JPS6321891A - Semiconductor light-emitting device - Google Patents

Abstract

PURPOSE:To stably emit far infrared light by applying an electric field to a direction in a surface or perpendicularly to the surface, applying the electric field perpendicularly to a quantum well having a plurality of quantum levels in a conduction band, a light emitting layer and the surface to form adjacently a quantum well having a different quantum level from the light emitting layer and as current implanted layer. CONSTITUTION:An AlAs layer 3 and a GaAs layer 4 for quantum wells have a common potential barrier which is thick enough to bring about tonneling of electrons between the two wells. Accordingly, when a bias voltage is so applied that the ground quantum level 6 of the layer 2 and the first exciting quantum level 8 of the layer 4 coincide at energy levels, the electrons at the level 6 occupy the first exciting quantum level 8 of the layer 4. The electron emits stable far infrared light having energy equal to the energy difference between the two quantum levels at transition to an unoccupied ground quantum level 7.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to a semiconductor light emitting device, and more specifically,
The present invention relates to a semiconductor light-emitting device that can stably and continuously emit far-infrared light.

[Conventional technology]

This type of conventional semiconductor light emitting device is described in Applied Physics Letters.
d Physics Letters) vol, 39
(3), FIG. 4 shows an energy band diagram of the quantum well semiconductor laser device shown in 1.198f.

That is, in the energy band diagram of FIG. 4, 7 is the base quantum level of the electron in the quantum well, and 1
8 is the base quantum level order of the same hole, 13 is the n-type A structure 0.48Ga0.52'' layer, 14 is the AM O,
f7Ga0.83As layer, 15 is p-type 71! LO, 48
It is a GaO, 52As layer.

Therefore, in this case, AM 0.17GaO, 8aA
S layer 14 and An 0.48”0.52” layers 13, 15
AIL a, 1
A quantum level of 7.18 is formed in the conduction band and valence band of the 7GaO, 83'' layer 14, and A lo , 4
By applying a forward bias to the pnPa layer 11.15 of the 8GaO, 52As layer, Auo, t7Gao, a3
When electrons and holes are injected into the A3 layer 14, the injected electrons and holes form a quantum well Ai0.17"0.83"
occupying quantum ground levels 7 and 18 of layer 14, respectively;
Laser oscillation is produced by the recombination of these electrons and holes and the emission of light.

[Problem that the invention seeks to solve]

In the conventional quantum well type semiconductor laser device, since it is configured in this way, A which becomes the quantum well layer
There is a problem in that only a laser beam having an energy higher than the bandgap of the aaAj layer 14, 4r-/p, can be obtained.

This invention was made to solve these conventional problems, and its purpose is to provide a semiconductor light-emitting device that can stably emit far-infrared light using a quantum well structure. The goal is to provide the following.

[Means for solving problems]

In order to achieve the above object, a semiconductor light emitting device according to the present invention includes a quantum well nine light emitting layer capable of applying an electric field in the in-plane direction and in a direction perpendicular to the plane and having a plurality of quantum levels in the conduction band; An electric field can be applied in a direction perpendicular to the surface, and a quantum well and a current injection layer, each having a quantum level different from that of the light emitting layer, are arranged adjacent to each other.

[For production]

Therefore, in the case of the device of this invention, by applying a vertical electric field to the quantum well as the light emitting layer, the quantum levels of electrons and holes are spatially separated, and recombination between electrons and holes is prevented. By applying an appropriate electric field in the vertical direction to the quantum well that serves as the current injection layer, electrons are injected into the excited quantum level of the conduction band of the light emitting layer by resonant tunneling, and far-infrared light is emitted. This allows stable luminescence.

〔Example〕

Hereinafter, one embodiment of a semiconductor light emitting device according to the present invention will be described in detail with reference to FIGS. 1 to 3.

1 and 2 show energy band diagrams of the device of this embodiment, and FIG. 3 is a structural explanatory diagram schematically showing the outline of the semiconductor light emitting device.

First, in the energy band diagram shown in FIG. 1 and the device configuration shown in FIG. are AILAs
layer, 4 is a non-doped GaAs layer as a light emitting layer, 5 is n
8 is the base quantum level formed in the quantum well of the A 31 ICat-, As layer 2 sandwiched between the A1As layers 1 and 3, and 7 is the LM As layer 3.
．． The base quantum level formed in the quantum well of the GaAs layer 4 sandwiched between 5 and 5, 8 indicates its first excited quantum level, and 9. IO is the bias power supply, lla and llb are the G
A pair of electrodes 12 formed in the in-plane direction of the aAs layer 4 are these substrates.

However, in the case of this embodiment configuration, since the AiAa layer 1 is n-type, the A statement! The base quantum level 6 of the Ga1-, As layer 2 is occupied by electrons, and the energy gap between the A-structure, Ga1-, As layer 2, which forms a quantum well, and the GaAs layer 4 is different. The energy level of the ground level in the quantum well formed in the conduction band of is also different. Therefore, in the state of 0 bias, the ground level
The electrons occupying the GaAs layer 4 are not tunneled into the conduction band of the GaAs layer 4.

