a$.$ When we make a contact between n$-$doped semiconductor and metal, it will be better to use the metal with high workfunction.$$

b$.$ In MOS capacitor, the surface potential will proportionally increase as the applied gate voltage increases.

c$.$ AC capacitance show how much charge can follow the change of the applied signal.

d$.$ On current of MOSFETs does not always follow $$square law$$ because of $$velocity saturation$$

e$.$ In Schottky diode devices, carrier transports only in one direction.