JPS58182287A - Double hetero junction type semiconductor laser - Google Patents

Abstract

PURPOSE:To reduce the amount of spontaneous light emission by a method wherein the carrier density of a P type clad layer is set over the fixed value, in a double hetero junction type semiconductor laser equipped with the P type and an N type clad layers respectively by sandwiching an active layer. CONSTITUTION:The double hetero junction type semiconductor laser is equipped with the N type clad layer 2 and the P type clad layer 4 by sandwiching the active layer 3. The both clad layers 2 and 4 have energy band gaps wider than that of the active layer 3, and the light refractive index is set small. In such a semiconductor laser, the relation between the carrier density of the P type clad layer and the amount of spontaneous light emission is when the carrier density becomes 10<18>/cm<3> or more, the amount of spontaneous light emission decreases rapidly. Therefore, the amount of spontaneous light emission can be reduced by selectively the carrier concentration in such a manner.

Description

[Detailed description of the invention] The present invention relates to a double hetero type semiconductor radar.

fI/! The J1 diagram shows a typical machine-ft#, (1
) is an n-type Ga laminate (gallium arsenide) substrate whose main surface is a (100) plane, and (2) is an npGa layered on the first board.
l-xA/xmua (galicum al l arsenic) (0<X<1
), (33 is a non-doped eat-YAl! Y person 8 (
An active layer consisting of 0≦Y<1% y), (4) is deposited on the active layer and PW! P consisting of G&1-Xmu/xAs
(5) may be deposited on the cladding layer. ! A part of the above P-shaped layer (4) has a striped rib shape. In addition, the above n-type cladding layer (!J
The carrier concentration is CL5 to 1X10/j, and the carrier concentration of the P-type cladding layer (4) is approximately -5XIG/-.

The cap layer 15) is formed on the front surface and the back surface of the semiconductor laser f.
When a negative voltage is applied between the cap layer 15) and the P-type cladding layer (4J), the main current path is directly under the first electrode (6). In addition, the n-type cladding layer (2) and the expanded p-type cladding layer (
Since the mu t:arx of 4) is larger than that of the active layer (3), both claddings jl (2) and (4) have a wider forbidden band width and a smaller optical refractive index than the active layer (3). Become.

Therefore, both 1 above! The electrons and positive R injected between the electrodes 16) and ff3 are well confined within the active II (3+) directly below the electrode 16), and are formed by the recombination of the electron layer and holes, which are rejected -f light. It is confined within the active layer (87) which has 4MI, and as a result, it is possible to oscillate the sea f911 with a low current.

However, the above-mentioned conventional semiconductor laser has many spontaneous light-emitting layers, and when used as 5Ija+, the 8/N ratio may be small, and it may be difficult to narrow down the diameter of the slit.

The present invention is an improvement of the above, and is intended to provide a semiconductor sheet with a small number of naturally emitting layers.

The second #A shows the results of 99 experiments conducted by the inventor.

In the experiment, we can investigate the carrier concentration of the P-type cladding layer +43 and the M relationship with the spontaneous luminescent layer by applying 5Pvh to the semiconductor laser f in FIG. 1. #1. In the figure, the horizontal axis shows the medium concentration, and the vertical axis shows the natural light emitting device. As is clear from Fig. 2, when the carrier concentration becomes 1011/- or more, the spontaneous luminescent layer rapidly increases. Find a decrease.

It has been found that even in a pull-hetero type semiconductor sheet, when the carrier concentration of the Pg cladding layer is increased to 101s or more, the spontaneous luminescence layer decreases.

The present invention is based on the knowledge and knowledge that it is possible to reduce the carrier concentration of the above-mentioned PIll flat layer by using a type cladding layer and a double heterojunction layer without a double heterojunction half-body sheath. 10/- or more.

As an actual example, the carrier concentration of the P-type rad layer (4) of the semiconductor laser shown in FIG. 1 will be described below as MX10/-. The P-type impurity in this case is G. (germanicum), and Figure I of the ninth series is PI without the semiconductor laser of Figure III! Kula7Fml(4)e◆+yamt*iwt
o / m width 1 × 10, current-light output characteristics when L is 511 m solid 81. I is big P
Carrier concentration of type Taratu F II (4) $1g1O/
- Member's ink *10 / 'A and the meeting's IIItIJI aru.

Part 1
Ja carrier concentration t'! 5X10"/- when the spontaneous luminescent acid is /J,'
It was found that when f is 5X10"/-, a high sheath output can be obtained at low current (improvement of differential quantum efficiency). This is due to the carrier concentration t-is X 10"/- and high Because of the concentration, the potential energy difference with the active layer [3] is large, ee, and the optical layer refractive index is small, and the hole injection effect is high, tg9.

Modified vcP type modified I (carrier concentration of 4J is 5X1
It has been found that the temperature dependence of the hole transfer rate is more pure in the semiconductor C V with o 18/d, and the temperature dependence of the emission intensity is smaller.

In the general example of this invention, a double heterojunction semiconductor radar made of GtAjAll-based materials has been explained, but as mentioned above, the present invention is based on
It is also applicable to double heterojunction type semiconductor sheets made of other semiconductor sheet materials such as InPs, InAl, and SP.

Furthermore, the present invention is not applicable only to the semiconductor laser having the structure shown in FIG.
Semiconductor rays fWc having other structures are also applicable.

As clearly shown in 1 from the above explanation, since the semiconductor seed of the present invention has less naturally luminescent acid, the radar light @ 8
7 side ratio is large), or the clay light is transmitted to the minute diameter of the slit.
It is also very useful as it allows you to tie it up. Additionally, carrier and light confinement effects, differential quantum efficiency, and temperature dependence are also improved.

[Brief explanation of the drawings] 1st WJ is a cross-sectional view of a typical IFJ & semiconductor semiconductor, 2nd figure is a characteristic diagram showing the relationship i between carriers in the Hiro P-type cladding layer and the spontaneous luminescent layer, and 3rd figure is a current diagram. FIG. 3 is a characteristic diagram illustrating the relationship between and optical output. (21-n-type cladding layer, (8)-active layer, electrode 4)-P
Shaped rad pigeon. Hinoki honing V

Claims (1)

[Claims] (II. The active layer is a double heterojunction semiconductor, with a P-type cladding layer and an n-type cladding layer having a wider p-gband width and a smaller optical refractive index than the active layer above the active layer. A double helical junction type semiconductor laser is characterized in that the carrier concentration of the PI!! cladding layer is 10<7 > or more.