I am doing a study on p-type AlGaN and attempted to do current-voltage (IV) as well as Hall effect to measure the electrical properties of a sample. My fellow colleagues made mention of the destructive effect of IV and Hall effect and that I would not be able to do other measurements after that (such as photoluminescence or XRD). Can somebody explain on what effects electrical characterization has on an entire thin film sample such as AlGaN?
Well, if you stick to low voltages, you're safe, but if you go to higher voltages, the current might find new ways - and that goes along with rearrangements/reorganisations/reconstructions... of the structure.
But anyway, why not just perform XRD and PL first so you know you're done with it?
Noor Afifa Mohd Hanafiah With lower voltages and current, Hall measurement will not damage your sample. For IV measurement, the device structure will determine whether the measurement will damage the epilayers. For relatively large structures with a contact spacing of 10-15 microns applying 10-15 V should be fine assuming the doping density is not too high.
Jürgen Weippert and Towhidur Razzak Thank you for your replies! Will take your suggestions and notes into account.
This is good question.
At first i would tell you that already devices called Hall generators used to sense the electric field or measure the power or contactless current measurement of currents.
These devices must preserve their properties otherwise they could not be used in such applications.
From the principle point of view one has to care of the specimens during the measurements not to make any irreversable changes in the material or the electrodes of the measurements. As the colleagues said you have to limit your current in the specimen otherwise you can heat it up and even you can burn it at excessive current.
There is a concept in the measurement you have to make measurements under the lowest possible excitation not to affect any changes in the material properties. For example even warming it may affect it properties without damaging it and when you remove the excitation it will return to its initial conditions even after long time. If you affect any irreversible changes by your strong excitation, the specimen will not return to original state.
Best wishes
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