOG decreases) (see Figure 1).

Note that this figure shows the data of Sussmann et al., and the horizontal axis is n (amount of silicon) in a S 1n O -1. ].

In the disclosure of light emission mentioned above, the EOG shows a similar trend to that reported by Anderson et al., with a maximum of about 2.8 eV and only a light emission color with a wavelength longer than orange or red.
A wide range of changes in luminescent color by changing the composition has not been reported, which limits its wide-ranging industrial application.

Furthermore, it is disclosed that a-8iC, which is obtained by glow discharge decomposition of monosilane and tetramethylsilane, which is a carbon-hydrogen-silicon compound instead of hydrocarbon, as a carbon source, emits a single white light. (H, Kuk
imoto, Appl, Phys,' I,e
tt-' 37. (6) 536 (1980)), but because this material uses tetramethylsilane as a carbon source, there is an upper limit to the carbon concentration (a-Sio, qco
, s is the highest - Kukimot.

(analysis)) It has a drawback in its wide selectivity as a luminescent material.

Furthermore, since tetramethylsilane, which is a raw material, is liquid at room temperature, it undergoes a vaporization process before being subjected to the reaction, which poses industrial problems from the standpoint of composition control and mass productivity.

The present invention investigated various amorphous materials, and used gaseous hydrocarbons and gaseous silicon-containing compounds. As a result of our earnest efforts to obtain an amorphous luminescent material with high industrial productivity, we have developed a new structure of a-5iC1 containing hydrogen and oxygen, that is, [(S1□-xCρ1-y-z
This invention was based on the discovery that an amorphous semiconductor with a composition represented by I (, o7.) is an excellent light-emitting material.

The present invention provides [(5il-XCx)1-y-zHyOz
] However, 19. Earth 0ku x 1,0ku y≦0.5.0<z≦0.07 and it's oh □ - my heart. I-I-I-I-I-K-E-I-I-K-E-I-I-K-E-I-K-E-I-K-E-K-E-K-E-K-E-K-K-K-K-K-K-K-K-K-K-K-K-K-K-K-E-K-E-K-E-K-E-K-E-K-E-with-with-K-!! 4□-・
□・. □Gao.

Furthermore, a composition range of 0.45≦x<1 is more useful. Furthermore, as for the amount of oxygen, a range of 0.01≦2≦0.07 is more useful.

Novel a-'Sin! containing hydrogen and oxygen of the present invention!
Because it is an amorphous material whose main constituent elements are Sl and C compared to a material whose main constituent element is Si (amorphous silicon), it is possible to realize a wider EOG, and
Continuously various values of E can be obtained by changing the composition ratio of i and C.
oa can be realized and is practically useful.

Therefore, by increasing the amount of X in Si-xCX, that is, the amount of carbon, it is possible to make it exhibit visible light emission, which also brings about advantages not found in conventional amorphous silicon (emissions in the infrared region) light-emitting materials.

The most characteristic feature of the amorphous light emitting material of the present invention is that it contains oxygen as a structural element. A-SiC, which contains oxygen and does not contain conventional oxygen: Extremely larger EO than H
G can be achieved. The change in Eioo also increases linearly with the carbon content within the composition range of the present invention, which is significantly different from the conventionally known results that have a peak with respect to the carbon content. silicon carbide (see Figure 2).

In addition, by including oxygen, the luminescence intensity is increased compared to the °C system that does not contain oxygen, which makes it more useful for practical purposes. This is presumably because oxygen effectively compensates for dangling bonds and reduces the probability of non-radiative transition.

On the other hand, when x=00, it becomes amorphous silicon, and when x-1, it becomes amorphous carbon, which is outside the scope of the present invention. That is, the scope of the present invention is amorphous silicon carbide whose BOG is controllable over a wide range and whose main constituent elements are Sl and C and which contains oxygen and hydrogen.

Furthermore, when X is in the range of 0.45≦x<1, light emission appears in the visible range, making it the easiest to put to practical use. Furthermore, by changing the composition X, the color of the emitted light can be arbitrarily selected such as red, orange, yellow, white, etc., and the emitted light intensity is high, so it has extremely great practical applicability. Furthermore, the present invention is the first to achieve white light emission in glow discharge decomposition of hydrocarbons and silicon-containing compounds.

Regarding the color tone of the emitted light, the half-width of the emitted light spectrum is wide, so it has the advantage of being soft (sniffing the eye).

On the other hand, when X is less than 0.45, light emission appears in the infrared region and cannot be seen directly with the naked eye, but compared to amorphous silicon, due to the presence of carbon, the light emitting ability at room temperature is superior.

When the oxygen amount y is less than 0.001 or more than 0.07, the effect of including oxygen as referred to in the present invention is small.

