[[NOTE:]] MQW script commands (mqwgain, buildmqwmaterial, and mqwindex) are no longer being actively developed. Please use the MQW solver object from Ansys Lumerical Multiphysics™ to access the newest features (such as 6x6 and 8x8 \(k\cdot p\) methods). The MQW solver object also allows you to set its properties using script and requires the same licenses as the script commands.
Creates a struct with material parameters for use with mqwgain and mqwindex commands.
| Syntax | Description |
|---|---|
| result = buildmqwmaterial(location, T, matname, x); |
Ternary materials. location: string specifying the path to the database file. Alternatively, if empty struct, the default database will be used. T: temperature. matname: ternary material name. x: material composition. result: struct with material properties. |
| result = buildmqwmaterial(location, 300, matname, x, cbValley); | same as above with the additional parameter cbValley that specifies which conduction band valleys will be included for the interpolation of parameters. Possible values: “Gamma”, “X”, “L”, or “All” (default is “Gamma”; option “All” uses the lowest band gap to select). |
| result = buildmqwmaterial(location, 300, matname, x, y); | Quaternary material with compositions x and y. |
| result = buildmqwmaterial(location, 300, matname, x, y, cbValley); | Quaternary material with compositions x and y and the valley mixing specifier. |
The supported materials are listed in the table below:
| III-V semiconductors | Ternary alloys | Quaternary Alloys |
|---|---|---|
| AlAs | AlxGa1-xAs | InxGa1-xAsyP1-y |
| GaAs | AlxGa1-xP | AlxGayIn1-x-yAs |
| InAs | AlxIn1-xP | |
| AlP | GaAsxP1-x | |
| GaP | InxAl1-xAs | |
| InP | InAsxP1-x | |
| InxGa1-xAs | ||
| InxGa1-xP |
When database materials are used, the properties of ternary alloys P(AxB1−xD) are interpolated from the corresponding properties of the base materials (P(AD) and P(BD)) according to the formula
$$ P\left(A_x B_{1-x}D\right)=xP\left(AD\right)+\left(1-x\right)P\left(BD\right)+x\left(1-x\right)C, $$
where x is the composition fraction and C is the bowing parameter (quadratic coefficient).
Quaternary alloys of type AxB1-xCyD1-y (two group III and two group V elements) are composed from the interpolation of ternary alloy constituents [1]:
$$ P\left(A_xB_{1-x}C_yD_{1-y}\right)=\frac{x\left(1-x\right)\left[\left(1-y\right)P\left(A_xB_{1-x}D\right)+yP\left(A_xB_{1-x}C\right)\right]+y\left(1-y\right)\left[xP\left(AC_yD_{1-y}\right)+\left(1-x\right)P\left(BC_yD_{1-y}\right)\right]}{x\left(1-x\right)+y\left(1-y\right)}, $$
for composition fractions x and y. For example, a combination of the properties of InxGa1−xP, InxGa1−xAs, InAsyP1−y, and GaAsyP1−y is used to define the properties of InxGa1−xAsyP1−y.
Quaternary alloys of type AxByC1-x-yD (three group III elements and one group V element) are composed from the interpolation of ternary alloy constituents [1]:
$$ P\left(A_xB_yC_{1-x-y}D\right)=\frac{xyP\left(A_{1-u}B_uD\right)+y(1-x-y)P\left(B_{1-v}C_{v}D\right)+x(1-x-y)P\left(A_{1-w}C_{w}D\right)}{xy+y(1-x-y)+x(1-x-y)}, $$
for composition fractions x and y and u = (1-x+y)/2, v = (2-x-2y)/2, w = (2-2x-y)/2. For example, a combination of the properties of Al1-uGauAs, Ga1-vInvAs, and Al1-wInwAs, is used to define the properties of AlxGayIn1-x-yAs.
result is a struct with the following fields:
| Coefficient | Units | Description |
|---|---|---|
| eg | eV | Band gap |
| ep | eV | Energy parameter for the optical matrix element |
| me | 1/m0 | Electron effective mass |
| gamma1 | Luttinger parameter | |
| gamma2 | Luttinger parameter | |
| gamma3 | Luttinger parameter | |
| ac | eV | Conduction band deformation potential |
| av | eV | Valence band deformation potential |
| b | eV | Valence band deformation potential |
| c11 | N/m2 | Elastic stiffness coefficient |
| c12 | N/m2 | Elastic stiffness coefficient |
| lc | m | Lattice constant |
| vb | eV | Valence band absolute energy (all layers should have common reference) |
| eps | Relative static permittivity |
References
[1] Vurgaftman et al., J. Appl. Phys., 89, 5815 (2001)
Example
mymat = buildmqwmaterial(“/home/auser/myfolder/my_material_db.json”, 300, “InAlAs”, 0.47);See Also