8/14/2019 HW1_solutions EE3310.pdf

1/2

EE3310 Homework #1

Summer 2011 Solutions

1. Use Appendix III (attached) of Streetman and Banerjee to answer the followingquestions:a. Which semiconductor has the lowest density? Siliconb. Which semiconductor has the smallest bandgap energy (Eg)? InSbc. What wavelength corresponds to the bandgap energy of InP? In which part of

the spectrum is this wavelength? (Infrared, Visible, Ultraviolet, etc.)919 nm [near infrared] (use = hc/Eg)

d. Name four of the II-VI semiconductors listed in Appendix III along with theirlattice constants (a). Any of the Zn, Cd, or Pb compounds

2. Find the fraction of the bcc (body centered cubic) unit cell volume that canpossibly be filled by hard spheres.

(8/3) (sqrt(3)/4)3= 0.68 or 68%

3. Label the planes illustrated below. (Miller Notation.)Note: plane (a) is parallel to the z-axis, and plane (b) is parallel to the x-axis.For a reference tutorial, see

http://www.doitpoms.ac.uk/tlplib/miller_indices/intro.php

(a) (530) (b) (011)

4. Answer the following questions: Answers givena. Find the number of atoms/cm2on the (100) surface of a Si wafer. (Ans:

6.8e14)

b. Find the distance (in nm) between nearest neighbor Ga atoms in GaAs.(Ans: 0.399 nm)

5. How many atoms are found inside the unit cell of:a. A simple cubic lattice. 1 and a(for part d)b. A body centered cubic lattice. 2 and sqrt(3)*a/2 )c. A face centered cubic lattice. 4 and a/sqrt(2)d. How far apart are the nearest neighbor atoms in each case measured center

to center of the atoms. (Put your answer in terms of the lattice constant a.)

6. Can a particle within an infinite potential well have zero energy? Why?

8/14/2019 HW1_solutions EE3310.pdf

2/2