Material

Features Description: The Global Material Library allows for the definition of complex materials using experimental data or parameterized models. The Material Library stores the material data to be used in the simulation. It also provides an interface to change material properties like color, mesh order and so on. User could import materials from Standard Material Library to User Material Library.

Standard & User :Material Library includes Standard Material Material Library and User Material Library.

1 Standard Material Library

The standard material library includes three parts, one is material list, the another is Material Properties, and the another one is the specific material parameters and visual plots. The material list includes a number of common materials. When creating a new simulation, the standard Library will be loaded. And the materials in the Standard Material Library can be imported into User Library. The default materials in the Standard Material Library cannot be edited directly.

1.1 Material List

1. ID : Data ranking index

2. Name : Material Name

3. Mesh Oder: Determine the priority of Boolean operations for overlapping objects in mesh subdivision during simulation,the structures with higher mesh order will cover the structures with lower one

4. Color : The color of materials that can be displayed during modeling structures in the CAD

5. Type : Types of material, including two types, Normal Material and List Data

   Normal Material: Non-dispersive materials

   List Data: Dispersive materials, Materials whose dielectric permittivity changes with wavelength settings, displayed in tabular form.changes with wavelength settings, displayed in tabular form

6. Last Modified :Last modified time

7. Export to User/Export to Project: Export materials in User Library or Project Library

8. Export Data: Export the data of user-selected materials

1.2 Materials in the Standard Material Library

The following materials are included in the standard material Library.

ID	Name	Mesh Order	Type
1	Air	2	Normal Material
2	Al (Aluminium) Palik	2	List Data
3	Al (Aluminium) CRC	2	List Data
4	Au (Gold) CRC	2	List Data
5	Au (Gold) Johnson and Christy	2	List Data
6	Au (Gold) Palik	2	List Data
7	Ge (Germanium) CRC	2	List Data
8	Ge (Germanium) Palik	2	List Data
9	Si (Silicon) Palik	2	List Data
10	SiO2 (Glass) Palik	2	List Data
11	Si3N4 (Silicon Nitride) Kischkat	2	List Data
12	Si3N4 (Silicon Nitride) Phillip	2	List Data
13	Ag (Silver) CRC	2	List Data
14	Pt (Platinum) Palik	2	List Data
15	Ta (Tantalum) CRC	2	List Data
16	TiN Palik	2	List Data
17	Cu (Copper) Palik	2	List Data
18	Fe (Iron) CRC	2	List Data
19	W (Tungsten) CRC	2	List Data
20	Ti (Titanium) Palik	2	List Data
21	Ti (Titanium) CRC	2	List Data
22	Sn (Tin) Palik	2	List Data
23	H2O (Water) Palik	2	List Data
24	Cr (Chromium) CRC	2	List Data
25	Pd (Palladium) Palik	2	List Data
26	InAs Palik	2	List Data
27	Ag (Silver) Palik (1-10um)	2	List Data
28	Ag (Silver) Johnson and Christy	2	List Data
29	W (Tungsten) Palik	2	List Data
30	Fe (Iron) Palik	2	List Data
31	Cr (Chromium) Palik	2	List Data
32	Al2O3 Palik	2	List Data
33	In (Indium) Palik	2	List Data
34	Cu (Copper) CRC	2	List Data
35	Ni (Nickel) CRC	2	List Data
36	V (Vanadium) CRC	2	List Data
37	InP Palik	2	List Data
38	GaAs Palik	2	List Data
39	Ni (Nickel) Palik	2	List Data
40	Rh (Rhodium) Palik	2	List Data
41	Ag (Silver) Palik (0-2um)	2	List Data
42	PEC	2	PEC

1.3 Material Properties

Plot :User can view each material property in this plot area via clicking a certain material in material list, also can view properties they are interested in via two options in the bottom of plot. Material properties include “Color”, “Name”, “Mesh Order”, “Wavelength”, “Frequency”, “n,k”-Re(refractive index) & Im(refractive index), “εr′,εr″-Re(relative permittivity) & Im(relative permittivity), “εr′,σ”-Re(relative permittivity) & conductivity.

