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Unformatted text preview: o o o material is found to be 1.08 m and that of holes 1.5 m , w here m is the free electron rest D mass. A sample of this material is doped n-type w ith N = 10 cm and is found to have a 16-3 resistivity of 0.2 S-cm. (a) What is the electron mobility at room temperature for this sample? (b) Calculate the mean time betw een collisions for the electrons in the conduction band. c (c) The average energy of these electrons in the conduction band is [E + (3/2)kT], c w here E is the conduction band edge. If all of the (3/2)kT is kinetic energy, w hat is the average thermal speed of these electrons? (d) What is the average distance traversed by the electrons betw een collisions (mean free path)? (f) There is a strong impetus to make solid state devices ever smaller in size. Using this semiconductor, can devices be made up to the point w here the concept of mobility is no longer valid....
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