JPH0738192A - Light emitting element - Google Patents

Abstract

PURPOSE:To obtain a high-output laser for ultraviolet ray and visible light by arranging a light emitting part including an active layer and a multi-chip field emission type electron source in the facing pattern, using the active layer as a dielectric wherein fluorescence substance is dispersed, and providing the light emitting part as an optical waveguide structure. CONSTITUTION:A field emission chip 2 is formed on a conductive Si substrate 1. An optical waveguide 9, which is constituted of a glass active layer 7, wherein ZnS:Ag is dispersed in the surface of a quartz plate, and a clad layer 8 of a quartz film coating the active layer 7, is formed in parallel with the substrate. A grating 10 is further formed on the surface of the waveguide. Then, an Al film is formed on the surface of the clad layer 8 by vacuum vapor deposition, Thereafter, the conductive substrate 1, on which the field emission chips 2 are formed, and the quartz plate 12, on the surface of which the optical waveguide 9 is formed, are bonded with solder in a vacuum with space 5 in-between. At this time, the field emission chips 2 and the optical waveguide are bonded so as to face each other. An Al2O3 film 14 is deposited on the emitting edge face. An Au film 13 is formed as an electrode at the rear surface of the quartz plate.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a light emitting device such as a laser used in the field of optical information processing such as optical recording, the field of optical applied measurement, and other fields of display.

[0002]

2. Description of the Related Art In recent years, in the field of optical information processing or the field of optical applied measurement, there has been a demand for a laser light source used to have a short wavelength, a small size and a light weight. Research and development of laser light sources are being carried out in various places.

As a conventional short-wavelength solid-state laser light source system, for example, as shown in Japanese Patent Application No. 1-8204, the active layer of a light-emitting element and a multi-chip field emission electron source are arranged to face each other. However, there has been proposed a light emitting device that excites and emits light in the active layer by an electron beam emitted by an electric field applied between the two. Figure 4 shows its typical structure.
Shown in.

FIG. 4 shows a method for exciting the active layer of the light emitting section by a field emission electron beam and a cross-sectional structure of a light emitting element in which the light emitting section and a multi-tip field emission electron source are arranged to face each other (special feature). Wishhei 1-8204 or USP 51193
86).

Here, 101 is a GaAs substrate, 102 is a ZnS clad layer, 103 is a ZnS active layer, and 104 is S.
io ₂ film, 105 SiO ₂ film, 106 field emission chip, 107 Si substrate, 108 vacuum space, 109 M
o electrode film.

As described above, as a conventional material for the active layer, II
A blue laser beam was obtained by using a group IV compound semiconductor and an active layer having a so-called slab type optical waveguide structure.

[0007]

However, as described above, when the II-VI group compound semiconductor is used as the material of the active layer, the expensive GaA of the III-V group is used for lattice matching.
An expensive device such as a MOVPE crystal growth device was required, using an s crystal substrate. Further, since the structure of the active layer is a slab type optical waveguide structure, in addition to the problem that single transverse mode oscillation is difficult, the refractive index of the II-VI group compound semiconductor is
Since it is smaller than the III-V group semiconductor, it is difficult to close the light, and the laser oscillation threshold value becomes high. Further, the oscillation wavelength is limited by the II-VI group semiconductor used, and various oscillation wavelengths cannot be obtained.

Therefore, an object of the present invention is to provide a laser having a single oscillation mode and a desired oscillation wavelength by forming an optical waveguide with a dielectric material in which a phosphor is dispersed.

[0009]

In order to solve the above-mentioned conventional problems, the present invention arranges a light emitting portion including an active layer and a multi-chip field emission electron source so as to face each other,
In a light emitting device that excites and emits light in an active layer by an electron beam emitted by an electric field applied between the two, the active layer is a dielectric substance in which a phosphor is dispersed, and the light emitting portion has an optical waveguide structure. And a light emitting device.

[0010]

The function of this technical means is as follows. That is, in a light emitting device in which a light emitting section and a multi-chip field emission electron source are arranged to face each other, and the active layer is excited and emits light by an electron beam emitted by an electric field applied between the two, the active layer is a phosphor. Is a dispersed dielectric,
In addition, when the light emitting portion has an optical waveguide structure, the phosphor in the optical waveguide emits light by electron beam irradiation, and the light propagates through the waveguide. The emission wavelength is determined by the matrix and activator that constitute the phosphor. For example, a phosphor having ZnS as a base material and Ag as an activator has a blue emission peak wavelength of about 450 nm, and a phosphor having Zn ₂ SiO ₂ as a base material and Mn as an activator has an emission peak wavelength of about 525 nm. Green and Y
_A phosphor having ₂ O ₃ as a matrix and Eu as an activator has a red emission peak wavelength of about 611 nm. Further, by installing a reflecting mirror inside or outside the optical waveguide and installing a resonator, laser oscillation occurs at the emission peak wavelength of each phosphor or the wavelength set by a wavelength selection element such as a grating.

