# Knowledge Base

 Navigation: Scripting Language > Functions buildmqwmaterial

Creates a struct with material parameters for use with mqwgain command.

 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 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 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.

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)

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);