This section describes how to create a new alloy material model in the Electrical and Thermal material database. For details on the Semiconductor material input parameters, see the Semiconductor material model page. For details about the alloy interpolation options and bowing parameters, see the Alloys material model page.
While the Electrical/Thermal material database contains models for many common alloys, it may be necessary to add new alloy models for different systems. This section will describe how to set the minimum parameters necessary for a new alloy model. A new alloy can be added to the material database by opening the material database and choosing the "Ternary Alloy" or "Quaternary Alloy" option from the "new material" button menu. The newly defined alloy can be named and a color can be chosen to represent the material in the layout.
Once a new ternary alloy material is created, the base materials can be selected using the pull down menus. Any two semiconductor materials from the material database can be selected to create a ternary alloy. The first semiconductor assumes mole fraction (1-x) and the second one, x. Once the base materials are selected, the interpolation type with respect to multiple valleys and various interpolation bowing parameters can be defined. To learn about these interpolation options, see the Alloys material model page.
Once a new quaternary alloy material is created, the interpolation type can be selected that corresponds to the type of quaternary. There are two interpolation types available, see the Alloys for details. After that, the base materials can be selected using the pull down menus. Alternatively, by entering the formula for a III-V quaternary material in the form ABCD, base ternary compounds can be automatically selected by clicking "Update". The allowed atomic species in ABCD are Al, Ga, In, As, P, N, and Sb. For some quaternaries, the band gap at room temperature can be set to use formulas from reference  instead of using default interpolation, in order to increase accuracy.
Send to Current Project
Using the instructions above, the newly created alloy will be added to the Electrical/Thermal material database. To use the newly created alloy, or an existing alloy, in the simulation, it can be added to the object tree by using options in the Send to Current Project frame in the bottom left corner of the Electrical/Thermal Material Database edit window. Option "create new" with the appropriate name specified in the text box can be used to add alloy directly to the simulation. Option "create semi" first converts the alloy to Semiconductor type for the specified x, or x and y, alloy composition and then adds the semiconductor material to the object tree. By using this option the users can see all the relevant semiconductor option values, such as band gap, effective mass, mobility, and others. Option "add to existing" adds the alloy to an existing material in the object tree. Only the materials in the object tree that do not already have properties defined are available for this options. Not all of these options may be available, depending on the type of material.
- Shun Lien Chuang, Physics of Optoelectronic Devices. John Wiley & Sons Inc, (1995).