Material Data Tab: User can view each material property in this list via double clicking a certain material in material list. Material properties include “Color”, “Name”, “Mesh Order”, “Wavelength”, “Frequency”, “n,k”-Re(refractive index) & Im(refractive index), “εr′,εr″-Re(relative permittivity) & Im(relative permittivity), “εr′,σ”-Re(relative permittivity) & conductivity.

1.4 Electrical Material Properties

Electrical Materials in the Standard Material Library:

The following materials are included in the standard material Library.

ID	Name	Mesh Order
1	Air (Electrical)	2
2	Aluminum(Electrical)	2
3	Germanium(Electrical)	2
4	Silicon(Electrical)	2
5	SiO2(Electrical)	2

Material Properties:

Material properties in electrical engineering include attributes such as "Name," "Color," and "Mesh Order," alongside various electrical parameters specific to each material type. Users are required to define permittivity for “Insulators” or work functions for “Conductors”. Semiconductors necessitate the definition of multiple parameters, encompassing DC permittivity, work function, as well as fundamental aspects like effective mass/density of states, band gap model, mobility, and recombination. It's worth noting that users cannot modify these parameter values in the standard library, except within the user library or objects tree.

2 User Material Library

Feature Description:The User Material Library, a library that stores user-customized material data. It includes two parts, one is material list, and another is material properties. User can copy or delete a selected material, and also can export material data according to their needs.

2.1 Material List

1. ID : Data ranking index

2. Name : Material Name

3. Mesh Oder: To determine the priority of the Boolean operation for overlapping objects during grid dissection, the structures with higher mesh order will cover the structures with lower one

4. Color : The color of materials that can be displayed during modeling structures in the CAD

5. Type : Types of material, including two types, Normal Material and List Data

   Normal Material: Non-dispersive materials.

   List Data: Dispersive materials, Materials whose dielectric permittivity changes with wavelength settings, displayed in tabular form.changes with wavelength settings, displayed in tabular form.

6. Last Modified :Last modified time

7. Import Data: Import materials data to User Material Library.

8. Export Data: Export materials data according to user needs.

2.2 Material Properties

Plot : User can view each material property in this plot area via clicking a certain material in material list, also can view properties they are interested in via two options in the bottom of plot, Such as "Wavelength", "Frequency",“n,k”-Re(refractive index) & Im(refractive index), “εr′,εr″-Re(relative permittivity) & Im(relative permittivity), “εr′,σ”-Re(relative permittivity) & conductivity.

Material Data Tab: User can view each material property in this list via double clicking a certain material in material list.Material properties include “Color”, “Name”, “Mesh Order”, “Wavelength”, “Frequency”, “n,k”-Re(refractive index) & Im(refractive index), “εr′,εr″-Re(relative permittivity) & Im(relative permittivity), “εr′,σ”-Re(relative permittivity) & conductivity.

Anisotropy : Two options in this drop-down menu, “None” and “Diagonal”, when diagonal option is checked, user can create FDTD, FDE, or EME anisotropic optical material in the “User Material Library” window. Anisotropic materials react to electric field with directional dependent electric displacement. Permittivity $\varepsilon_{ij}$ can be represented by a 9 element tensor. 

$$D_i = \varepsilon_{ij}E_j$$

In general, this tensor can be diagnonalized by a proper choice of coordinate system, e.g. in principle dielectric axes. So it is simplified to

$$\varepsilon =\begin{bmatrix} \varepsilon_x & 0 & 0\\ 0 & \varepsilon_y & 0\\ 0 & 0 & \varepsilon_z \end{bmatrix}$$

Diagonal anisotropic materials:To define an anisotropic material, set the Anisotropy in the material Library to Diagonal and assign the parameters for each diagonal component.

