Midterm Exam 1 ECE103 4/24/2008 ALLOWED: Calculators and one 8.5”x11 page of notes (one side). Note you are required to turn in your page of notes with our exam. NOT ALLOWED: Textbooks, class notes, problem sets, etc. ATTEMPT ALL PROBLEMS AND SHOW ALL WORK! This exam has a maximum score of 100 points. You have 80 minutes to complete this exam. q = 1.60x10-19 C; k = 8.617x10-5 eV/K; m 0 = 9.11x10-31 kg; ε 0 = 8.85x10-14 F/cm; 1 μ m = 1x10-4 cm = 1x10-6 m; n i (Si, T=300K) = 1.0x10 10 cm-3 ; E g (Si at T=300K) = 1.12 eV. 1. BE CONCISE and do not write an essay! The ideal answer for each ma be stated in a few sentences. (a) [7 points] Explain why the large energy band gap in insulating materials leads to low electrical conductivity (compared to that in a semiconductor). (b) [7 points] Without referring to mathematical equations in your answer, explain why (in terms of physics) the intrinsic concentration increases with temperature. (c) [7 points] Explain why the law of mass action is valid only for nondegenerate semiconductors.
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This note was uploaded on 04/02/2011 for the course ECE 103 taught by Professor Song during the Spring '11 term at UCSB.