[0011]

FIG. 1 shows the structure of a light emitting device according to the present invention, and FIG. 2 shows its sectional structure. A field emission chip (emitter) 2 is formed on a conductive substrate 1 made of metal or Si, and a gate electrode 4 is formed around an electron source via an insulating layer 3 made of SiO ₂ . The vacuum space 6 is formed between the optical waveguide 9 and the spacer 5 having a thickness of about 10 μm. The optical waveguide 9 is formed on the quartz substrate 12 by the glass layer 7 in which the blue phosphor ZnS: Ag is dispersed and the SiO ₂ layer 8 by the sputtering method, the glass layer serves as the core, and the quartz substrate and the SiO ₂ layer 8 serve as the clad. ing. A grating 10 is formed on the surface of the SiO ₂ layer 8 of the optical waveguide and is set so as to oscillate at a specific wavelength. The surface of the optical waveguide 9 is covered with a thin Al film 11 to form an anode. An electrode 13 made of Au or the like is formed on the back surface of the quartz substrate 12 and is electrically connected to the Al film 11. Al ₂ O ₃ or S on the side surface of the device
A passivation film 14 of iO ₂ or the like is formed and a vacuum is maintained. Then, an electric field of several hundreds of volts is applied between the emitter 2 and the gate electrode by the electric field applying device 15 so that electrons are emitted from the emitter 2, and the electric field applying device 16 similarly passes between the emitter 2 and the anode 11 through the electrode 13. An electric field of about several hundred volts is applied, and the anode 11 accelerates the electrons emitted from the emitter, and
The electrons passing through the anode are guided to the glass layer 7 in which the blue phosphor is dispersed. The light emitted by the phosphor propagates in the waveguide and is reflected by the grating 10 at the same time, so that laser oscillation occurs.

Next, a method of manufacturing this light emitting device will be briefly described. First, the field emission chip 2 is formed on the conductive Si substrate 1 by a method utilizing anisotropic etching of Si crystals, a method utilizing cone-shaped deposition of Mo on a glass substrate having a metal film attached thereto, and the like. Since the size of one electric field chip is usually several μm in diameter, the active layer 7 is formed with a constant in-plane density so that the active layer 7 can be uniformly irradiated and excited with an electron beam. In parallel with the formation of the field emission chip 2, Zn having a width of several μm and a height of several μm is formed on the surface of the quartz plate 12.
An optical waveguide 9 composed of an active layer 7 made of glass in which S: Ag is dispersed and a cladding layer 8 made of a quartz film covering the active layer is formed by a CVD method or the like. Further, the grating 10 is formed on the surface of the waveguide by the holographic exposure method or the like. Then, an Al film is vacuum-deposited on the surface of the clad layer 8 by several hundred to several thousand angstroms. Then, the conductive substrate 1 on which the field emission chip 2 is formed and the quartz plate 12 on the surface of which the optical waveguide 9 is formed are bonded with solder such as In in vacuum with the spacer 5 interposed therebetween. At this time, the field emission chip 2 and the optical waveguide are joined so as to face each other. Finally, an Al ₂ O ₃ film 14 is deposited on the emitting end surface by a sputtering method or the like, and Au is used as an electrode on the back surface of the quartz plate.
The film 13 is formed.

A blue laser beam can be obtained by applying a voltage of several V to several hundred V between the conductive substrate 1 of the light emitting device thus manufactured and the electrode 13 on the quartz plate. it can. Further, by applying a voltage between the conductive substrate 1 and the gate electrode 11, electrons can be emitted more efficiently.

The electric field strength at the tip of the tip becomes extremely large as the radius of curvature of the tip becomes smaller, and electrons are emitted into the vacuum by the effect of this electric field.
The emitted electrons run in the vacuum space 6 while being accelerated A
The electrons of the fluorescent material in the active layer 7 that have passed through the 1-layer 11 are excited from the ground state to the excited state electron level. When the excited electrons make a transition to the ground state, the wavelength is about 450.
Emitting energy as nm light. In addition, the optical waveguide 9
If a resonator is formed inside or outside of, a blue laser light can be obtained by stimulated emission. In this embodiment, the grating 10 forms a resonator.

Further, in this embodiment, a part of the optical waveguide 9 is covered with the Al film 11, but this is to prevent the charge (excitation electrons) from being charged up due to the optical waveguide being an insulator. is there. That is, the Al film 11 and the Au electrode 13
If they are connected to each other, the exciting electrons injected into the optical waveguide or the active layer will always escape to the ground through the Al film 11 and the Au electrode 13, and will not be accumulated in the optical waveguide 9 or the active layer 7. However, if this Al film 11 does not exist, electrons are accumulated in the optical waveguide 9 as the electron excitation continues,
The voltage difference between the optical waveguide and the field emission chip gradually decreases. As a result, the energy of the excited electrons is reduced, resulting in a decrease in light output.

Next, an embodiment of the light emitting device in the case where the light emitting portion including the active layer and the multi-chip field emission electron source are formed on the same substrate will be described.