On the other hand, it is presumed that hydrogen contained in the amorphous material of the present invention acts particularly effectively to compensate for dangling bonds, which are the center of non-radiative transition of light emission.

If there is no hydrogen, many dangling bonds remain and the material is inferior as a luminescent material, but on the other hand, if there is too much hydrogen, the thermal stability decreases, which is not preferable when applied to devices.
,・In general, simply introducing carbon C into an Sl-based amorphous material that has a 4-coordinate diamond-type structure will result in a 4-coordinate structure, since carbon takes a 3-coordinate graphite structure when synthesized near normal pressure. It is not expected to obtain an amorphous material with a 5i-C network of 5. In contrast, in the present invention, by simultaneously introducing hydrogen and oxygen, an amorphous material with a high EOG [(s1□-xcX), -
,7H,o7:].

Compared to conventionally known systems, the amorphous material obtained by K in this way has a four-coordinated diamond-shaped structure that is more closely ordered ( long
-range-ordering), and it is presumed that this material has a high EOG. This also gives information on the amorphous band tail.
= -rw (hcEoo) The B value of the formula decreases by a certain amount when the amount of C is increased, but it can be inferred from the result that it increases again in the region where the amount of C is large when the amount of C is further increased (Fig. 3). reference).

The luminescent material of the present invention can be produced, for example, by the following method.

Chamber 6 is used as a substrate. If it can withstand a temperature range of 300°C to
The material may be appropriately selected from semiconductors such as stainless steel, metals such as aluminum, glass, ceramics, plastics, and materials whose surfaces are coated with conductive coatings such as metals or metal oxides.

After cleaning the surfaces of these substrates, they are placed in a glow discharge decomposition device as shown in Figure 4, and hydrocarbons that are gaseous at room temperature, such as C and H, and silicon-containing compounds that are gaseous at room temperature, For example, a-8iC containing hydrogen and oxygen can be deposited on a substrate by mixing appropriate amounts of SiH4 and 02 and performing glow discharge decomposition with this gas mixture.

The gas used for glow discharge decomposition may be diluted with HQ or a high-purity inert gas such as Ar.

In this case, the pressure of the mixed gas is maintained at about 0.05 to 5 Torr, but 0.2 to 2 Torr is more suitable.

The substrate temperature is preferably selected from room temperature to 300°C. The most practical temperature is room temperature to about 230°C.

Furthermore, when the substrate temperature is low, the luminescence intensity of the deposited film is high, and a luminescent material with excellent flexibility and moldability can be obtained using plastic as a substrate.

In particular, when adding impurities to change or improve electrical properties such as controlling valence electrons, gaseous compounds of group Ⅰ or group Ⅰ elements, such as BQH6 or PI (.

It is preferable to mix a diluent gas of AsH3 into the gas mixture for glow discharge decomposition.

Glow discharge is good at ℃, whether it is high frequency discharge or DC bias. As the discharge type, a capacitive coupling type is preferable.

Moreover, as a conductive film, Pt+Au+Al+In
404, 5nuQ, ITO, etc. can be used, but the more colorless and transparent the better.

The luminescent material of the present invention emits light in all visible light depending on the composition when stimulated by ultraviolet rays, electric rays, etc. In addition, a high dielectric thin film (YQ08 etc.) is used as a luminescent material according to the present invention.
tii, K $83. Eh, □yo, kake□: It can also be indicated by an area.

Since the luminescent material of the present invention is amorphous, it has the following features compared to those using conventional single crystals: (1) Any EO
G control allows for continuous changes in emitted light color (2) Easy manufacturing method, reaction at room temperature, and a wide range of substrate materials to choose from (3) Large surface area (4) Low cost audio It can be used as a level meter display, a digital display for home appliances, a signal display, an image display material, etc.

Next, the present invention will be explained in detail with reference to examples, but the present invention is not limited thereto.

Example 1 5iJ(4 and pure CQH4 diluted to 10% with hydrogen)
and O9 to change the mixing ratio as appropriate so that the C amount Each of the a-SiC containing hydrogen and oxygen shown at the sample points in Table 1 was deposited to a thickness of about 1 μm.

Table 1 shows the results of compositional analysis of the deposited film by Auger electron spectroscopy. In the measurement, Ar+sputtering was performed to completely remove the gas adsorbed on the film surface.

Table 1 The substrate on which the film was deposited was Oorning 7059 glass and single crystal S1, and the substrate temperature was maintained at 150°C.

The amount of hydrogen was determined from infrared absorption spectra and is shown in Table 1.

Also, from transmission and reflection spectroscopy measurements of films deposited on Corning 7059 glass, the JahvVBhν dependence was obtained using °C. , :Boo values are also shown in Table 1.

