Semiconductors: how to calculate the electrical resistivity of a semiconductor

Hello friends of steemit, this time I want to explain a bit of how we can determine the resistivity of a semiconductor through the two-point method.

Resistivity is a characteristic of a material and has units of Ω.cm (ohms x centimeters) and indicates that both material is opposed to the passage of current.

Do not confuse electrical resistivity with electrical resistance. They are two different concepts.

Electrical conductivity (σ) is the ability to conduct electric current when a potential difference is applied, it is one of the most important physical properties in a semiconductor or a solid.

If you want to know a little more about the resistivity and electrical conductivity here the link: [1]

Experimental procedure of electrical resistivity.

To determine the electrical resistivity using the two-point method, the experiment consists of having a sample in the form of a parallelepiped, then made electrical contacts as shown in the figure.

Experimental setup under ASTM F43-99

Now check if the contacts are ohmic.

  

                         Image source: google                                         Image source: google

When I say if the contacts are ohmic I mean that when you run the current through the positive or negative end, the voltage value should be the same.

If the contacts are ohmic we proceed to circulate electrical current (I) from (1E-2 Amp to 1E-9 Amp) until the conduction mechanism is activated and the value of the voltage and current is taken to calculate the electrical resistivity, Use the following equation:

                                                             δ(Ω.cm) =  ae/d . V/I 

Where: a: is the width of the sample e: thickness of the sample and d: distance of the points.

Well that's the whole procedure for calculating the electrical resistivity of a semiconductor, it's a relatively simple procedure.