Appendix C GAIN Examples
In this
appendix, the use of the GAIN program is demonstrated for ten material
systems. Each section below contains an
example of how GAIN is used with one of these material systems.
C.1. Material system #1:
AlGaAs/ AlGaAs
This is a
simulation of a five-layer laser structure that contains a single quantum well
(QW), two separated confinement heterostructure (SCH) layers, and two cladding
layers as shown in Fig. C.1.1.
Figure
C.1.1. Energy band diagram for the simple quantum well
structure
C.1.1. Calculation of material compositions and energy band edges.
The first step of the GAIN program is to
calculate the material compositions and energy band edges of the each layer.
The user is asked to enter the photoluminescence wavelength, thickness, and
strain of the QW, SCH, and cladding layers. After these parameters are input,
the GAIN program generates two output files: cbandeg.dat and vbandeg.dat,
containing the material compositions, and the conduction band edges and valence
band edges respectively. The detailed explanation is provided in Chapter 2 of
this manual.
a) The input parameters to the GAIN program in this step islisted in Table.
C.4.1.
Table
C.4.1. Input parameters to the GAIN program in this step.
|
Layer |
l (um) |
Strain |
Thickness (Ǻ) |
|
QW (AlxGa1-xAs) |
0.87 |
------ |
50 |
|
SCH (AlxGa1-xAs) |
0.74 |
------ |
60 |
|
Cladding (AlxGa1-xAs) |
0.58 |
|
100 |
b) The steps in using the GAIN program to
calculate the material compositions and energy band edges are listed in Table
C.1.2
Table C.1.2. steps to run
the GAIN program for necessary parameters.
|
ENTER 1 FOR THE NECESSARY PARAMETERS 2 FOR THE ENERGY VALUES OF CONDUCTION
BAND 3 FOR THE ENERGY VALUES OF HEAVY HOLE
BAND 4 FOR THE ENERGY VALUES OF LIGHT HOLE
BAND 5 FOR THE LASER G-J AND G(LAMBDA) 6 FOR RATE EQUATIONS(TWO SECTION MODEL
INCLUDED) 7 FOR EXIT 1 ENTER 1 FOR AlGaAs/AlGaAs 2 FOR InGaAsP/InGaAsP/InP 3 FOR InGaAs/InGaAsP/InP 4 FOR InGaAlAs/InGaAlAs/InP 5 FOR GaInP/(AlGa)0.5In0.5P/AlInP 6 FOR InGaAs/AlGaAs/AlGaAs 7 FOR
InGaAs/InGaAsP/Ga0.51In0.49P(MATCHED GaAs) 8 FOR AlyInxGa1-x-yAs/AlzGa1-zAs/GaAs 9 FOR InzGa1-zAs/AlyGaxIn1-x-yAs/InP 10 FOR InGaAlAs/InGaAlAs/AlAsxSb1-x(matched
InP) 11 FOR
InzGa1-zAs/AlyGaxIn1-x-yAs/AlAsxSb1-x 12 FOR In(y)Ga(1-y)As(x)N(1-x)/GaAs
(dilute N) 13 FOR In(1-x)Ga(x)As(y)P(1-y)/GaAs 14 FOR EXIT, BACK TO MAIN PAGE! 1 INPUT THE LAYER # FOR GRIN STRUCTURE(STEP) STEP N= 2 INPUT THE WELL WAVELENGTH (um) 0.87 INPUT THE BARRIER WAVELENGTH (um) 0.74 INPUT THE CLADDING WAVELENGTH (um) 0.58 BANDGAP ENERGY OF QUANTUM WELL= 1.42528735632184 eV INPUT CLADDING, BARRIER,QUANTUM WELL WIDTH
(A) 100 60 50 WRITE CONDUCTION BAND PARAMETERS INTO
CBANDEG.DAT WRITE INPUT 1 FOR NEW CALCULATION 2 FOR EXIT INPUT =? 2 ENTER 1 FOR AlGaAs/AlGaAs 2 FOR InGaAsP/InGaAsP/InP 3 FOR InGaAs/InGaAsP/InP 4 FOR InGaAlAs/InGaAlAs/InP 5 FOR GaInP/(AlGa)0.5In0.5P/AlInP 6 FOR InGaAs/AlGaAs/AlGaAs 7 FOR
InGaAs/InGaAsP/Ga0.51In0.49P(MATCHED GaAs) 8 FOR AlyInxGa1-x-yAs/AlzGa1-zAs/GaAs 9 FOR InzGa1-zAs/AlyGaxIn1-x-yAs/InP 10 FOR InGaAlAs/InGaAlAs/AlAsxSb1-x(matched
InP) 11 FOR
InzGa1-zAs/AlyGaxIn1-x-yAs/AlAsxSb1-x 12 FOR In(y)Ga(1-y)As(x)N(1-x)/GaAs
(dilute N) 13 FOR In(1-x)Ga(x)As(y)P(1-y)/GaAs 14 FOR EXIT, BACK TO MAIN PAGE! 14 THIS PROGRAM STOP HERE!, BACK TO MAIN PAGE |
c) The output files, cbandeg.dat and
vbandeg.dat are explained in Table C.1.3.
