Phys 312 - Assignment 7 - Due 5 Mar 98

PLEDGED

1.

(a) Manually convert the last three digits of your Social Security number to binary form, showing all steps of the conversion

(b) Take your Social Security number, square it, and convert the result to binary form. You can do this by hand with a lot of patience, but you are expected to use a computer program (say which) or a calculator.

2.

The photoelectric effect (surface photoemission), photoconductivity, and the photovoltaic effect are similar, but different.

(a) Describe each effect and explain the differences. You can quote from books as long as you make it clear that you understand the quotations.

(b) Give an example of a practical application of each of these effects.

3.

In a p-n junction, what causes the built-in bias V_bi? In eq. (1.18'') of Melissinos, what are precisely $k,\,T,\,q,\,N_{D},\,N_{A},\,n_{i}$?
Some of these quantities are fundamental constants. What are the values of the others for a typical commercial junction? Check that they are consistent with the value V_bi=0.65 eV quoted by Melissinos.

4.

Using CMOS technology (with enhancement MOSFETS), as in Bloomfield, page 481, draw the circuit for an OR gate. Make four replicas of your drawing and indicate explicitly the voltage (or charge) on all the gates and nodes (you may just color the ones that are positive) for the four different possible inputs. Verify that the output is in agreement with the truth table for OR.