Thanks very much dear Till.

But I have also noticed this unit in experimental work!!!!!!

Hi. as Tillmann said, this presentation for clear comparison of currents in the devices with different dimensions. Its very important to know the current/width of channel, specially in 2D electronic devices. It is should be used in both experimental and theoretical results. Specially in 2D materials, since lower dimensional devices show higher contact resistance depending on width.

Hi

Thank you both for this. it is now clear to me

It is done to normalize the current to compare device with different dimensions.

Thanks dear Vikas

I agree with  Vikas 

Thanks for all

It don due to gate length considerations. Thanks

Thanks

Current through the channel actually depends upon the distribution of potential inside the channel. The main concept behind this representation is the invariance of potential. And the story is same for MESFET/MOSFET/SOI or any other field-effect-transistor. (In case of nanowire FET, representation is same, but meaning is a little bit different.)

Along the channel, there is zero potential at the source contact (since it is grounded), some constant potential at the gate contact and positive potential at the drain. As a result, if you go from source to drain, the potential is continuously increasing at each successive point inside the channel.

But, along the width of the channel, there is no variation of potential. And no potential variation means no effect on the current at all! That is why current of a device can be expressed as per unit width (A/width, or A/mm). The device having two times width will simply give twice as much current. The representation also normalizes the current and allows the comparison among devices with different width. (A 2D simulation means you are simulating a device having one unit width. So the result here is automatically normalized.)

But in the same way, you can not normalize the current per unit gate length or per unit channel thickness, since the potential varies with length and width. So, double the channel thickness does not offer double drain current in general.

Thanks very much

Dear Nouredine Sengouga,

It is used for the current normalization and is also applicable to other FETs