FIG. 3 shows a schematic structure of the substrate of the light emitting device of the second embodiment according to the present invention. In this case, 31 is a silicon substrate, 32 is an insulating film such as SiO ₂ , 33 is a field emission chip of tungsten metal, and 34 is a blue phosphor ZnS: A.
An active layer 35 composed of a glass layer in which g is dispersed, and a cladding layer 35 made of SiO ₂ constitute an optical waveguide 36 as a core and a cladding, respectively. Reference numeral 37 is a grating formed on the surface of the optical waveguide, and 38 is an Al film covering a part of the optical waveguide. 39 is an electrode such as Au. Four
Reference numeral 0 is a spacer, 41 is a passivation film such as Al ₂ O ₃ or SiO ₂ , 42 is a quartz substrate, and 43 is a vacuum.

Next, a method of manufacturing this light emitting device will be briefly described. First, an active layer 34 made of glass having ZnS: Ag dispersed therein and having a width of several μm and a height of several μm on a Si substrate 31.
An optical waveguide 36 composed of a clad layer 35 made of a quartz film covering the active layer is formed by a CVD method or the like. Further, the grating 37 is formed on the surface of the waveguide by the holographic exposure method or the like. Next, an insulating film such as SiO ₂ is vapor-deposited, and then tungsten metal is vapor-deposited as a mask to form a field emission chip 33 having a sharp tip by a photolithography technique and an etching method.

Now, blue laser light can be obtained by applying a voltage of several V to several hundred V between the cathode 33 and the optical waveguide 36 of the light emitting device thus manufactured. The operating principle of this light emitting element is almost the same as that of the first embodiment.

In this embodiment, the glass waveguide in which ZnS: Ag is dispersed is used as the active layer of the optical waveguide.
By using a glass waveguide in which Zn ₂ SiO ₂ : Mn, Y ₂ O ₃ : Eu, etc. are dispersed, laser oscillation of green, red, etc. can be obtained. It is obvious that the oscillation wavelength can be freely selected depending on the type of phosphor and the setting wavelength of the wavelength selection element, and a laser having an ultraviolet wavelength is also possible.

[0021]

The light emitting device according to the present invention directly excites the active layer with an electron beam emitted from a multi-chip field emission electron source that does not generate heat without indirectly converting energy due to a non-linear effect or the like. Since it is a system, a large output can be easily obtained. Further, since the light emitting portion has a waveguide structure, light is effectively confined, and as a result, a light emitting element having a low threshold and low power can be realized. Further, this device is suitable for integration and has high value.

[Brief description of drawings]

FIG. 1 is a schematic perspective view of the structure of a light emitting device according to a first embodiment of the invention.

FIG. 2 is a schematic cross-sectional view of a light emitting device in a first embodiment of the invention.

FIG. 3 is a schematic perspective view showing the structure of a light emitting device according to a second embodiment of the invention.

FIG. 4 is a cross-sectional structure diagram of a conventional light emitting device in which a field emission type electron beam is used to excite a light emitting device active layer and the active layer and a multi-chip field emission electron source are arranged to face each other.

[Explanation of symbols]

 1 Conductive Substrate 2 Field Emission Chip (Electron Source) 3 Insulating Layer 4 Gate Electrode 5 Spacer 6 Vacuum Space 7 Active Layer 8 Clad Layer 9 Optical Waveguide 10 Grating 11 Al Film (Anode) 12 Quartz Substrate 13 Au Electrode 14 Passivation Film 15 Electric field application device 16 Electric field application device 31 Silicon substrate 32 Insulating film 33 Field emission chip (cathode) 34 Active layer 35 Clad layer 36 Optical waveguide 37 Grating 38 Al film 39 Au electrode 40 Spacer 41 Passivation film 42 Quartz substrate 43 Vacuum

Claims (8)

[Claims] 1. Light emission in which a light emitting portion including an active layer and a multi-chip field emission electron source are arranged to face each other, and the active layer is excited and emits light by an electron beam emitted by an electric field applied between the two. In the element, the light emitting element is characterized in that the active layer is a dielectric material in which a phosphor is dispersed, and the light emitting portion has an optical waveguide structure. 2. The light emitting device according to claim 1, wherein the active layer is a core of an optical waveguide. 3. The light emitting device according to claim 1, wherein at least a part of the surface of the optical waveguide is covered with a metal. 4. The light emitting device according to claim 1, wherein an end face for reflecting light generated in the active layer and carried by the active layer is formed at an end of the optical waveguide. 5. A light emitting device according to claim 1, wherein a mirror surface for reflecting light generated in the active layer and an element for selecting a wavelength are arranged outside at least one of the optical waveguides. 6. The light emitting device according to claim 1, wherein a diffraction grating that reflects the light generated in the active layer and carried by the active layer is formed in a part of the optical waveguide. 7. The light emitting device according to claim 1, wherein the light emitting portion including the active layer and the multi-chip field emission electron source are formed on the same substrate. 8. The light emitting device according to claim 1, wherein the light emitting portion and the multi-chip field emission electron source are formed on a silicon substrate.