Table C.1.3. Material
compositions and band offsets:
a) cbandeg.dat for conduction band
|
************************************************************************ QW
strain lattice constant 0.000000E+00
0.565311E-09 material
compositions layer
thickness, Al
conduction band edges
0.10000000E+03 0.56115438E+00 0.0000000 0.4632184 cladding layer
0.60000000E+02
0.20182492E+00
0.0000000 0.1627524 SCH layer
0.50000000E+02
0.10323627E-02
0.0000000 0.0000000 quantum well
0.60000000E+02
0.20182492E+00 0.0000000 0.1627524 SCH layer
0.10000000E+03
0.56115438E+00
0.0000000 0.4632184 cladding layer ************************************************************************ |
b) vbandeg.dat for valence
band
|
****************************************************
******************** QW
strain lattice constant 0.000000E+00
0.565311E-09 material
compositions layer
thickness, Al valence
band edges
0.10000000E+03
0.56115438E+00
0.0000000 -0.2494253 cladding layer
0.60000000E+02
0.20182492E+00
0.0000000 -0.0876359 SCH layer
0.50000000E+02
0.10323627E-02
0.0000000 0.0000000 quantum well 0.60000000E+02 0.20182492E+00 0.0000000 -0.0876359 SCH layer
0.10000000E+03
0.56115438E+00
0.0000000 -0.2494253 cladding layer ************************************************************************ |
C.1.2. Energy level calculations
After the calculation of the material
compositions and energy band edges, the GAIN program calculates energy levels
in the conduction band and valence bands. The detailed explanations are
discussed in Chapter 3 of this manual.
a) The steps of how to calculate the energy
levels are shown in Table C.1.4.
Table C.4.4. Steps to
calculate the energy levels
i) Steps to calculate the
conduction band energy levels
|
ENTER
1 FOR THE NECESSARY PARAMETERS 2 FOR THE ENERGY VALUES OF
CONDUCTION BAND 3 FOR THE ENERGY VALUES OF HEAVY HOLE
BAND 4 FOR THE ENERGY VALUES OF LIGHT HOLE
BAND 5 FOR THE LASER G-J AND G(LAMBDA) 6 FOR RATE EQUATIONS(TWO SECTION MODEL
INCLUDED) 7 FOR EXIT 2 INPUT THE NUMBER OF QUANTUM WELLS NUM=? 1 INPUT TOTAL LAYERS FOR STRUCTURE--N ODD INPUT N= 5 INPUT THE LOWEST POTENTIAL LAYER(1st
Q-WELL) IC= ? 3 INPUT THE SELECTED CENTER LAYER OF
STRUCTURE ICR= 3 ******************************************************* INPUT I=1 FOR AlGaAs I=2
FOR InGaAsP I=3
FOR In1-xGaxAs/InGaAsP/InP I=4
FOR InGaAlAs/InGaAlAs I=5
FOR GaInP/(AlGa)0.5In0.5P/AlInP I=6
FOR InGaAs/AlGaAs/AlGaAs I=7
FOR InGaAs/InGaAsP/Ga0.51In0.49P(GaAs) I=8
FOR AlyInxGa1-x-yAs/AlzGa1-zAs/GaAs I=9
FOR InzGa1-zAs/AlxGayIn1-x-yAs/InP I=10 FOR
InGaAlAs/InGaAlAs/AlAsxSb1-x(InP) I=11 FOR
InzGa1-zAs/AlxGayIn1-x-yAs/AlAsxSb1-x |