At the moment of reaction, J'I mixed crab. Pressure, yo. , 8 Torr
&, high frequency power is 13.56MHz, power is IOW
And so.

As seen in Table 1, the luminescent material of the present invention can control a wide range of EOG by controlling the composition (
(See Figure 2).

In addition, the EOo of a-8j:H obtained by observing the present device on a monthly basis was examined and found to be 17 to 1.83 eV.

Example 2 When the a-8jC containing hydrogen and oxygen obtained in Example 1 was irradiated with ultraviolet rays, samples Nos. 161 to 4 emitted light as shown in Table 2 under indoor light at room temperature. was confirmed.

Table 2 As shown in Table 2, the luminescent material of the present invention can exhibit luminescent colors across the entire visible spectrum by controlling the composition.

Regarding the luminescence intensity, the system with the luminescence peak at a short wavelength was found to be the strongest.

Note that sample A5 could not be seen with the naked eye because the emission was in the infrared region.

Example 3 The emission spectrum distributions of the samples in Table 1, Samples AI and 5 in Examples 1 and 2 were measured using a spectrophotometer and were as shown in FIG.

In the case of sample flat 1, the peak wavelength of light emission is approximately 530 nm.
1. Because the half width is wide at about 150 nm. It looks white to the naked eye. In addition, the peak wavelength of sample A5 is approximately 723
Luminescence was observed in the infrared region.

Example 4 The B values of the samples shown in Table 1 of Example 1 and the samples prepared by changing the flow rate ratio of SiH4/H9 and CQH4 in the mixed gas using the same method as in Example 1 were determined. On the other hand, it became as shown in Figure 3.

In general, the B value decreases as the carbon content (x) increases, and
・(However, it was found from Figure 3 that it peaked around x = 0.65 and then rose again.

Example 5 Example 1 is a typical example of the change in luminescence intensity due to the presence or absence of oxygen.
Sample A I and an amorphous compound containing no oxygen synthesized using only 8iH4 diluted to 10% with hydrogen and pure C2H4 as the reaction gas (5loo7co). , 5Q
The intensity determined from the emission spectrum of Ho, 41'' is shown as a representative example.

When the emission intensity of sample point 1 is set to 1, the oxygen concentration is
- The relative emission intensity ratio of the sample was approximately 0.05.

[Brief explanation of the drawing]

Figure 1 is a diagram showing the relationship between the composition of general amorphous SiC and EOG, Figure 2 is a diagram showing the relationship between the composition of amorphous SiC obtained by the present invention and EOG, and Figure 3 is a diagram showing the relationship between EOG and the composition of amorphous SiC obtained in the present invention. Amorphous S of the present invention
Figure 4 is a diagram showing the relationship between IC composition and B value, Figure 4 is a diagram explaining the manufacturing apparatus for the luminescent material of the present invention, and Figure 5 is a diagram showing the position and shape of the customer spectrum of the luminescent material of the present invention. be.
'・ 1... Reaction vessel, 2... Substrate holder/electrode, 3...
Gas outlet/electrode, 4...Gas inlet, 5...Gas exhaust port, 6...Substrate heating heater, 7...Thermocouple, 8
...Vacuum gauge, 9...High frequency oscillator. Applicant: Asahi Dow Co., Ltd. Agent Yutaka 1) Yoshio; 1゜Eng (Carbon content) 4 figures, 5 figures, length, continuation, amendments, July 1, 1980, Director General of the Patent Office, Waka Aiwao. 1. Indication of the case Patent Application No. 1982-940'09 2. Name of the invention Luminescent material 3. Person making the amendment Relationship to the case ・Patent applicant Asahi, 1-1-2 Yurakucho, Chiyoda-ku, Tokyo (046) Dow Corporation Representative Rei Yumikura -4, Agent Room 204, Sanshin Building, 1-4-1 Yurakucho, Chiyoda-ku, Tokyo Telephone: 501-2138□ 5. Explanation of "Issuing flEh7", #8 of the specification subject to amendment Column J and Drawings 6-1 Correct "For example, C2H2 and 1" on page 9, line 3 of the specification letter to "For example, C2H4 and 1." 6-2 Among the drawings, Figure 3 is corrected as shown in the attached drawing. In other words, the "B value (cm
-";6v-") J is [B value (cm-'eV-'
＞” I corrected it. z ・“・) ”] 1 Chang,,. 11

Claims (1)

[Claims] (J) [(S11-XCx)□-7-2H707] However, O<x<1, 0<ySO, 50<z<0.07
A luminescent material comprising amorphous silicon carbide having a composition represented by '. The luminescent material according to claim (1), characterized in that f21' x IJ''-0545≦x<1. A luminescent material according to claim (1).