In addition, A sentence x G a 1-x which becomes a quantum well here
A! serves as a common potential barrier between the As layer 2 and the GaAs layer 4! The LAs layer 3 has a thickness sufficient to cause electron tunneling between both quantum wells, as will be described later.

Therefore 1. In the case of this embodiment configuration, as shown in FIG.
AfL, base quantum level 6 of Ga1-8As layer 2 and Ga
When a bias voltage is applied to the As layer so that its energy level matches that of the first excited quantum level 8, the electrons occupying the base quantum level 8 move to the GaAs layer 4 by resonance tunneling. , and when this electron transitions to the ground quantum level 7 that is not occupied by an electron, it imparts an energy equal to the energy difference between the two quantum levels. This results in the emission of far-infrared light.

The following mechanism ensures that such a light emission phenomenon occurs only between the quantum levels of the conduction bands of both quantum wells.

That is, due to the electric field applied perpendicularly to the GaAs layer 4, the electron distribution in the conduction band is attracted to the side of the AlAs layer 3, as shown in FIG. 2, and the hole distribution in the -direction 9 valence band is is in the opposite direction to the electrons, that is, n-type AlAs
Since the electron distribution and the hole distribution are spatially separated in this way, recombination between electrons and holes does not occur, and the excited quantum level 8 The electrons accumulated in the ground quantum level 7 due to the transition from 2 to 3 are removed to the outside by a pair of electrodes 11a and 11b formed in the in-plane direction of the GaAs layer 4 shown in FIG.

In this way, the An, Gat□As, layer 2, which becomes the current injection layer,
Electrons are stably supplied by resonance tunneling from the fundamental quantum level 8 of the GaAs layer 4 to the first excited quantum level 8 of the GaAs layer 4, which becomes the light emitting layer, and a stable far-infrared light is generated between the quantum levels 7 and 8. This causes continuous emission of external light.

Note that in the configuration of the above embodiment, the current injection and the
i! Although the light-emitting layer and the light-emitting layer are formed of GaAs, GaAs may also be formed. Since the quantum levels are different, the same actions and effects as in the same embodiment can be achieved.

Further, in the above embodiment, Gaps and AfLAs epitaxially grown thereon have been described, but any material may be used as long as it has a similar quantum well structure, and furthermore, the structure of the above embodiment may be used.

By separating the opposing end faces of the device to form a Fabry-Perot type resonator, it can be used as a far-infrared laser oscillator.

〔Effect of the invention〕

As detailed above, according to the present invention, an electric field can be applied in the in-plane direction and in a direction perpendicular to the plane, and a quantum well as two light-emitting layers having a plurality of quantum levels in the conduction band and a quantum well in the plane A quantum well serving as a current injection layer, which can apply an electric field in the vertical direction and has a quantum level different from that of the light emitting layer, is placed adjacent to the quantum well.
By applying an electric field in the vertical direction to the quantum well, resonant tunneling is caused between the two quantum wells, and the electron distribution and hole distribution in the light emitting layer are spatially separated.
Recombination between electrons and holes can be prevented, and as a result,
It has the excellent feature of being able to emit far-infrared light stably and continuously using a quantum well structure.

[Brief explanation of the drawing]

1 and 2 are energy band diagrams of one embodiment of the semiconductor light emitting device according to the present invention, FIG. 3 is a configuration explanatory diagram schematically showing the outline of the semiconductor light emitting device, and FIG. 2 is an energy band diagram of a conventional quantum well semiconductor laser device. 1... N-type AlAs layer, 2... AlGaAs layer as a radio wave injection layer, 3'' AJIAs layer, 4---
-Light emission
．． 7-... Base quantum level, 8... First excited quantum level, 9.10... Bias power supply, lla, llb.
...Pair of electrodes, 12...Semiconductor substrate. Agent Masuo Oiwa Procedural amendment (voluntary)

Claims (4)

[Claims] (1) An electric field can be applied in the in-plane direction and a direction perpendicular to the plane, and an electric field can be applied in the direction perpendicular to the plane with a quantum well or a light-emitting layer having multiple quantum levels in the conduction band, and A quantum well and a current injection layer are provided adjacent to the light-emitting layer and have a quantum level different from that of the light-emitting layer, and the light-emitting layer is provided with an electrode for extracting electrons stored in the ground level to the outside. A semiconductor light emitting device characterized by comprising: (2) The semiconductor light emitting device according to claim 1, wherein the quantum wells of the light emitting layer and the current injection layer have different barrier heights. (3) The semiconductor light emitting device according to claim 1, wherein the quantum wells of the light emitting layer and the current injection layer have the same barrier height but different well widths. (4) The semiconductor light emitting device according to claim 1, wherein the semiconductor light emitting device has cleavage planes at opposite ends.