For Si and GaAs, the intrinsic electron density ni at room temperature ( K) is cm-3 and cm-3 , respectively. 

(a) The bandgap of Si is 1.1 eV at room temperature. What is the intrinsic density of electrons at 350 and 250 K. In a semi-logarithmic plot, draw the intrinsic density of electrons as a function of . 

(b) Given the effective mass and for Si, what is NC and N V (cm-3 ) at room temperature ( kg). 

(c) What is the position of intrinsic Fermi energy for Si with respect to the middle of the band gap at room temperature? 

(d) Given that for GaAs the intrinsic carrier density cm-3 at K, find the bandgap of GaAs