Answer Happy

Question 6: Using the fact that the applied field, Es=, where L is the length of the sample determine an equation for the electron mobility in terms of four measureable quantities (d, t, L, Vs). Note the differences between d and L. [3] Based on your text book 'Semiconductor Physics and Devices', by Donald A. Neamen, the diffusion coefficient of the electrons can be calculated by use of studying the detected pulse, as sketched in Figure 2, and the below derived equation, Dn= (μE)² (At)² 16t (4a) where, At = t₂-t₁. (4b) Vc La t Figure 2 - Collected excess carrier pulse versus time arriving at contact C We will not calculate the diffusion constant in this assignment. [If you wish to do this calculation for marks then you need to fail this course this year as it will be assessed next year.] The area, A under the curve (Figure 2) is proportional to the number of excess electrons that have not recombined with majority carrier holes; and it is also a function t, with a general form, A(t) = Age o (5) where To is the recombination life of minority electrons. By plotting In (A/A) vs. t the recombination rate, To, can be determined. Question 7