JPS60143678A - Light emitting transistor - Google Patents

Abstract

PURPOSE:To obtain an element construction enabling light emission of two wave lengths or a laser oscillation by laminating light emitting devices into a construction of transistor. CONSTITUTION:In a light emitting transisror of n-p-n three-electrode construction, if the forward direction current flows between the electrodes 11, 12, the nnu light emissionis obtained and if the forward direction current also flows between the electrodes 13, 11, the nnu' light emission is obtained. By combining the crystal compositions of the p-n junction, different wave lengths can be obtained simultaneously and a light emitting transistor which emits two wave lengths with a construction of one semiconductor device is formed. If, for example, a current flows between the electrodes 11, 12 emitting the light of nu' and the voltage of a signal is applied between 11, 13 or 12, 13, such a construction of device can also modulate the intensity of light emission between 11, 12 and by coupling the light emission between 11, 12 and the light emission between 12, 13, makes multicoloring by subtractive color mixture possible.

Description

Detailed Description of the Invention (a) Technical Field of the Invention The present invention relates to a light emitting transistor mounting a photoelectric conversion element on a compound semiconductor substrate, and particularly relates to a structure of a light emitting element that is easy to obtain three wavelength light emission. 〇(b) Background of the Technology Normally, an element-1 conversion element such as a laser diode (LD) or a light emitting diode has a bipolar structure of a PN junction. Oscillation or light emission is caused by passing a forward current through the PN junction. The potential barrier of the PN junction is lowered by the forward bias, and electrons flow from the N shadow region to the P shadow region, and holes flow from the P shadow region to the N shadow region.
The holes recombine in the injected region and release an element (Eg = h-■) corresponding to the energy gap (Bg) of the semiconductor. The difference between a light emitting diode and a laser diode is that the former emits light by natural numbering, whereas the latter emits light by stimulated emission.

Therefore, the current density of a laser diode is an order of magnitude higher than that of a light-emitting diode, and its structure has two planes perpendicular to the PN junction plane, and the light emitted from the active region is emitted while traveling back and forth between these two reflecting planes. A laser beam with a wavelength determined by this reflective surface is grown, and this laser beam is extracted to the outside.

Used in the formation of light emitting diodes (Ja As l
-XPx is gallium arsenide (GaAs) and gallium phosphide (
It is well known that the direct or indirect transition type is eliminated by the capacitance of X. That is, 0≦X<0
．． 45 is a direct transition form, 0.45 (x≦1 has an indirect transition form kenstopte @, GaAs (infrared), GaAsP (red)
, Ga P (red, yellow, green), etc. are often used.

On the other hand, laser diodes have been confirmed to oscillate over a wide range from visible to far infrared, in addition to GaAs lasers. The infrared diode laser uses a semiconductor substrate with a small energy gap (Eg), and the oscillation wavelength can be changed continuously from the outside by changing temperature, pressure, magnetic field, and diode current! Among the long-lasting infrared conductor lasers, lead chalcogenide (Pb8an, pb8nTe) infrared conductor lasers are attracting attention because of their wavelength tunability over a wide range.

(C) Prior Art and Problems FIG. 1 is a block diagram showing an example of a conventional GaP green light emitting diode, and FIG. 2 is a block diagram showing an example of a lead chalcogenide-based infrared conductor laser.

In the first step, an n-type GaP epitaxial layer 2 and a p-type GaP epitaxial layer 3 are laminated on an n-type GaP substrate 1 doped with sulfur (S) or tellurium (Te).

The n-type OaP epitaxial layer 2 is doped with 8 or Te, which is the same impurity as the substrate 1, to form an n-type layer, and the P-type GaP epitaxial layer 3 is doped with zinc (Zn) to form a P-type layer. N-type and P-type epitaxial J So 2. :H
1 to 2 x 1018Crn-3ON atoms are added to this, and therefore the green light emission is caused by phosphorus atoms (Pl) that make up the crystal.
Luminous efficiency is expressed by taking the N atom that replaces the lattice position of the luminescent center as the luminescent center. The NJfA child that replaced P has the same Vgl as P.
Since this is p4, electrically 1 is neutral, but since the electrical resistance of N is greater than P, isoelectronic wrap (
When excitons captured by this act as an electronic trap are annihilated, green light is emitted.

The electrode consists of an upper P[m4 and a lower n′i[pole 5, both [
By passing a forward current l between the poles 4 and 5, the desired green light emission can be obtained, but there is only one emission source that is harmful to the l element.

In Fig. 2, an n-type Pb1-
P and n-type P b 'I' e layers 7 and 9 sandwiching the e layer 8
By determining the OX value to form the infrared laser of a predetermined oscillation wavelength.

3- The n-type Pb1ysnXTe layer 8 forms an active layer and is P-type.

When the blood layer is formed, the n-type Pb'l'e/d 7,9 is used to excite the active layer with more infrared laser by passing a forward current in the upper part and the lower part'. In this case as well, infrared light oscillation is performed with one wavelength corresponding to the l-chord, similar to the above-mentioned light emitting diode.

