Naked Science Forum
Non Life Sciences => Technology => Topic started by: RizJay on 31/07/2022 15:20:09
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I am conducting a project where I am running a set of characterization tests on a group of 10 different silicon photodiode detector models.
The 10 detector models to be tested vary in many ways including: which wavelength they are optimally sensitive to; what the maximum voltage applied to each should be; the current level which flows in the device absent of light (dark current); C-V and I-V relationships.
The characterization tests are: Capacitance-Voltage testing; Current-Voltage testing; Dark Current stability testing; Spectral Responsivity testing & UV stability testing.
I understand the basics of how silicon photodiodes operate - the P-N junction, and reverse/zero bias mode, how capacitance and dark current relate to bias setup etc - and I understand each of the terms/qualities which are being tested. I also know how to conduct each test and how to plot the results and compare them.
What I need is someone to please explain to me is WHAT CAN BE LEARNED from these characterisation tests? I have been learning about these devices and their operation, and what is being measured by each test. I am familiar with each of them but I just need someone to PLEASE spell out what information can be learned from performing these tests.
Is it simply that I will learn which application each device is best suited to? Is it how future devices could be designed?
Thanks in advance.
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what information can be learned from performing these tests.
It sounds like you have already learned a great deal from the testing you are doing.
- And as you try to turn the individual test results into a coherent overview, I am sure you will learn even more!
- If it is a university exercise, then the purpose will be learning about photodetectors, and learning about laboratory work, learning about experimental error, and learning how to write reports
- If it is an exercise in industry, then someone will have some ulterior motive, like imagining some application. If you knew the application, it may allow you to make more focused conclusions.
- It is quite possible that the intent is to select a set of photodetectors that cover the widest available range of wavelengths. In that case, what you are doing is developing the calibration curve that will be installed as the factory default in the software. Presumably, this initial default will be refined by some factory or field calibration method?
If you have more time, you might also learn more by seeing how:
- The performance varies with temperature (dark current increases significantly with temperature)
- Select devices from different manufacturing batches, to see how device performance will vary between individual devices.
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I think you are looking down the wrong end of the microscope! Electro-optical devices have been around long enough that, unlike the original germanium phototransistors, every product on the market has been designed for a specific application in terms of its spectral response, junction area, junction capacitance, etc.