Since the HW assignment due on Tuesday may be fairly short and perhaps insufficiently challenging, you are invited to work on the following extended problem.
Consider a semiconductor model characterized by: Eg=1.eV, Nv=Nc=5x10^18 cm-3. For x less than 0 it is doped with 10^16 acceptors/cm-3. For x greater than zero, it is doped with 10^16 donors/cm^3. (pause and draw a picture here)
Let us assume --and this is a big leap-- that all the excess electrons in the "slice" between x=0 and x=d (d is some distance, as yet undetermined), sneak over to the x less than zero side and reside in the region between x=-d and x=0.
Graph the (net) charge as a function of x. Graph the electric field associated with that charge as a function of x.
Feel free to ask questions or discuss here via comments. All comments should be in your own words; do not site outside authorities.
You are encouraged to work on this, but it is optional. Work you hand in on this should be well-presented with appropriate size graphs (i.e., small, e.g., 3"x3" more or less) embedded along with text.
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Some review of E&M may be needed here. It will be well worth your while to undertake that. In addition to the relation between charge and electric field, you may wish to think about the relation between electric field and potential,and apply that to this problem, going beyond what is asked above.
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