- A A Long Silicon Bar Is Doped With 10 5 Cm Acceptor Atoms And Is Positioned On The X Axis Electrons Are Injected Suc 1 (72.85 KiB) Viewed 17 times
(a) A long silicon bar is doped with 10¹5 cm³ acceptor atoms and is positioned on the x-axis. Electrons are injected such that the steady-state excess electron concentration is 3 × 10¹4 cm²³ at x = 0. Assuming that n = 1500 cm²V-¹s¹ and Tn = 10-11 s at 300 K, find the separation between Fn and Eç at x = 500 Å. (b) A sample of Ge is doped with 3.5×10¹6 cm3 donor atoms and 7.8×10¹5 cm-³ acceptor atoms at 300 K. The band gap of Ge is 0.67 eV and its intrinsic density at 300 K is 2.5 x 10¹3 cm-³. (i) (ii) Calculate the position of the Fermi level (in eV) of the semiconductor sample and draw the energy band diagram. Explain why the intrinsic carrier concentration of Ge is higher than Si at T = 300 K.