2.3 Electrical Material Properties

To conduct simulations accurately, users are required to specify various electrical parameters and models corresponding to different material types. For insulators, defining permittivity is essential, while for conductors, specifying work function is necessary. When dealing with semiconductors, users have the flexibility to define DC permittivity, work function, and fundamental parameters including mobility and recombination.

In addition to the properties mentioned above, users can also define temperature dependencies for many parameters using the adjacent "f(T)" buttons. This action triggers a parameter editor displaying the associated formula.

Name: Users have the option to redefine the name of the material.

Color: Users can choose a different color to represent the material in the layout.

Mesh Order: Determines the meshing of overlapping objects in the simulation.

Material Type: There are three material types: Insulator, Conductor, and Semiconductor.

Permittivity/DC Permittivity: Specifies the relative dielectric permittivity of the material, represented by a 3x3 matrix.

Work Function: Specifies the intrinsic work function of the material. Failure to specify a work function will result in Ohmic contacts irrespective of the material.

Fundamental: Semiconductors must have basic properties defining their electronic behavior, including relative band gap, effective mass, or density of states.

Effective Mass/Density of States: Users can specify the effective mass of electrons and holes, as well as the density of states for the conduction and valence bands.

Band Gap: Users can specify the band gap at 300K and choose a model of bandgap narrowing from the available options. The effective intrinsic carrier concentration (Ni) is calculated by combining the effective mass or equivalent density of states.

Mobility: Defines the mobility of electrons and holes, accounting for corrections due to scattering and supporting velocity saturation effects under strong electric fields.

Lattice and Impurity Scattering: User can define the low-field mobility model of electrons and holes at lattice, correct the charge carriers from lattice thermal vibration scattering at “f(T)”. The Masetti model in the pull-down box of impurity to correct the heavier doped scattering.

High Field: Users can opt for the Canali model to calculate mobility changes due to the drift speed reaching saturation under the influence of strong electric fields in the semiconductor. To specify the carrier's saturation velocity (vsat), users need to select either the size of the Quasi-Fermi level gradient or the component of the electric field in the direction of the current density from the "Driving Field" drop-down box.

Recombination: The continuous transition and recombination of different bands are crucial in simulation design. Users can enable or disable the corresponding composite model based on their preferences.

Trap-Assisted(Rsrh): Users can activate the trap-assisted composite, allowing them to directly define the temperature-dependent lifetime of electrons and holes or correct it using the carrier concentration-dependent Scharfetter model or the field effect model Schenk.

Radiative(Ropt): Users can activate the Radiative model and define the parameters of copt.

Auger(Rau): Users can enable auger recombination of band-to-band, which is temperature-dependent by activating the "Enable Model" option.

Band to Band Tunneling: Users can activate the band-to-band tunneling model of Hurkx or Schenk.

3 New Material

Features Description: Create a new material and set its property parameters. The newly created material can be saved to the User Material Library using "Export to User" or it can be directly imported into the project using "Export to Project".

Plot : User can view each material property in this plot area via clicking a certain material in material list, also can view properties they are interested in via two options in the bottom of plot, Such as "Wavelength", "Frequency",“n,k”-Re(refractive index) & Im(refractive index), “εr′,εr″-Re(relative permittivity) & Im(relative permittivity), “εr′,σ”-Re(relative permittivity) & conductivity.

Anisotropy : Two options in this drop-down menu, “None” and “Diagonal”, when diagonal option is checked, user can create FDTD, FDE, or EME anisotropic optical material in the “User Material Library” window. Anisotropic materials react to electric field with directional dependent electric displacement. Permittivity $\varepsilon_{ij}$ can be represented by a 9 element tensor. 

Diagonal anisotropic materials:To define an anisotropic material, set the Anisotropy in the material Library to Diagonal and assign the parameters for each diagonal component.