The present inventors focused on a transistor structure in which these photoelectric conversion elements are stacked to obtain three-wavelength light emission or oscillation.

(d) Purpose of the Invention In view of the above points, the present invention aims to provide a device structure in which a light emitting device is stacked to form a transistor structure and enables three-wavelength light emission or laser oscillation.

tel Structure of the Invention According to the present invention, the above object includes a first compound semiconductor layer of 14-electroconductivity type, a second compound semiconductor layer of anticonductivity type formed on the first compound semiconductor layer, It has a third compound semiconductor N of conductivity type formed on the second compound semiconductor layer, and is transported by emitting light at the valley junction.

4-(f) Embodiment of the Invention Figure 3 shows the basic configuration of a light-emitting transistor having a triode structure, which is an embodiment of the invention, and Figure 4 shows an embodiment of the invention. FIG. 5 is a schematic diagram illustrating the energy gap at the Pn junction in FIG. 4, which is a block diagram of a certain three-wavelength infrared conductor device.

As shown in Fig. 3, when a forward current is passed between electrodes lt and 12 in a light-emitting transistor with a triode structure of n-P and -n, light emission of bv is obtained, and similarly between electrodes 13 and 11. By passing a forward current, light emission of hr' can be obtained.

By combining the crystal composition of this P-n junction,
Since different wavelengths can be obtained simultaneously, a light emitting transistor capable of emitting light at three wavelengths can be formed with one semiconductor device configuration.

By adopting such a device configuration, for example, the electrode 1
1. While applying electricity for 12 seconds to emit hv' light, 11.
By applying a signal voltage between 13 and 12.13, the light emission intensity between 11.12 and 12.13 can be modulated, and by coupling the light emission between 11.12 and the light emission between 12° and 13. 1181 Multicoloring due to subtractive color mixing
' Become capable.

The one shown in Figure 4 constitutes an infrared semiconductor that forms a double double heterojunction, with Pn junctions arranged on both sides in contact with the active layer, making it a double structure, and forming electrodes corresponding to each n. This shows an example in which the semiconductor has a two-system structure.

A Pb5nTe layer 14.15 is provided in the active layer, and an n-type cladding layer (n-PbT
e layer) 16, P-shaped rad layer (1'-PbTe layer) 18
will be established. Similarly, on the second element (I3) side, there is also an l-type cladding layer (n-Pb'l'e layer) 17 and a p-type cladding layer (P-PbTeffi) 1 shared with the first element (5).
Consists of 8.

The electrode configuration is such that the first element (AlNil has an upper electrode 19 and a lower electrode 22) and the second element (B) side has an upper electrode 21 and a lower electrode 20, making it a two-element configuration. be.

In this example, the thickness of each layer is 1 μm, and the n-type rad layers 16 and 17 are made of bismuth (Bi) or indium (I).
n) Y, while the active layer 14 is doped with tellurium (Te) in the P-type cladding layer 18.
．． 154 No impurity implantation is performed here. A desired three-wavelength laser can be obtained by setting the carrier concentration to 1015 -3 and applying about OLV between the electrodes.

As shown in FIG. 5, the generation efficiency can be improved by forming a double tuple heterojunction. That is, as is clear from the figure, the gap energy gap (Eg) between the conduction band 23 on the electron side and the valence band 24 on the hole side is narrow for 1 Pb Sn Te7i114 and wide for 15yrEg P b Te Nil b + 17 It has a structure sandwiched by .18, and two Pb5nTe J so14, l
5 is the light emitting region (f5 layer) t of the first element and the second element, respectively.
Since no photons are emitted, the luminous efficiency can be increased.

In this example, the N-P-N type was explained, but the P-N-
Of course, the P type may also be used.

By using an electric conversion cable, it becomes possible to modulate or emit light with three wavelengths, and the range of application is expanded, such as making it easier to create various signal plates.

[Brief explanation of drawings]

Fig. 1 is a block diagram showing an example of a conventional GaP green light emitting diode, Fig. 2 is a block diagram showing an example of a lead chalcogenide-based infrared semiconductor laser, and Fig. 3 is a block diagram showing an example of a lead chalcogenide-based infrared semiconductor laser. FIG. 4 is a schematic diagram showing the basic configuration of a light-emitting transistor, which is an embodiment of the present invention. FIG. FIG.゛11-13 in the figure. 19-22... River... 1L pole, 1
4.15...----PbSnTe layer (active layer)
l 6 , 17 , l 8 ----------...PbT
e layer (cladding layer), 23... light... conduction band, 24...
・・・・・・・・・Valence band. Tei 1 Prisoner Tei, SujY-5Ko

Claims (1)

[Claims] a first compound semiconductor layer of a conductive plate, a second compound semiconductor layer of an opposite type formed on the first compound semiconductor layer, and a second compound semiconductor layer formed on the second compound semiconductor layer; A light-emitting transistor comprising a third compound semiconductor layer of one conductivity type and emitting light at each junction.