Learning Forum

[Bharathy J]

Dear Sir/ Madam,

I am using Lumerical Charge for the first time. To replicate the results of a research paper, I want to add a new material, Indium Tin Oxide (ITO), to the material database. In the paper, ITO is considered as a semiconductor, and the following material properties are provided: (i) DC permittivity, (ii) Work function, (iii) Effective mass of electrons and holes, (iv) Mobility of electrons and holes, (v) Band gap, and so on.

However, when I input these parameters and run the simulations, I encounter a Job Error. Upon closer inspection, I noticed that each parameter, such as the effective mass of electrons or holes, is associated with a formula. It appears that the coefficients within these formulas need to be appropriately adjusted to balance the equation.

For example, for silicon (Si), the effective mass of an electron is 1.18, and the corresponding formula is m(T) = m(0) + α*T + β*T^2. The left-hand side value of 1.18 must be balanced with the right-hand side by selecting appropriate coefficients α, β, and m(0). Similarly, for each parameter, there is a formula with coefficients that need to be adjusted to balance the equation on both sides.

My question is: How should I determine these coefficients? Should they be adjusted arbitrarily, or are there specific literature or guidelines I should refer to obtain accurate values?

Could you please provide some guidance on this matter?

Kind regards,
Bharathy J

[Guilin Sun]

The coefficients are built-in that you can modify:

If you do not know the coefficients, simply use the default values from the material database. For any new materials, you may need to find them from literature, or "borrow" from similar materials, with possibly reasonable modifications if you can.

As for the job error, most likely the material properties are not complete, or improper. You can borrow the parameters and check if the new material works for example Si, before testing ITO material. Once it works, then try the ITO again with proper parameters. 

As for what is "proper", it is hard to justify here since this is material property, which is inherent from the material its self. It is better to know the material before simulation.