ECE209 Sample Quiz 2 - 1 Use below information for the following problems if required: me = 9.11×10-31 kg, h = 6.626×10-34 Js, k = 1.38 × 10-23 J/K , kT (at T=300K) = 0.0259 eV For silicon: ni =1.0×1010cm-3 , NC = 2.81×1019 cm-3 , NV = 1.83×1019 cm-3 , Eg = 1.11 eV 1. Explain qualitatively what happens to electron concentration of a doped Silicon sample at different temperatures (50K to 500K) 2. Determine the equilibrium electron and hole concentrations inside a uniformly doped sample of Si under the following conditions. For each of the conditions draw a carefully dimensioned energy band diagram for the Si sample. (a) T = 300 K, ND = 1015 cm-3. (b) T = 300 K, NA = 1015 cm-3. (c) T = 300 K, NA = 9×1015 cm-3, and ND = 1016 cm-3. 3. Determine the conductivity of a sample of Si at 400K which is uniformly doped with 5×1017 cm-3 phosphorus. (Consider the effect of temperature and impurity on mobility using the graph below) 1 ECE209 Sample Quiz 2 - 1 4. In InSb at 300 K, EG = 0.18 eV, me*/me = 0.0116, mh*/me = 0.40, and ni = 1.6×1016 cm-3. Draw a dimensioned energy band diagram showing the positioning of EFi . 5. A sample of Si is doped with 1017 phosphorus atoms/cm3. What would you expect to measure for its resistivity? What Hall voltage would you expect in a sample of 100 μm thick if Ix=1mA and Bz=1kG=10-5 Wb/cm2? 2 ECE209 Sample Quiz 2 - 1 3

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