Learning Forum

[nuaman]

I am totally confused with the MQW solve. i couldn't add layers in the MQW solver. also i saw many parameters in the KdotP, where i can find those values?

[Khashayar Ghaffari]

Hi Thanks for reaching out. We donÔÇÖt have a video tutorial for MQW but all the related documents and instructions are linked in the MQW reference manual. Specifically for K dot P parameters I suggest looking into this article which provides description on each parameter and how the buildmqwmaterial command can be used to generate them. Regarding adding layers, could you please elaborate on what the issue is youÔÇÖre having? Are you adding layers in the GUI? Sharing screenshots can be helpful.
Best regards

[nuaman]

Thankyou for your reply.
what i meat with adding layers is that in the MQW solver edit window. there are some strain and valance band details to be entered.
Also is it possible to have a live session on MQW solver to make use of it completely?

[nuaman]

How to change the crystal structure from zinc blende to wurtzite?

[Khashayar Ghaffari]

I recommend looking into the reference manual mentioned earlier. Instructions for defining strain and valence band offset are presented in these articles respectively:
https://support.lumerical.com/hc/en-us/articles/4408545925011
https://support.lumerical.com/hc/en-us/articles/4408314622099#toc_6
Currently only materials with zincblende structure are supported in MQW (more information about creating materials for MQW is provided here)
Right now there are no MQW training sessions scheduled.
Best

[nuaman]

Hi How can I find the units of the attributes in the result visualize windows.
For example, what is the unit of emission in the below image. (also the unit of attributes in DFT power monitors of FDTD).

[Khashayar Ghaffari]

Hi Sorry for the delay. The units for each results shown in the visualizer can be found in a corresponding document page.
Here, the units for emission is 1/m (according to this article). In the edge emitting laser example we scale this and plot the stimulated and spontaneous emission results in 1/cm.
The units for the FDTD results can be found here. For example, E(t) has a unit of V/m and H(t) has a unit of A/m.
Best regards

[nuaman98]

Hi I met with another error. "Found zero bound state in the conduction band quantum well for the given boundary condition".
This happens when the top and bottom layers extra thickness is reduced keeping the boundary condition as hard wall. Can you please explain on this?

[Khashayar Ghaffari]

Hi As the error suggests the issue is that no bound states are found in the conduction band. This means the eigen states havenÔÇÖt decayed enough at the wall boundary; this is most likely due to the changes in your settings related to the barrier layers and boundary conditions. It is best to extend the simulation region by a thick enough buffer layer on both sides to ensure that the wave function decays sufficiently towards the boundaries (10 nm or more depending on the barrier height) regardless of the thickness of the inner barriers. If a state is confined it should go to zero near the boundaries.
In general the boundary conditions used in the MQW solver Application Gallery examples should be suitable for most simulations. I recommend looking into the following article which describes MQW boundary conditions and best practices in more detail:
https://support.lumerical.com/hc/en-us/articles/4408301526291-Setting-the-Boundary-Conditions-of-the-MQW-Solver
On another note, please create new posts for questions with new subject.
Best regards