Semiconductor quantum dots


#1

Hi I am trying to simulate semiconductor quantum dots for luminescent solar concentration application. In some papers I have seen people defining emission quantum efficiency of quantum dots. It would be great if someone can tell me how to set the material property so that my structure acts as quantum dots. I have the n,k values of the material. And also how to set emission quantum efficiency of such quantum dots?

Thanks in advance


solar luminescent concentrators
#2

Dear Farsad,

To calculate the quantum efficiency of an emitter, it is possible to represent the quantum dot emitter by using a dipole source instead of by simulating the physical structure of the emitter.

The following example shows the calculation of quantum efficiency for an emitter placed near the surface of a gold nanoparticle where the decay rate of the emitter is modified by the presence of the gold nanoparticle:
https://kb.lumerical.com/en/index.html?sp_fluorescence_enhancement.html

Please take a look and let me know it looks like the type of calculation that you are interested in.


Quantum Dot Solar Cell
#3

This was very helpful, thank you. I’m still having trouble figuring out what effect the dipole material has on the simulation. In the example in your link, the dipole source is a small Au nanoparticle, but how could we input our own material for this purpose? I would like to use a ZnS quantum dot, that is excited at 300 nm.


#4

In the fluorescence enhancement example, the power emitted by the dipole source is used to calculate the quantum efficiency, and the actual material of the emitter is not considered.

In the following example, a quantum dot is represented by a gain material which is excited by an input beam:
https://kb.lumerical.com/en/index.html?gain_quantum_dot_laser.html

However, I think the main consideration was just the gain of the material since the quantum dot itself is taken to be very small.

It may be worth doing a literature search to see if there are any publications where the FDTD method has been used to simulate quantum dots of a given material in order to see what considerations need to be made in order to include the effect of the material. I would be interested to look into any additional information you may find!


#5

Hi, I’m wondering if there has been any development in this question.

I was thinking about the validity of using a point dipole to represent a quantum dot instead of inputting the materialwith its optical properties. So far I could only find papers that use dipoles to represent QDs, with comments that the point dipole approximation fails at extremely small distances (order of a few Angstroms).