ECE 440 Homework VI Spring 2006 Due: Monday, February 20, 2006 1. (a) An n-type Si sample with N d = 1x10 17 /cm 3 is steadily illuminated such that g op = 3x10 21 EHP/cm 3-s. If τ n = τ p =1 μs for the excitation, calculate the separation in the quasi-Fermi levels, (F n-F p ). Draw a band diagram such as Fig. 4-11. (b) At t=0, the illumination in part (a) is terminated. Assuming the carrier lifetimes remain the same, calculate the separation in the quasi-Fermi levels at t=4 μs. Draw a corresponding band diagram at 300 K. 2. Refer to problem 1 part (a) in HW V. The same silicon bar is steadily illuminated at 300 K and a uniform excess carriers are generated in the Si bar. Assume that
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