Hi all,
I have been working with thin-film semiconductor devices and was subjected to severe hysteresis (occasionally) in the I-V electrical profiles that span across both positive and negative current values.
Is there any way to understand the changes ongoing from the materials perspective or is it purely a measurement artifact that I am facing?
Thanks in advance.
Dear Poh Eng Tuan
I hope that the following book is may help you.
Regards
Dear Poh Eng Tuan,
The hysteresis of IV curves on a seconductor electronic devices is directly associated with the charge carrier mobility and balance of electrons and holes.
This hysteresis (in the I-V electrical profiles) depends on:
1) the rate(s), you scan the I-V ?
and/or, depends on
2) the substrate material(s) you support your device ?
Hope you are well all!
Dear Poh
It is noticed that your current is very small. It seems me that the hysteresis observed is due to that your film behaves not only a pure resistance but also it has also capacitive effect. Since your resitance is very large , the presence of a capacitive component produces a displacement current in addition the ohmic current.
What do you make to verify this model is to slow down the scanning rate as hinted by the respected colleague professor Ioannis.
Best wishes
Dear Poh,
Lately, I stumbled upon your question. I think the answer can be more elaborated from the material perspective.
Generally, when we talk about quasi-static IV measurements, we should have sufficiently long dwell time at each voltage data point. It allows the device's thermal and transient trapping processes to reach a steady state. If you don't wait for enough time which depends on voltage sweep rate, then you will see a dependence due to these processes in your data manifested as hysteresis.
These processes have a different time constant (~RC) depending on the device and can be related to their respective resistance and capacitance as said by other here. If the process is slow, you will have to wait for longer at each voltage leading to slow scan rates. You can make a pulse measurement to get an estimate of the response time of your device and then appropriately change your sweep rate. Sometimes, these processes are quite long like in organic semiconducting devices, and you will see them always. Whether you should wait longer or not depends on what is the typical device operation. If you meant to use it at a fixed voltage then for accurate IV measurement, you should wait longer. If you want to use it at high frequency, then instead of DC IV measurement, go for pulsed IV measurements where thermal and trapping processes don't have the time to occur. The pulsed measurement if not done correctly, can lead to measurement artefacts, see ref 2. I hope it helps.
[1].https://www.researchgate.net/publication/242257169_The_importance_of_sweep_rate_in_DC_IV_measurements
[2].https://www.keysight.com/upload/cmc_upload/All/9Feb14Slides.pdf
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