Dr. Feimster suggests we need to ask ‘different questions’ to get a fuller understanding of what violence looked like during the Civil War:

Stamped From the Beginning suggests that even some famous Black leaders who fought for freedom exhibited ‘racist ideas about Black people’:

Dr. Feimster’s phrase, ‘we are in the archives’:

Juneteenth:

Dr. Feimster:

The author of Stamped From the Beginning argues that historically, racist ideas led to the creation of racist policies:

Question 3 (40 points) Consider an n-type silicon wafer with a donor concentration of Nd = 2×1014 atoms/cm3. (a) Determine the temperature at which the intrinsic carrier concentrations is equal to the extrinsic electron concentration. To simplify your calculation, please assume complete ionization of the donors, and also NC, NV, and Eg are all temperature independent. Their values are given below. (12 points) (b) Determine the Fermi energy EF in EC – EF at 300 K for the n-type silicon assuming complete ionization of the donors. (10 points) (c) Calculate the electron and hole concentrations at 300 K and at 650 K. You need the result from part (a) to determine which equations to use for each temperature. (18 points) Take the bandgap of silicon as 1.12 eV, NC = 2.80×1019 cm–3, NV = 1.04×1019 cm–3, Boltzmann constant 1.38×10–23 J/K, and 1 eV = 1.60×10–19 J.

Question 2: (25 points) The total current through a semiconductor consists of drift currents and diffusion currents of majority carriers and minority carriers. You are given a gallium arsenide sample with a length of 1 cm. The doping concentrations in the sample are Nd = 0 and Na = 5×1015 cm–3. Assume complete ionization, mn = 8,500 cm2/V-s, mp = 400 cm2/V-s, and ni = 1.8×106 cm–3. If you apply a voltage of 1 V across the sample, what is the drift current density? e = 1.60×10–19 C (7 points) Now you create a constant excess electron concentration of 2×1015 cm–3 at the surface (x = 0) of the sample by shooting an electron beam at the surface (see the figure below): What is the spatial distribution of the excess electron concentration? Assume tn0 = 1×10–6 s (6 points) What is the electron diffusion current density for 0 < x < 1 cm? (6 points) What is the total current in the gallium arsenide sample? (6 points)

Which of the following is a runtime error in C++?

What is the output of the following Boolean expression in Python? print(True or False and False)