Hai!! Good day

I am using the MOSFET as transducer to attract the electrochemical potential in buffer pH solution. my concern is choose the size of transistor based on the operation current (I bias). The MOSFET is biased at constant current (Id) and constant voltage (Vds) by fixing the Vgs. By increase the width of MOSFET(L= constant), the current Id will increase. Therefore, the transconductance, gm will increase.

I am using a simple circuit to investigate the input noise at the Gate terminal and the output noise at drain terminal of MOSFET

Based on my understanding
The formula of the noise voltage source which series the gate terminal ;
Svg(f) = Kf/2u(Cox^2)WLf

Sid(f) = kf(Ids)/Cox(L^2)f

Increase the Width (W), the noise voltage source at gate terminal will be reduced. Unfortunately, the current noise (Sid) will increase as increase the drain current Id (width increase).


My question are;

(i) is it the way of my investigation is correct? I mean the schematic that I draw (attechement)? and, is there any better configuration or the best approach to investigate noise of single MOSFET at simulation level?

(ii) Using the MOSFET as transducer(sensor), what should I consider? increase the gm so that the Svg(f) reduce but the Sid(f) is increase or reduce the gm so that the Sid(f) reduce but Svg(f) increase?

Thanks
Adi