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evaluating photo diode efficiency vs. wavelength
Posted Jun 18, 2009, 7:38 p.m. EDT 1 Reply
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Hi,
just a quick note about some of my recent experiments and the related issues.
I'm trying to simulate the wavelength dependence of different photodiode structures in silicon. Right now I'm just using n-k-data for intrinsic silicon to model the penetration depth versus wavelength in 2D. To measure the absorption in a particular region of the semiconductor, I measure the difference in power flow at the top and bottom of this region - neglecting space-charge regions, doping and biasing effects etc.
Some observations (from rfweh mode):
- while integrating in a subdomain I have access to normPoav which is the relevant data, but integrating over an internal boundary there is only nPoav available in the list box - why? Typing normPoav seems to return meaningful data though, thus I hope I can trust the data
- is there a way to directly obtain differences between two boundary integrals using the GUI? So far I'm calculating and storing the individual results in a script and postprocess them.
- I'd prefer not to draw too many internal boundaries to get access to the integral in that depth, but did it for easier scripting. It is possible to do a cross-section analysis in the GUI to get the power flow in an arbitrary depth, but it is a bit tricky to do that in the script because it takes some time to figure out the commands and correct options. In some cases it's possible to "steal" the commands by saving the model to a .m-file, but it didn't work in this case. Is it possible to create a log file which contains a list of all executed commands? I think this would be of great value and save a huge amount of time
Did someone already do a full absorption model with doping and biasing effects?
best regards
Guenter Grau
just a quick note about some of my recent experiments and the related issues.
I'm trying to simulate the wavelength dependence of different photodiode structures in silicon. Right now I'm just using n-k-data for intrinsic silicon to model the penetration depth versus wavelength in 2D. To measure the absorption in a particular region of the semiconductor, I measure the difference in power flow at the top and bottom of this region - neglecting space-charge regions, doping and biasing effects etc.
Some observations (from rfweh mode):
- while integrating in a subdomain I have access to normPoav which is the relevant data, but integrating over an internal boundary there is only nPoav available in the list box - why? Typing normPoav seems to return meaningful data though, thus I hope I can trust the data
- is there a way to directly obtain differences between two boundary integrals using the GUI? So far I'm calculating and storing the individual results in a script and postprocess them.
- I'd prefer not to draw too many internal boundaries to get access to the integral in that depth, but did it for easier scripting. It is possible to do a cross-section analysis in the GUI to get the power flow in an arbitrary depth, but it is a bit tricky to do that in the script because it takes some time to figure out the commands and correct options. In some cases it's possible to "steal" the commands by saving the model to a .m-file, but it didn't work in this case. Is it possible to create a log file which contains a list of all executed commands? I think this would be of great value and save a huge amount of time
Did someone already do a full absorption model with doping and biasing effects?
best regards
Guenter Grau
1 Reply Last Post Jun 23, 2009, 10:24 a.m. EDT
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Posted:
2 decades ago
Hi Guenter,
You can use integration coupling variables to combine the values of two or more boundary integrals. The most convenient way is to define just one boundary integration coupling variable, but with different expressions on different boundaries. In your case, you would use the expression normPoav_rfweh on one of the boundaries and the negative, -normPoav_rfweh, on the other one. Once you have solved or updated your model, you can evaluate the result by typing the variable name in for instance Postprocessing > Data Display > Global.
The reason nPoav but not normPoav is listed is that only the former is defined specifically on boundaries. Both are OK to use, but note the distinction: while normPoav gives the norm of the power flow no matter the direction, nPoav gives the component perpendicular to the boundary. To make sure that these expressions give you what you need, I would recommend that you check out their definitions, under Physics > Equation System > Subdomain (or Boundary for nPoav) Settings. Click the Variables tab and scroll through the list.
Best,
Linus Andersson
You can use integration coupling variables to combine the values of two or more boundary integrals. The most convenient way is to define just one boundary integration coupling variable, but with different expressions on different boundaries. In your case, you would use the expression normPoav_rfweh on one of the boundaries and the negative, -normPoav_rfweh, on the other one. Once you have solved or updated your model, you can evaluate the result by typing the variable name in for instance Postprocessing > Data Display > Global.
The reason nPoav but not normPoav is listed is that only the former is defined specifically on boundaries. Both are OK to use, but note the distinction: while normPoav gives the norm of the power flow no matter the direction, nPoav gives the component perpendicular to the boundary. To make sure that these expressions give you what you need, I would recommend that you check out their definitions, under Physics > Equation System > Subdomain (or Boundary for nPoav) Settings. Click the Variables tab and scroll through the list.
Best,
Linus Andersson